Open Source Ecology - User contributions [en]

StableConcrete

2021-07-26T00:13:47Z

ChuckH: Last several edits were fixing broken links

= Stable Concrete for Machine Frames =

In a general sense, "concrete" refers to a combination of aggregate (stone, gravel, sand, etc) and a binder (portland cement, epoxy, etc) which hardens into a solid mass. Everyday construction concrete, PCC (Portland Cement Concrete), is based on [[Wikipedia:portland cement|portland cement]]. "Polymer concrete" uses polymer resin (e.g. epoxy), instead of cement, to hold the aggregate together.

Concrete is an attractive material for machine tool frames because
* it is moderately stiff (though much less stiff than cast metals)
* it absorbs vibration well
* it is very easy to cast into arbitrary shapes
* it is low cost

Machine tool frames made of PCC date at least as far back as the [https://www.engineeringforchange.org/news/2011/07/31/the_concrete_lathe_world_war_i_technology_meets_21st_century_design.html Yeoman lathe], (see also [http://www.google.com/patents/US3800636 Zagar]) but have never been widely adopted.
In contrast, since the 1980s, polymer concrete has become quite popular in construction of precision machine tools, first in Europe and now worldwide [https://www.americanmachinist.com/archive/features/article/21892630/rocksolid-machine-bases]. The first commercially important concrete for this purpose was the epoxy-granite composite [http://www.adgrind.com/Studer/Granitan/granitan.htm Granitan], made by the Swiss grinding-machine manufacturer Studer.

Polymer concretes have much better dimensional stability than PCC. [http://books.google.com/books?id=uG7aqgal65YC&pg=PA317#v=onepage&q&f=false Slocum] declares PCC unsatisfactory for precision machinery due to:
* reaction shrinkage from cement hydration
* shrinkage due to loss of excess nonstoichiometric water, which leaves conduits for humidity-induced expansion or contraction, and
* non-elastic dimensional changes (e.g. creep and microcracking in the inherent brittle/porous structure).
A [http://dx.doi.org/10.1016/0141-6359(85)90041-8 scientific paper] comparing PCC and polymer concretes in machine tool applications was published by a Studer researcher in 1985. Another article [http://dx.doi.org/10.1016/S0007-8506(07)61657-6 here].

While polymer concrete provides one route to resolving these PCC problems, it is much more costly than PCC and is less compatible with the OSE requirements. It is worth revisiting the application of "plain old concrete" to machine frames with an eye to ameliorate its known weaknesses. Some results cited [[#HolographyTable|below]] suggest that with adequate curing time, surface painting to suppress humidity exchange, and post-tensioned reinforcement, PCC can provide excellent stability.

== PCC shrinkage behavior ==

PCC shrinkage during cure is 0.04 - 0.1%, and shrinkage continues at slower and slower rate for months or years. It is necessary to be patient -- probably waiting 1 to 3 months before considering the concrete dimensionally stable. TBD: do thinner sections stabilize more quickly, and if so, how much?

After the curing process is essentially finished, the concrete remains humidity-sensitive, a bit like wood -- expanding in high humidity and contracting when air is dryer. Concrete also responds to temperature: it has a thermal expansion coefficient close to that of steel. Sealing the surface with paint or similar coating can greatly reduce humidity effects. (This should also reduce carbon dioxide absorption, which causes an additional shrinkage chemical reaction: carbonation.)

In "latex concrete", which is PCC with a substantial addition of acrylic or SBR polymer emulsion, most of the pores are filled with polymer; this tends to reduce shrinkage, make the concrete more stable against moisture-related effects, and make it less brittle. Using acrylic latex concrete for thin-shell roofs is described [http://ceae.colorado.edu/mc-edc/pdf/Acrylic%20Concrete%20Roofs.pdf here]. [https://wiki.opensourceecology.org/images/e/ef/Mastercast-141-tds.pdf Rheomix 141], a styrene-butadiene copolymer, has also been recommended for that application. It seems likely that one of these admixtures would considerably improve the stability of a cast-concrete machine base.

== Steel reinforcement ==

PCC is strong in compression but much weaker in tension. The loads on a machine frame will typically put some parts of the frame in tension, and these parts must be reinforced. The simplest support is to cast reinforcing bar (rebar) into the concrete mass. While rebar makes the section strong, it also, ironically, is almost certain to make it filled with small cracks. This is because the concrete sets and locks to the rebar long before it finishes shrinking[https://wiki.opensourceecology.org/images/8/8c/ACI_224R-01_Control_of_Cracking_in_Concrete_Structures_f224R%2801%29Chap3.pdf]:<br>[[File:Cracking.png |border]]<br>'''Figure: Crack development during curing of concrete with embedded steel reinforcement bar'''

To avoid this, the concrete should use ''post-tensioned'' steel reinforcement. By maintaining the concrete always in compression, and never above 30% of the ultimate compressive stress limit, the concrete microstructure will remain quite stable[http://www.cv.titech.ac.jp/~courses/atce1/dim_stab.pdf],[https://wiki.opensourceecology.org/wiki/File:Dim.pdf].

== Recommendations ==

To obtain a dimensionally stable frame, the following steps are recommended:
* Use aggregate crushed from a dense, stable mineral, preferably granite, limestone, or quartz.
* Post-tension the assembly after ~4 weeks cure
* Paint all surfaces after ~90 days cure
** Might be possible to paint sooner; TBD
** The paint should provide a vapor barrier. In concrete-sealing parlance this requires a "pore-blocker" or barrier treatment, such as epoxy or HMWM (High molecular weight methacrylate), ''not'' a breathable water repellant such as silane or siloxane.
** There is a huge variety of concrete sealing products being sold but little hard information on what works best as a vapor barrier (and whether it works any better than asphaltic mastic or a standard wall paint).

<div id="HolographyTable"></div>These folks wanted stability (world's largest laser holography table in 1993[http://smartec.ch/HTMLFiles/Concrete_holography_table_IMM.htm],[https://spie.org/Publications/Proceedings/Paper/10.1117/12.155030]) and got this:<br>[[File:Shrinkage.png |border]]<br>
The stability reached after 120 days (~ +/-0.2mm over 20m, ~1e-5) is very promising for a machine tool application. The authors ascribe the residual dimensional changes to seasonal temperature variation.

==GVCS applications==

*{{Lathe}}
* {{Steam Engine}}

StableConcrete

2021-07-25T22:21:57Z

ChuckH: /* Steel reinforcement */

= Stable Concrete for Machine Frames =

In a general sense, "concrete" refers to a combination of aggregate (stone, gravel, sand, etc) and a binder (portland cement, epoxy, etc) which hardens into a solid mass. Everyday construction concrete, PCC (Portland Cement Concrete), is based on [[Wikipedia:portland cement|portland cement]]. "Polymer concrete" uses polymer resin (e.g. epoxy), instead of cement, to hold the aggregate together.

Concrete is an attractive material for machine tool frames because
* it is moderately stiff (though much less stiff than cast metals)
* it absorbs vibration well
* it is very east to cast into arbitrary shapes
* it is low cost

Machine tool frames made of PCC date at least as far back as the [https://www.engineeringforchange.org/news/2011/07/31/the_concrete_lathe_world_war_i_technology_meets_21st_century_design.html Yeoman lathe], (see also [http://www.google.com/patents/US3800636 Zagar]) but have never been widely adopted.
In contrast, since the 1980s, polymer concrete has become quite popular in construction of precision machine tools, first in Europe and now worldwide [https://www.americanmachinist.com/archive/features/article/21892630/rocksolid-machine-bases]. The first commercially important concrete for this purpose was the epoxy-granite composite [http://www.adgrind.com/Studer/Granitan/granitan.htm Granitan], made by the Swiss grinding-machine manufacturer Studer.

Polymer concretes have much better dimensional stability than PCC. [http://books.google.com/books?id=uG7aqgal65YC&pg=PA317#v=onepage&q&f=false Slocum] declares PCC unsatisfactory for precision machinery due to:
* reaction shrinkage from cement hydration
* shrinkage due loss of excess nonstoichiometric water, which leaves conduits for humidity-induced expansion or contraction, and
* non-elastic dimensional changes (e.g. creep and microcracking in the inherent brittle/porous structure).
A [http://dx.doi.org/10.1016/0141-6359(85)90041-8 scientific paper] comparing PCC and polymer concretes in machine tool applications was published by a Studer researcher in 1985. Another article [http://dx.doi.org/10.1016/S0007-8506(07)61657-6 here].

While polymer concrete provides one route to resolving these PCC problems, it is much more costly than PCC and is less compatible with the OSE requirements. It is worth revisiting the application of "plain old concrete" to machine frames with an eye to ameliorate its known weaknesses. Some results cited [[#HolographyTable|below]] suggest that with adequate curing time, surface painting to suppress humidity exchange, and post-tensioned reinforcement, PCC can provide excellent stability.

== PCC shrinkage behavior ==

PCC shrinkage during cure is 0.04 - 0.1%, and shrinkage continues at slower and slower rate for months or years. It is necessary to be patient -- probably waiting 1 to 3 months before considering the concrete dimensionally stable. TBD: do thinner sections stabilize more quickly, and if so, how much?

After the curing process is essentially finished, the concrete remains humidity-sensitive, a bit like wood -- expanding in high humidity and contracting when air is dryer. Concrete also responds to temperature: it has a thermal expansion coefficient close to that of steel. Sealing the surface with paint or similar coating can greatly reduce humidity effects. (This should also reduce carbon dioxide absorption, which causes an additional shrinkage chemical reaction: carbonation.)

In "latex concrete", which is PCC with a substantial addition of acrylic or SBR polymer emulsion, most of the pores are filled with polymer; this tends to reduce shrinkage, make the concrete more stable against moisture-related effects, and make it less brittle. Using acrylic latex concrete for thin-shell roofs is described [http://ceae.colorado.edu/mc-edc/pdf/Acrylic%20Concrete%20Roofs.pdf here]. [https://wiki.opensourceecology.org/images/e/ef/Mastercast-141-tds.pdf Rheomix 141], a styrene-butadiene copolymer, has also been recommended for that application. It seems likely that one of these admixtures would considerably improve the stability of a cast-concrete machine base.

== Steel reinforcement ==

PCC is strong in compression but much weaker in tension. The loads on a machine frame will typically put some parts of the frame in tension, and these parts must be reinforced. The simplest support is to cast reinforcing bar (rebar) into the concrete mass. While rebar makes the section strong, it also, ironically, is almost certain to make it filled with small cracks. This is because the concrete sets and locks to the rebar long before it finishes shrinking[https://wiki.opensourceecology.org/images/8/8c/ACI_224R-01_Control_of_Cracking_in_Concrete_Structures_f224R%2801%29Chap3.pdf]:<br>[[File:Cracking.png |border]]<br>'''Figure: Crack development during curing of concrete with embedded steel reinforcement bar'''

To avoid this, the concrete should use ''post-tensioned'' steel reinforcement. By maintaining the concrete always in compression, and never above 30% of the ultimate compressive stress limit, the concrete microstructure will remain quite stable[http://www.cv.titech.ac.jp/~courses/atce1/dim_stab.pdf],[https://wiki.opensourceecology.org/wiki/File:Dim.pdf].

== Recommendations ==

To obtain a dimensionally stable frame, the following steps are recommended:
* Use aggregrate crushed from a dense, stable mineral, preferably granite, limestone, or quartz.
* Post-tension the assembly after ~4 weeks cure
* Paint all surfaces after ~90 days cure
** Might be possible to paint sooner; TBD
** The paint should provide a vapor barrier. In concrete-sealing parlance this requires a "pore-blocker" or barrier treatment, such as epoxy or HMWM (High molecular weight methacrylate), ''not'' a breathable water repellant such as silane or siloxane.
** There is a huge variety of concrete sealing products being sold but little hard information on what works best as a vapor barrier (and whether it works any better than asphaltic mastic or a standard wall paint).

<div id="HolographyTable"></div>These folks wanted stability (world's largest laser holography table[http://smartec.ch/HTMLFiles/Concrete_holography_table_IMM.htm],[https://spie.org/Publications/Proceedings/Paper/10.1117/12.155030]) and got this:<br>[[File:Shrinkage.png |border]]<br>
The stability reached after 120 days (~ +/-0.2mm over 20m, ~1e-5) is very promising for a machine tool application. The authors ascribe the residual dimensional changes to seasonal temperature variation.

==GVCS applications==

*{{Lathe}}
* {{Steam Engine}}

File:Dim.pdf

2021-07-25T22:19:50Z

ChuckH: dimensional stability of concrete slides

dimensional stability of concrete slides

StableConcrete

2021-07-25T22:16:01Z

ChuckH: /* Stable Concrete for Machine Frames */

= Stable Concrete for Machine Frames =

In a general sense, "concrete" refers to a combination of aggregate (stone, gravel, sand, etc) and a binder (portland cement, epoxy, etc) which hardens into a solid mass. Everyday construction concrete, PCC (Portland Cement Concrete), is based on [[Wikipedia:portland cement|portland cement]]. "Polymer concrete" uses polymer resin (e.g. epoxy), instead of cement, to hold the aggregate together.

Concrete is an attractive material for machine tool frames because
* it is moderately stiff (though much less stiff than cast metals)
* it absorbs vibration well
* it is very east to cast into arbitrary shapes
* it is low cost

Machine tool frames made of PCC date at least as far back as the [https://www.engineeringforchange.org/news/2011/07/31/the_concrete_lathe_world_war_i_technology_meets_21st_century_design.html Yeoman lathe], (see also [http://www.google.com/patents/US3800636 Zagar]) but have never been widely adopted.
In contrast, since the 1980s, polymer concrete has become quite popular in construction of precision machine tools, first in Europe and now worldwide [https://www.americanmachinist.com/archive/features/article/21892630/rocksolid-machine-bases]. The first commercially important concrete for this purpose was the epoxy-granite composite [http://www.adgrind.com/Studer/Granitan/granitan.htm Granitan], made by the Swiss grinding-machine manufacturer Studer.

Polymer concretes have much better dimensional stability than PCC. [http://books.google.com/books?id=uG7aqgal65YC&pg=PA317#v=onepage&q&f=false Slocum] declares PCC unsatisfactory for precision machinery due to:
* reaction shrinkage from cement hydration
* shrinkage due loss of excess nonstoichiometric water, which leaves conduits for humidity-induced expansion or contraction, and
* non-elastic dimensional changes (e.g. creep and microcracking in the inherent brittle/porous structure).
A [http://dx.doi.org/10.1016/0141-6359(85)90041-8 scientific paper] comparing PCC and polymer concretes in machine tool applications was published by a Studer researcher in 1985. Another article [http://dx.doi.org/10.1016/S0007-8506(07)61657-6 here].

While polymer concrete provides one route to resolving these PCC problems, it is much more costly than PCC and is less compatible with the OSE requirements. It is worth revisiting the application of "plain old concrete" to machine frames with an eye to ameliorate its known weaknesses. Some results cited [[#HolographyTable|below]] suggest that with adequate curing time, surface painting to suppress humidity exchange, and post-tensioned reinforcement, PCC can provide excellent stability.

== PCC shrinkage behavior ==

PCC shrinkage during cure is 0.04 - 0.1%, and shrinkage continues at slower and slower rate for months or years. It is necessary to be patient -- probably waiting 1 to 3 months before considering the concrete dimensionally stable. TBD: do thinner sections stabilize more quickly, and if so, how much?

After the curing process is essentially finished, the concrete remains humidity-sensitive, a bit like wood -- expanding in high humidity and contracting when air is dryer. Concrete also responds to temperature: it has a thermal expansion coefficient close to that of steel. Sealing the surface with paint or similar coating can greatly reduce humidity effects. (This should also reduce carbon dioxide absorption, which causes an additional shrinkage chemical reaction: carbonation.)

In "latex concrete", which is PCC with a substantial addition of acrylic or SBR polymer emulsion, most of the pores are filled with polymer; this tends to reduce shrinkage, make the concrete more stable against moisture-related effects, and make it less brittle. Using acrylic latex concrete for thin-shell roofs is described [http://ceae.colorado.edu/mc-edc/pdf/Acrylic%20Concrete%20Roofs.pdf here]. [https://wiki.opensourceecology.org/images/e/ef/Mastercast-141-tds.pdf Rheomix 141], a styrene-butadiene copolymer, has also been recommended for that application. It seems likely that one of these admixtures would considerably improve the stability of a cast-concrete machine base.

== Steel reinforcement ==

PCC is strong in compression but much weaker in tension. The loads on a machine frame will typically put some parts of the frame in tension, and these parts must be reinforced. The simplest support is to cast reinforcing bar (rebar) into the concrete mass. While rebar makes the section strong, it also, ironically, is almost certain to make it filled with small cracks. This is because the concrete sets and locks to the rebar long before it finishes shrinking[https://wiki.opensourceecology.org/images/8/8c/ACI_224R-01_Control_of_Cracking_in_Concrete_Structures_f224R%2801%29Chap3.pdf]:<br>[[File:Cracking.png |border]]<br>'''Figure: Crack development during curing of concrete with embedded steel reinforcement bar'''

To avoid this, the concrete should use ''post-tensioned'' steel reinforcement. By maintaining the concrete always in compression, and never above 30% of the ultimate compressive stress limit, the concrete microstructure will remain quite stable[http://www.cv.titech.ac.jp/~courses/atce1/dim_stab.pdf],[http://people.ce.gatech.edu/~kk92/grad/dim.pdf].

== Recommendations ==

To obtain a dimensionally stable frame, the following steps are recommended:
* Use aggregrate crushed from a dense, stable mineral, preferably granite, limestone, or quartz.
* Post-tension the assembly after ~4 weeks cure
* Paint all surfaces after ~90 days cure
** Might be possible to paint sooner; TBD
** The paint should provide a vapor barrier. In concrete-sealing parlance this requires a "pore-blocker" or barrier treatment, such as epoxy or HMWM (High molecular weight methacrylate), ''not'' a breathable water repellant such as silane or siloxane.
** There is a huge variety of concrete sealing products being sold but little hard information on what works best as a vapor barrier (and whether it works any better than asphaltic mastic or a standard wall paint).

<div id="HolographyTable"></div>These folks wanted stability (world's largest laser holography table[http://smartec.ch/HTMLFiles/Concrete_holography_table_IMM.htm],[https://spie.org/Publications/Proceedings/Paper/10.1117/12.155030]) and got this:<br>[[File:Shrinkage.png |border]]<br>
The stability reached after 120 days (~ +/-0.2mm over 20m, ~1e-5) is very promising for a machine tool application. The authors ascribe the residual dimensional changes to seasonal temperature variation.

==GVCS applications==

*{{Lathe}}
* {{Steam Engine}}

StableConcrete

2021-07-25T22:07:50Z

ChuckH: /* Recommendations */

= Stable Concrete for Machine Frames =

In a general sense, "concrete" refers to a combination of aggregate (stone, gravel, sand, etc) and a binder (portland cement, epoxy, etc) which hardens into a solid mass. Everyday construction concrete, PCC (Portland Cement Concrete), is based on [[Wikipedia:portland cement|portland cement]]. "Polymer concrete" uses polymer resin (e.g. epoxy), instead of cement, to hold the aggregate together.

Concrete is an attractive material for machine tool frames because
* it is moderately stiff (though much less stiff than cast metals)
* it absorbs vibration well
* it is very east to cast into arbitrary shapes
* it is low cost

Machine tool frames made of PCC date at least as far back as the [https://www.engineeringforchange.org/news/2011/07/31/the_concrete_lathe_world_war_i_technology_meets_21st_century_design.html Yeoman lathe], (see also [http://www.google.com/patents/US3800636 Zagar]) but have never been widely adopted.
In contrast, since the 1980s, polymer concrete has become quite popular in construction of precision machine tools, first in Europe and now worldwide [http://www.americanmachinist.com/304/Issue/Article/False/80845/Issue]. The first commercially important concrete for this purpose was the epoxy-granite composite [http://www.adgrind.com/Studer/Granitan/granitan.htm Granitan], made by the Swiss grinding-machine manufacturer Studer.

Polymer concretes have much better dimensional stability than PCC. [http://books.google.com/books?id=uG7aqgal65YC&pg=PA317#v=onepage&q&f=false Slocum] declares PCC unsatisfactory for precision machinery due to:
* reaction shrinkage from cement hydration
* shrinkage due loss of excess nonstoichiometric water, which leaves conduits for humidity-induced expansion or contraction, and
* non-elastic dimensional changes (e.g. creep and microcracking in the inherent brittle/porous structure).
A [http://dx.doi.org/10.1016/0141-6359(85)90041-8 scientific paper] comparing PCC and polymer concretes in machine tool applications was published by a Studer researcher in 1985. Another article [http://dx.doi.org/10.1016/S0007-8506(07)61657-6 here].

While polymer concrete provides one route to resolving these PCC problems, it is much more costly than PCC and is less compatible with the OSE requirements. It is worth revisiting the application of "plain old concrete" to machine frames with an eye to ameliorate its known weaknesses. Some results cited [[#HolographyTable|below]] suggest that with adequate curing time, surface painting to suppress humidity exchange, and post-tensioned reinforcement, PCC can provide excellent stability.

== PCC shrinkage behavior ==

PCC shrinkage during cure is 0.04 - 0.1%, and shrinkage continues at slower and slower rate for months or years. It is necessary to be patient -- probably waiting 1 to 3 months before considering the concrete dimensionally stable. TBD: do thinner sections stabilize more quickly, and if so, how much?

After the curing process is essentially finished, the concrete remains humidity-sensitive, a bit like wood -- expanding in high humidity and contracting when air is dryer. Concrete also responds to temperature: it has a thermal expansion coefficient close to that of steel. Sealing the surface with paint or similar coating can greatly reduce humidity effects. (This should also reduce carbon dioxide absorption, which causes an additional shrinkage chemical reaction: carbonation.)

In "latex concrete", which is PCC with a substantial addition of acrylic or SBR polymer emulsion, most of the pores are filled with polymer; this tends to reduce shrinkage, make the concrete more stable against moisture-related effects, and make it less brittle. Using acrylic latex concrete for thin-shell roofs is described [http://ceae.colorado.edu/mc-edc/pdf/Acrylic%20Concrete%20Roofs.pdf here]. [https://wiki.opensourceecology.org/images/e/ef/Mastercast-141-tds.pdf Rheomix 141], a styrene-butadiene copolymer, has also been recommended for that application. It seems likely that one of these admixtures would considerably improve the stability of a cast-concrete machine base.

== Steel reinforcement ==

PCC is strong in compression but much weaker in tension. The loads on a machine frame will typically put some parts of the frame in tension, and these parts must be reinforced. The simplest support is to cast reinforcing bar (rebar) into the concrete mass. While rebar makes the section strong, it also, ironically, is almost certain to make it filled with small cracks. This is because the concrete sets and locks to the rebar long before it finishes shrinking[https://wiki.opensourceecology.org/images/8/8c/ACI_224R-01_Control_of_Cracking_in_Concrete_Structures_f224R%2801%29Chap3.pdf]:<br>[[File:Cracking.png |border]]<br>'''Figure: Crack development during curing of concrete with embedded steel reinforcement bar'''

To avoid this, the concrete should use ''post-tensioned'' steel reinforcement. By maintaining the concrete always in compression, and never above 30% of the ultimate compressive stress limit, the concrete microstructure will remain quite stable[http://www.cv.titech.ac.jp/~courses/atce1/dim_stab.pdf],[http://people.ce.gatech.edu/~kk92/grad/dim.pdf].

== Recommendations ==

To obtain a dimensionally stable frame, the following steps are recommended:
* Use aggregrate crushed from a dense, stable mineral, preferably granite, limestone, or quartz.
* Post-tension the assembly after ~4 weeks cure
* Paint all surfaces after ~90 days cure
** Might be possible to paint sooner; TBD
** The paint should provide a vapor barrier. In concrete-sealing parlance this requires a "pore-blocker" or barrier treatment, such as epoxy or HMWM (High molecular weight methacrylate), ''not'' a breathable water repellant such as silane or siloxane.
** There is a huge variety of concrete sealing products being sold but little hard information on what works best as a vapor barrier (and whether it works any better than asphaltic mastic or a standard wall paint).

<div id="HolographyTable"></div>These folks wanted stability (world's largest laser holography table[http://smartec.ch/HTMLFiles/Concrete_holography_table_IMM.htm],[https://spie.org/Publications/Proceedings/Paper/10.1117/12.155030]) and got this:<br>[[File:Shrinkage.png |border]]<br>
The stability reached after 120 days (~ +/-0.2mm over 20m, ~1e-5) is very promising for a machine tool application. The authors ascribe the residual dimensional changes to seasonal temperature variation.

==GVCS applications==

*{{Lathe}}
* {{Steam Engine}}

StableConcrete

2021-07-25T22:03:16Z

ChuckH:

= Stable Concrete for Machine Frames =

In a general sense, "concrete" refers to a combination of aggregate (stone, gravel, sand, etc) and a binder (portland cement, epoxy, etc) which hardens into a solid mass. Everyday construction concrete, PCC (Portland Cement Concrete), is based on [[Wikipedia:portland cement|portland cement]]. "Polymer concrete" uses polymer resin (e.g. epoxy), instead of cement, to hold the aggregate together.

Concrete is an attractive material for machine tool frames because
* it is moderately stiff (though much less stiff than cast metals)
* it absorbs vibration well
* it is very east to cast into arbitrary shapes
* it is low cost

Machine tool frames made of PCC date at least as far back as the [https://www.engineeringforchange.org/news/2011/07/31/the_concrete_lathe_world_war_i_technology_meets_21st_century_design.html Yeoman lathe], (see also [http://www.google.com/patents/US3800636 Zagar]) but have never been widely adopted.
In contrast, since the 1980s, polymer concrete has become quite popular in construction of precision machine tools, first in Europe and now worldwide [http://www.americanmachinist.com/304/Issue/Article/False/80845/Issue]. The first commercially important concrete for this purpose was the epoxy-granite composite [http://www.adgrind.com/Studer/Granitan/granitan.htm Granitan], made by the Swiss grinding-machine manufacturer Studer.

Polymer concretes have much better dimensional stability than PCC. [http://books.google.com/books?id=uG7aqgal65YC&pg=PA317#v=onepage&q&f=false Slocum] declares PCC unsatisfactory for precision machinery due to:
* reaction shrinkage from cement hydration
* shrinkage due loss of excess nonstoichiometric water, which leaves conduits for humidity-induced expansion or contraction, and
* non-elastic dimensional changes (e.g. creep and microcracking in the inherent brittle/porous structure).
A [http://dx.doi.org/10.1016/0141-6359(85)90041-8 scientific paper] comparing PCC and polymer concretes in machine tool applications was published by a Studer researcher in 1985. Another article [http://dx.doi.org/10.1016/S0007-8506(07)61657-6 here].

While polymer concrete provides one route to resolving these PCC problems, it is much more costly than PCC and is less compatible with the OSE requirements. It is worth revisiting the application of "plain old concrete" to machine frames with an eye to ameliorate its known weaknesses. Some results cited [[#HolographyTable|below]] suggest that with adequate curing time, surface painting to suppress humidity exchange, and post-tensioned reinforcement, PCC can provide excellent stability.

== PCC shrinkage behavior ==

PCC shrinkage during cure is 0.04 - 0.1%, and shrinkage continues at slower and slower rate for months or years. It is necessary to be patient -- probably waiting 1 to 3 months before considering the concrete dimensionally stable. TBD: do thinner sections stabilize more quickly, and if so, how much?

After the curing process is essentially finished, the concrete remains humidity-sensitive, a bit like wood -- expanding in high humidity and contracting when air is dryer. Concrete also responds to temperature: it has a thermal expansion coefficient close to that of steel. Sealing the surface with paint or similar coating can greatly reduce humidity effects. (This should also reduce carbon dioxide absorption, which causes an additional shrinkage chemical reaction: carbonation.)

In "latex concrete", which is PCC with a substantial addition of acrylic or SBR polymer emulsion, most of the pores are filled with polymer; this tends to reduce shrinkage, make the concrete more stable against moisture-related effects, and make it less brittle. Using acrylic latex concrete for thin-shell roofs is described [http://ceae.colorado.edu/mc-edc/pdf/Acrylic%20Concrete%20Roofs.pdf here]. [https://wiki.opensourceecology.org/images/e/ef/Mastercast-141-tds.pdf Rheomix 141], a styrene-butadiene copolymer, has also been recommended for that application. It seems likely that one of these admixtures would considerably improve the stability of a cast-concrete machine base.

== Steel reinforcement ==

PCC is strong in compression but much weaker in tension. The loads on a machine frame will typically put some parts of the frame in tension, and these parts must be reinforced. The simplest support is to cast reinforcing bar (rebar) into the concrete mass. While rebar makes the section strong, it also, ironically, is almost certain to make it filled with small cracks. This is because the concrete sets and locks to the rebar long before it finishes shrinking[https://wiki.opensourceecology.org/images/8/8c/ACI_224R-01_Control_of_Cracking_in_Concrete_Structures_f224R%2801%29Chap3.pdf]:<br>[[File:Cracking.png |border]]<br>'''Figure: Crack development during curing of concrete with embedded steel reinforcement bar'''

To avoid this, the concrete should use ''post-tensioned'' steel reinforcement. By maintaining the concrete always in compression, and never above 30% of the ultimate compressive stress limit, the concrete microstructure will remain quite stable[http://www.cv.titech.ac.jp/~courses/atce1/dim_stab.pdf],[http://people.ce.gatech.edu/~kk92/grad/dim.pdf].

== Recommendations ==

To obtain a dimensionally stable frame, the following steps are recommended:
* Use aggregrate crushed from a dense, stable mineral, preferably granite, limestone, or quartz.
* Post-tension the assembly after ~4 weeks cure
* Paint all surfaces after ~90 days cure
** Might be possible to paint sooner; TBD
** The paint should provide a vapor barrier. In concrete-sealing parlance this requires a "pore-blocker" or barrier treatment, such as epoxy or HMWM (High molecular weight methacrylate), ''not'' a breathable water repellant such as silane or siloxane.
** There is a huge variety of concrete sealing products being sold but little hard information on what works best as a vapor barrier (and whether it works any better than asphaltic mastic or a standard wall paint).

<div id="HolographyTable"></div>These folks wanted stability (world's largest laser holography table[http://smartec.ch/HTMLFiles/Concrete_holography_table_IMM.htm]) and got this:<br>[[File:Shrinkage.png |border]]<br>
The stability reached after 120 days (~ +/-0.2mm over 20m, ~1e-5) is very promising for a machine tool application. The authors ascribe the residual dimensional changes to seasonal temperature variation.

==GVCS applications==

*{{Lathe}}
* {{Steam Engine}}

File:Mastercast-141-tds.pdf

2021-07-25T22:02:23Z

ChuckH: Mastercast (Rheomix) 141 concrete additive

Mastercast (Rheomix) 141 concrete additive

StableConcrete

2021-07-25T21:53:13Z

ChuckH:

= Stable Concrete for Machine Frames =

In a general sense, "concrete" refers to a combination of aggregate (stone, gravel, sand, etc) and a binder (portland cement, epoxy, etc) which hardens into a solid mass. Everyday construction concrete, PCC (Portland Cement Concrete), is based on [[Wikipedia:portland cement|portland cement]]. "Polymer concrete" uses polymer resin (e.g. epoxy), instead of cement, to hold the aggregate together.

Concrete is an attractive material for machine tool frames because
* it is moderately stiff (though much less stiff than cast metals)
* it absorbs vibration well
* it is very east to cast into arbitrary shapes
* it is low cost

Machine tool frames made of PCC date at least as far back as the [https://www.engineeringforchange.org/news/2011/07/31/the_concrete_lathe_world_war_i_technology_meets_21st_century_design.html Yeoman lathe], (see also [http://www.google.com/patents/US3800636 Zagar]) but have never been widely adopted.
In contrast, since the 1980s, polymer concrete has become quite popular in construction of precision machine tools, first in Europe and now worldwide [http://www.americanmachinist.com/304/Issue/Article/False/80845/Issue]. The first commercially important concrete for this purpose was the epoxy-granite composite [http://www.adgrind.com/Studer/Granitan/granitan.htm Granitan], made by the Swiss grinding-machine manufacturer Studer.

Polymer concretes have much better dimensional stability than PCC. [http://books.google.com/books?id=uG7aqgal65YC&pg=PA317#v=onepage&q&f=false Slocum] declares PCC unsatisfactory for precision machinery due to:
* reaction shrinkage from cement hydration
* shrinkage due loss of excess nonstoichiometric water, which leaves conduits for humidity-induced expansion or contraction, and
* non-elastic dimensional changes (e.g. creep and microcracking in the inherent brittle/porous structure).
A [http://dx.doi.org/10.1016/0141-6359(85)90041-8 scientific paper] comparing PCC and polymer concretes in machine tool applications was published by a Studer researcher in 1985. Another article [http://dx.doi.org/10.1016/S0007-8506(07)61657-6 here].

While polymer concrete provides one route to resolving these PCC problems, it is much more costly than PCC and is less compatible with the OSE requirements. It is worth revisiting the application of "plain old concrete" to machine frames with an eye to ameliorate its known weaknesses. Some results cited [[#HolographyTable|below]] suggest that with adequate curing time, surface painting to suppress humidity exchange, and post-tensioned reinforcement, PCC can provide excellent stability.

== PCC shrinkage behavior ==

PCC shrinkage during cure is 0.04 - 0.1%, and shrinkage continues at slower and slower rate for months or years. It is necessary to be patient -- probably waiting 1 to 3 months before considering the concrete dimensionally stable. TBD: do thinner sections stabilize more quickly, and if so, how much?

After the curing process is essentially finished, the concrete remains humidity-sensitive, a bit like wood -- expanding in high humidity and contracting when air is dryer. Concrete also responds to temperature: it has a thermal expansion coefficient close to that of steel. Sealing the surface with paint or similar coating can greatly reduce humidity effects. (This should also reduce carbon dioxide absorption, which causes an additional shrinkage chemical reaction: carbonation.)

In "latex concrete", which is PCC with a substantial addition of acrylic or SBR polymer emulsion, most of the pores are filled with polymer; this tends to reduce shrinkage, make the concrete more stable against moisture-related effects, and make it less brittle. Using acrylic latex concrete for thin-shell roofs is described [http://ceae.colorado.edu/mc-edc/pdf/Acrylic%20Concrete%20Roofs.pdf here]. [http://www.basf-cc.ae/en/products/Mortar/Rheomix141/Pages/default.aspx Rheomix 141], a styrene-butadiene copolymer, has also been recommended for that application. It seems likely that one of these admixtures would considerably improve the stability of a cast-concrete machine base.

== Steel reinforcement ==

PCC is strong in compression but much weaker in tension. The loads on a machine frame will typically put some parts of the frame in tension, and these parts must be reinforced. The simplest support is to cast reinforcing bar (rebar) into the concrete mass. While rebar makes the section strong, it also, ironically, is almost certain to make it filled with small cracks. This is because the concrete sets and locks to the rebar long before it finishes shrinking[https://wiki.opensourceecology.org/images/8/8c/ACI_224R-01_Control_of_Cracking_in_Concrete_Structures_f224R%2801%29Chap3.pdf]:<br>[[File:Cracking.png |border]]<br>'''Figure: Crack development during curing of concrete with embedded steel reinforcement bar'''

To avoid this, the concrete should use ''post-tensioned'' steel reinforcement. By maintaining the concrete always in compression, and never above 30% of the ultimate compressive stress limit, the concrete microstructure will remain quite stable[http://www.cv.titech.ac.jp/~courses/atce1/dim_stab.pdf],[http://people.ce.gatech.edu/~kk92/grad/dim.pdf].

== Recommendations ==

To obtain a dimensionally stable frame, the following steps are recommended:
* Use aggregrate crushed from a dense, stable mineral, preferably granite, limestone, or quartz.
* Post-tension the assembly after ~4 weeks cure
* Paint all surfaces after ~90 days cure
** Might be possible to paint sooner; TBD
** The paint should provide a vapor barrier. In concrete-sealing parlance this requires a "pore-blocker" or barrier treatment, such as epoxy or HMWM (High molecular weight methacrylate), ''not'' a breathable water repellant such as silane or siloxane.
** There is a huge variety of concrete sealing products being sold but little hard information on what works best as a vapor barrier (and whether it works any better than asphaltic mastic or a standard wall paint).

<div id="HolographyTable"></div>These folks wanted stability (world's largest laser holography table[http://smartec.ch/HTMLFiles/Concrete_holography_table_IMM.htm]) and got this:<br>[[File:Shrinkage.png |border]]<br>
The stability reached after 120 days (~ +/-0.2mm over 20m, ~1e-5) is very promising for a machine tool application. The authors ascribe the residual dimensional changes to seasonal temperature variation.

==GVCS applications==

*{{Lathe}}
* {{Steam Engine}}

File:ACI 224R-01 Control of Cracking in Concrete Structures f224R(01)Chap3.pdf

2021-07-25T21:49:24Z

ChuckH: about concrete cracking

about concrete cracking

Induction Furnace Overview

2018-10-15T21:10:52Z

ChuckH: /* Resonating Capacitors */

{{Template:Category=Induction furnace}}
==Overview==
{{Induction Furnace}}

==Introduction==

The Open Source Induction Furnace Project seems to be the most promising way to implement the [[foundry]].
This project involves the design of:
* a high-power induction furnace circuit (between 20 and 50 kW), and
* the melting chamber proper

==test==
Well, we could buy a turnkey system perhaps for $5k total used, and run it from the LifeTrac generator. The only disadvantage to this route is that if it breaks we’re dead-in-the-water – either with the impossibility of fixing closed-source technology, or a high repair bill. A single component which blows and is inaccessible for fixing could in principle turn a working power supply into worthless junk. Thus, it is worthwhile to tame this technology by open-sourcing the design.

===Goals===

To fulfill our [[foundry]] goals,
The furnace should have the following characteristics:

#Induction furnace or any other technology that can do this within a budget of 40 kW of electric input, with minimal pollution
#Suitable for melting all metals and alloying
#150 lb per hour steel melting furnace for casting
#240 v ac, 40 kW power source available

(This spec implies ~260watt-hr/lb, which may be optimistic -- see [[Induction_Furnace_Overview#Melt_Calculations |Melt calculations]])

==Conceptual Diagram==

This is a conceptual diagram of the entire Induction Furnace system from the [[Global Village Construction Set]]. The furnace is powered by 20 kW of 240VAC electricity from the [[LifeTrac]] generator. The entire system includes the power electronics, induction coil, and heating vessel - into which metal for melting is inserted. This diagram intends to document the relationship of functional components in the induction furnace system, as a basis for technical development of components and their integration.

The electronics part should be adaptable to different metals and different metal melting coil geometries. Melting coils should also be modular, such that the power electronics can feed different coils. Basic functions include selection of heating frequencies, which are required for melting different metals or metal geometries. There should be a feedback in the electronics, where the amount of power given to the coil should match the quantity/geometry of metal being melted.

[[Image:induction_concept.jpg]]

==Details==
The complete design should include all of the following:

===Induction Furnace Circuit===
# Scalable from 20 up to 50 kW (perhaps even more)in units of 1 or 5 kW
# Allows for power and frequency range selection for different materials and heating devices
## small crucibles ~50kW, ~1kHz
## heat treating small parts ~5kW, ~100kHz
# Incorporates self-tuning to track the coil resonance dynamically during operation
# Power source may be either 1 or 3 phase electrical power
See also [[Induction_Furnace_Overview#Power_Supply |Power Supply Notes]] below.

===Heat Dissipation System===
Specifications of a cooling or heat dissipation system.

===Coil===
# Modular, adaptable design specifications for primary coil windings
Water-cooled copper tubing coil. Compute skin depth at operating frequency in order to estimate useful thickness of copper section.

=== Yoke ===

In lower frequency furnaces, a laminated iron yoke surrounds the coil, forming part of the magnetic circuit, increasing coil power factor, and thus improving efficiency. The yoke also mechanically resists the large radial forces from the coil. See the useful description of the art in [http://www.google.com/patents/US5247539 US Pat. 5247539]

Steel laminations begin to have high losses at the 1kHz frequency level and soft magnetic composites (e.g. iron powder [http://www.hoganas.com/Segments/Somaloy-Technology/Home/ Somaloy]) might be considered. The biggest problem seems to be that the powder needs to be compressed at 20-50 tons/sq in in order to get good magnetic properties. A bit much for the CEB! Also poweder cost is unknown.

I also looked briefly at steel wire for the yoke but [http://www.pmt.usp.br/academic/landgraf/nossos%20artigos%20em%20pdf/03lan%20smm%20mag%20wire.pdf this paper] was not encouraging.

===Resonating Capacitors===
Modular capacitor bank to accommodate different coil inductances and operating frequencies in different applications.

Induction heating capacitors carry high currents and larger sizes are usually water-cooled to deal with their internal heating. Typically polypropylene is the primary dielectric (due to its low loss factor), combined with dielectric oil and sometimes an additional kraft paper layer. Commercial suppliers of capacitors: [[http://www.celem.com/ Celem]] [[http://www.geindustrial.com/publibrary/checkout/Material%20Safety%20Data%20Sheets%7CIHM_design_aid%7CPDF GE]]

If these high-power capacitors are to be made of local materials, the DIY Tesla coil community (e.g. [http://4hv.org/e107_plugins/forum/forum_viewtopic.php?60477], [http://wiki.4hv.org/index.php/Rolled_foil_capacitor_-_60_kV,_3.5_nF]) may have useful experience.
For oil-filled-paper designs, castor oil has a long history in HV pulse applications and canola[http://www.petroferm.com/datasheets/357_TDS.pdf] oil has become commercially accepted for power frequency applications. ([[Vegetable_Oil_Production |Canola oil]] is also a likely candidate for [[Hydraulic_Fluid |hydraulic fluid]].) Oil/paper may have dielectric loss factor ~1% (as opposed to polypropylene ~0.05%) so internal heating is a major concern and effective cooling is important. Thermal runaway is possible as loss factor increases with dielectric temperature.

===Melt Chamber===
# Geometical design of melt chamber and basic power transfer calculations
# Should include provisions for loading and pouring
# Given our goals, which is best: a coreless or a channel induction furnace type [http://www.wisegeek.com/what-is-an-induction-furnace.htm] ?
## channel: useful in the melting of lower melt temperature metals; less turbulence at the surface.
## coreless: stronger stirring, simpler crucible construction, most commonly used for induction scrap melting
# Pouring: manual pouring methods are more suited to low volume production lines.
====Crucible====
[[File:FirebrickTemps.png |thumb|Firebrick melting point vs Alumina:Silica composition]]
The crucible is made of refractory ceramic which resists the high temperatures of the melt. Even the best materials erode in use, and crucibles must be replaced on a regular basis. An induction furnace crucible may be either
# separately manufactured, fired in a kiln, and subsequently installed in the furnace, or
# formed in place, and sintered (fired) in the induction furnace itself

'''Materials'''

According to this [http://www.foseco.com/en-gb/end-markets/foundry/foseco-home-uk/ Foseco refractories] brochure[http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf], [[File:Furnace-linings-ferrous-01.pdf]] steel foundry induction-furnace applications typically use alumina or magnesia refractories, while cast-iron foundries use high purity silica. This is related to acid/base chemistry of the melt.

Fireclay (which can be a natural alumina/silica clay) for making refractory crucibles must withstand the superheated molten steel temperature of >3000F. Fireclay [http://www.mineralszone.com/minerals/fire-clay.html] is temperature-rated by Pyrometric Cone Equivalent (PCE) [http://www.ortonceramic.com/resources/reference/cone_ref.shtml]; "High Duty" (>= PCE32) or "Super Duty" (>= PCE35) is needed for ferrous metals. Such fireclay has high alumina content. (See also [[Aluminum_Extractor/Research_Development |Aluminum Extractor]] feedstock.)

Some worthwhile DIY fireclay/firebrick information [http://www.traditionaloven.com/articles/101/what-is-fire-clay-and-where-to-get-it here]

'''Separately made crucible'''
* See: [http://www.engineeredceramics.com/products/crucibles-and-ladle-liners.html Engineered Ceramics Service Guides]
<html><iframe width="320" height="240" src="//www.youtube.com/embed/jEKjLSz1ATw?feature=player_embedded" frameborder="0" allowfullscreen></iframe></html>
* DIY small crucible video [http://www.youtube.com/watch?v=E3my6-nxFjM&feature=player_detailpage]<br>

'''Sintered-in-place crucible'''

The materials described in the [http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf Foseco brocure] cited above are "dry-vibratable", meaning they are powders, rammed into place in situ, and sintered in the furnace itself, rather than being seperately made, kiln-fired crucibles. The refractory is rammed against a hollow steel internal ''former'' which defines the inside surface of the crucible. During the first power application, the former transfers sintering heat to the refractory, then either
* is melted away with the first heat leaving a fully-sintered lining[http://www.atlasfdry.com/inductionfurnaces.htm], or
* gets removed at a lower temperature, allowing re-use[http://www.dhanaprakash.com/product.php?nm=lp1&disc=ladleinductionfur.txt&type=Induction%20Furnace%20Removable%20Former%20Sintering&typeid=19&colorbg=6], with final sintering completed by gas flame before the first melting run

===Other Considerations===
# Complete bill of materials
# Fabrication files for circuit and other components
# Sourcing information for components
# System design and process flow drawings

==Notes==
===Benny===
I just read that you plan to build up an induction furnace. That´s a an interesting and exciting plan.While reading the article some remarks came to my mind.

But before I want to introduce myself:

I am Benny from Germany, Hannover.
I am diploma engineer for electrotechnology and working at the university. I am dealing with some induction heating/ melting applications like induction melting of glasses (that is possible!) and induction furnaces for cast iron.

Some remarks from my point of view:

# It is possible to build up a low cost furnace with the mentioned parameters.
# The frequency of 9,6 kHz is much to high. The efficiancy will be so bad, that it will be hardly possible to melt steel or iron. Due to the small penetration depth of about 2 mm with this frequency and this electrical resistance. So it needs a really small diameter of the crucible, and thats not helpful. Also the refractory material will be strained too much, so that a small lifetime is given. This will raise the cost for the operating.
# 50 Hz or 60 Hz is a better solution. And you can save the cost for the hf-converter.
# How much material do you want to cast at one time? The maximum, what i expect to be possible with 50 kW will be about 50 to 60 kg.
# What kind of raw material should be charged? It is important for the starting, because the initial density should not be too small (packing density). And the other question is, what kind of scrap it will be.
There are so many problems known with content of zinc (hot zinc dipped) and other materials. The lifetime of common refractory material is really small. And what is more important the security for the personal is not given without a strong exhaust system, due to the toxic steam. I expect this as a strong cost factor.

===Power Supply===
There are two approaches to providing the single-phase high-frequency AC power required by the induction furnace coil
* Electronic converter ([[Universal_Power_Supply |Universal Power Supply]])
** Wide frequency tunability possible - including very high frequencies for heat treating small parts
** Dynamic auto-tuning to coil resonance using established phase detector control methods
** power source: DC from [[Battery |battery]] storage banks
** power source: AC from 50/60Hz power
*** Typically the induction furnace power converter then operates AC->DC->AC
*** Preferably 3 phase AC source at higher power levels (better efficiency)
*** 50/60Hz AC can come from battery banks thru DC->AC converter, or from [[Generator |rotary generator]] driven by engine or hydraulic motor

* [[Generator |Rotary generator]]
** Limited frequency range
*** up to ~1kHz with slightly-modified conventional automotive alternator [http://www.venselenterprises.com/techtipsfromdick_files/alternators.pdf][http://www.delcoremy.com/Documents/Electrical-Specifications---Selection-Guide.aspx] (e.g. Delco 30SI 16 pole @ 10000 rpm = 1333Hz), perhaps adequate for crucible melting applications. [http://www.thebackshed.com/windmill/FPRewire.asp Fisher Paykel washing machine motors] are 48- or 56-pole permanent magnet designs often converted to generators and might operate into the low kilohertz range.
*** Commercial induction heating supplies in mid-20th century often used motor-generator sets. Here is a vertical-shaft one rated 50kW 3000 Hz from [https://www.chaski.org/homemachinist/download/file.php?id=59926&mode=view Ajax Magnethermics]
*** [https://patents.google.com/patent/US2451954A Westinghouse high-frequency generator patent] for induction heating, 3kHz, 10kHz examples
*** [https://patents.google.com/patent/US1583809A 15kHz generator patent] (not targeted to induction heating); magnetic structure similar to modern hybrid [[Stepper_motor |stepper motor]]
*** >100kHz historically feasible with [http://en.wikipedia.org/wiki/Alexanderson_alternator Alexanderson reluctance generators]
*** frequency controlled by varying shaft speed: frequency = shaft speed * pole pairs
*** dynamic auto-tuning to coil resonance may be difficult
** Three phase vs single phase
*** most reasonably-efficient rotary generators deliver balanced three-phase power, but an induction furnace is a single-phase load
*** this can be addressed with a simple tuned load balancer [http://www.google.com/patents/US3331909], but this may require manual tap- and capacitor adjustments depending on the load
*** alternatively a solid-state static synchronous compensator (STATCOM) can be applied, as described for example in [http://www.strutherstech.com/PDF/STATCOM%20LOAD%20BALANCING.pdf]
*** a combination of the above two methods (carrying most of the load unbalance with fixed capacitors/reactors and using a relatively low-VAR static compensator) might be most economical
** Mechanical power source
*** electric motor (motor-generator set)
*** prime mover (internal combustion or [[Steam_Engine |steam engine]])
*** hydraulic
**** [[Power_Cube |Power Cube]]
**** [[Stationary_Hydraulic_Power |Stationary hydraulic power]]
**** shaft speed control by variable displacement motor or [[Stationary_Hydraulic_Power#Hydraulic_pressure_transformation |hydraulic transformer]]

----
*50 kW for $1600 - [http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200415768835&rvr_id=&crlp=1_263602_263622&UA=L*F%3F&GUID=1357ab741250a0265337bec7ff94d6a7&itemid=200415768835&ff4=263602_263622]
*20 kw STC 3 phase 120 - 480V, also 1 phase - generator - $692 -[http://cgi.ebay.com/20kw-STC-3-Phase-277-480-12-Wire-generator-Head-altern_W0QQitemZ160369799644QQcmdZViewItemQQptZBI_Generators?hash=item2556c8f1dc]
*50 kw STC 3 phase- $1300 - [http://cgi.ebay.com/50KW-STC-3-Phase-12-Wire-generator-alternator_W0QQitemZ160357088416QQcmdZViewItemQQptZBI_Generators?hash=item255606fca0]
**LifeTrac 55 hp can produce 38 kW with this head

===Melt Calculations===
[[Image:inductioncalc.jpg]]

''Note:'' Electrical input requirements may be reduced somewhat by preheating the charge with flame or direct solar energy.

[[Image:imgp4545.jpg|600px]]

Photo I took while visiting a foundry near Santa Fe. Seems relevant!

==Wiki Links==

*[[Foundry]]

*[[Induction Furnace Request for Bids]]

==External Links==
* [http://blog.opensourceecology.org/?p=1373 Original Blog Post]
* [http://web.archive.org/web/20100816034057/http://www.uie.org/webfm_send/391 Technical basics and applications of induction furnace PDF]

==See Also==
{{Induction Furnace}}

[[Category:Induction_Furnace]]

Induction Furnace Overview

2018-10-15T20:52:32Z

ChuckH: /* Power Supply */

{{Template:Category=Induction furnace}}
==Overview==
{{Induction Furnace}}

==Introduction==

The Open Source Induction Furnace Project seems to be the most promising way to implement the [[foundry]].
This project involves the design of:
* a high-power induction furnace circuit (between 20 and 50 kW), and
* the melting chamber proper

==test==
Well, we could buy a turnkey system perhaps for $5k total used, and run it from the LifeTrac generator. The only disadvantage to this route is that if it breaks we’re dead-in-the-water – either with the impossibility of fixing closed-source technology, or a high repair bill. A single component which blows and is inaccessible for fixing could in principle turn a working power supply into worthless junk. Thus, it is worthwhile to tame this technology by open-sourcing the design.

===Goals===

To fulfill our [[foundry]] goals,
The furnace should have the following characteristics:

#Induction furnace or any other technology that can do this within a budget of 40 kW of electric input, with minimal pollution
#Suitable for melting all metals and alloying
#150 lb per hour steel melting furnace for casting
#240 v ac, 40 kW power source available

(This spec implies ~260watt-hr/lb, which may be optimistic -- see [[Induction_Furnace_Overview#Melt_Calculations |Melt calculations]])

==Conceptual Diagram==

This is a conceptual diagram of the entire Induction Furnace system from the [[Global Village Construction Set]]. The furnace is powered by 20 kW of 240VAC electricity from the [[LifeTrac]] generator. The entire system includes the power electronics, induction coil, and heating vessel - into which metal for melting is inserted. This diagram intends to document the relationship of functional components in the induction furnace system, as a basis for technical development of components and their integration.

The electronics part should be adaptable to different metals and different metal melting coil geometries. Melting coils should also be modular, such that the power electronics can feed different coils. Basic functions include selection of heating frequencies, which are required for melting different metals or metal geometries. There should be a feedback in the electronics, where the amount of power given to the coil should match the quantity/geometry of metal being melted.

[[Image:induction_concept.jpg]]

==Details==
The complete design should include all of the following:

===Induction Furnace Circuit===
# Scalable from 20 up to 50 kW (perhaps even more)in units of 1 or 5 kW
# Allows for power and frequency range selection for different materials and heating devices
## small crucibles ~50kW, ~1kHz
## heat treating small parts ~5kW, ~100kHz
# Incorporates self-tuning to track the coil resonance dynamically during operation
# Power source may be either 1 or 3 phase electrical power
See also [[Induction_Furnace_Overview#Power_Supply |Power Supply Notes]] below.

===Heat Dissipation System===
Specifications of a cooling or heat dissipation system.

===Coil===
# Modular, adaptable design specifications for primary coil windings
Water-cooled copper tubing coil. Compute skin depth at operating frequency in order to estimate useful thickness of copper section.

=== Yoke ===

In lower frequency furnaces, a laminated iron yoke surrounds the coil, forming part of the magnetic circuit, increasing coil power factor, and thus improving efficiency. The yoke also mechanically resists the large radial forces from the coil. See the useful description of the art in [http://www.google.com/patents/US5247539 US Pat. 5247539]

Steel laminations begin to have high losses at the 1kHz frequency level and soft magnetic composites (e.g. iron powder [http://www.hoganas.com/Segments/Somaloy-Technology/Home/ Somaloy]) might be considered. The biggest problem seems to be that the powder needs to be compressed at 20-50 tons/sq in in order to get good magnetic properties. A bit much for the CEB! Also poweder cost is unknown.

I also looked briefly at steel wire for the yoke but [http://www.pmt.usp.br/academic/landgraf/nossos%20artigos%20em%20pdf/03lan%20smm%20mag%20wire.pdf this paper] was not encouraging.

===Resonating Capacitors===
Modular capacitor bank to accommodate different coil inductances and operating frequencies in different applications.

Induction heating capacitors carry high currents and larger sizes are usually water-cooled to deal with their internal heating. Typically polypropylene is the primary dielectric (due to its low loss factor), combined with dielectric oil and sometimes an additional kraft paper layer. Commercial suppliers of capacitors: [[http://www.celem.com/ Celem]] [[http://www.geindustrial.com/publibrary/checkout/Material%20Safety%20Data%20Sheets%7CIHM_design_aid%7CPDF GE]]

If these high-power capacitors are to be made of local materials, the DIY Tesla coil community (e.g. [http://4hv.org/e107_plugins/forum/forum_viewtopic.php?60477], [http://wiki.4hv.org/index.php/Rolled_foil_capacitor_-_60_kV,_3.5_nF]) may have useful experience.
For oil-filled-paper designs, castor oil has a long history in HV pulse applications and canola[http://www.petroferm.com/datasheets/357_TDS.pdf] oil has become commercially accepted for power frequency applications. ([[Vegetable_Oil_Production |Canola oil]] is also a likely candidate for [[Hydraulic_Fluid |hydraulic fluid]].) Oil/paper may have dielectric loss factor ~1% (as opposed to polypropylene ~0.05%) so pay attention to internal heating.

===Melt Chamber===
# Geometical design of melt chamber and basic power transfer calculations
# Should include provisions for loading and pouring
# Given our goals, which is best: a coreless or a channel induction furnace type [http://www.wisegeek.com/what-is-an-induction-furnace.htm] ?
## channel: useful in the melting of lower melt temperature metals; less turbulence at the surface.
## coreless: stronger stirring, simpler crucible construction, most commonly used for induction scrap melting
# Pouring: manual pouring methods are more suited to low volume production lines.
====Crucible====
[[File:FirebrickTemps.png |thumb|Firebrick melting point vs Alumina:Silica composition]]
The crucible is made of refractory ceramic which resists the high temperatures of the melt. Even the best materials erode in use, and crucibles must be replaced on a regular basis. An induction furnace crucible may be either
# separately manufactured, fired in a kiln, and subsequently installed in the furnace, or
# formed in place, and sintered (fired) in the induction furnace itself

'''Materials'''

According to this [http://www.foseco.com/en-gb/end-markets/foundry/foseco-home-uk/ Foseco refractories] brochure[http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf], [[File:Furnace-linings-ferrous-01.pdf]] steel foundry induction-furnace applications typically use alumina or magnesia refractories, while cast-iron foundries use high purity silica. This is related to acid/base chemistry of the melt.

Fireclay (which can be a natural alumina/silica clay) for making refractory crucibles must withstand the superheated molten steel temperature of >3000F. Fireclay [http://www.mineralszone.com/minerals/fire-clay.html] is temperature-rated by Pyrometric Cone Equivalent (PCE) [http://www.ortonceramic.com/resources/reference/cone_ref.shtml]; "High Duty" (>= PCE32) or "Super Duty" (>= PCE35) is needed for ferrous metals. Such fireclay has high alumina content. (See also [[Aluminum_Extractor/Research_Development |Aluminum Extractor]] feedstock.)

Some worthwhile DIY fireclay/firebrick information [http://www.traditionaloven.com/articles/101/what-is-fire-clay-and-where-to-get-it here]

'''Separately made crucible'''
* See: [http://www.engineeredceramics.com/products/crucibles-and-ladle-liners.html Engineered Ceramics Service Guides]
<html><iframe width="320" height="240" src="//www.youtube.com/embed/jEKjLSz1ATw?feature=player_embedded" frameborder="0" allowfullscreen></iframe></html>
* DIY small crucible video [http://www.youtube.com/watch?v=E3my6-nxFjM&feature=player_detailpage]<br>

'''Sintered-in-place crucible'''

The materials described in the [http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf Foseco brocure] cited above are "dry-vibratable", meaning they are powders, rammed into place in situ, and sintered in the furnace itself, rather than being seperately made, kiln-fired crucibles. The refractory is rammed against a hollow steel internal ''former'' which defines the inside surface of the crucible. During the first power application, the former transfers sintering heat to the refractory, then either
* is melted away with the first heat leaving a fully-sintered lining[http://www.atlasfdry.com/inductionfurnaces.htm], or
* gets removed at a lower temperature, allowing re-use[http://www.dhanaprakash.com/product.php?nm=lp1&disc=ladleinductionfur.txt&type=Induction%20Furnace%20Removable%20Former%20Sintering&typeid=19&colorbg=6], with final sintering completed by gas flame before the first melting run

===Other Considerations===
# Complete bill of materials
# Fabrication files for circuit and other components
# Sourcing information for components
# System design and process flow drawings

==Notes==
===Benny===
I just read that you plan to build up an induction furnace. That´s a an interesting and exciting plan.While reading the article some remarks came to my mind.

But before I want to introduce myself:

I am Benny from Germany, Hannover.
I am diploma engineer for electrotechnology and working at the university. I am dealing with some induction heating/ melting applications like induction melting of glasses (that is possible!) and induction furnaces for cast iron.

Some remarks from my point of view:

# It is possible to build up a low cost furnace with the mentioned parameters.
# The frequency of 9,6 kHz is much to high. The efficiancy will be so bad, that it will be hardly possible to melt steel or iron. Due to the small penetration depth of about 2 mm with this frequency and this electrical resistance. So it needs a really small diameter of the crucible, and thats not helpful. Also the refractory material will be strained too much, so that a small lifetime is given. This will raise the cost for the operating.
# 50 Hz or 60 Hz is a better solution. And you can save the cost for the hf-converter.
# How much material do you want to cast at one time? The maximum, what i expect to be possible with 50 kW will be about 50 to 60 kg.
# What kind of raw material should be charged? It is important for the starting, because the initial density should not be too small (packing density). And the other question is, what kind of scrap it will be.
There are so many problems known with content of zinc (hot zinc dipped) and other materials. The lifetime of common refractory material is really small. And what is more important the security for the personal is not given without a strong exhaust system, due to the toxic steam. I expect this as a strong cost factor.

===Power Supply===
There are two approaches to providing the single-phase high-frequency AC power required by the induction furnace coil
* Electronic converter ([[Universal_Power_Supply |Universal Power Supply]])
** Wide frequency tunability possible - including very high frequencies for heat treating small parts
** Dynamic auto-tuning to coil resonance using established phase detector control methods
** power source: DC from [[Battery |battery]] storage banks
** power source: AC from 50/60Hz power
*** Typically the induction furnace power converter then operates AC->DC->AC
*** Preferably 3 phase AC source at higher power levels (better efficiency)
*** 50/60Hz AC can come from battery banks thru DC->AC converter, or from [[Generator |rotary generator]] driven by engine or hydraulic motor

* [[Generator |Rotary generator]]
** Limited frequency range
*** up to ~1kHz with slightly-modified conventional automotive alternator [http://www.venselenterprises.com/techtipsfromdick_files/alternators.pdf][http://www.delcoremy.com/Documents/Electrical-Specifications---Selection-Guide.aspx] (e.g. Delco 30SI 16 pole @ 10000 rpm = 1333Hz), perhaps adequate for crucible melting applications. [http://www.thebackshed.com/windmill/FPRewire.asp Fisher Paykel washing machine motors] are 48- or 56-pole permanent magnet designs often converted to generators and might operate into the low kilohertz range.
*** Commercial induction heating supplies in mid-20th century often used motor-generator sets. Here is a vertical-shaft one rated 50kW 3000 Hz from [https://www.chaski.org/homemachinist/download/file.php?id=59926&mode=view Ajax Magnethermics]
*** [https://patents.google.com/patent/US2451954A Westinghouse high-frequency generator patent] for induction heating, 3kHz, 10kHz examples
*** [https://patents.google.com/patent/US1583809A 15kHz generator patent] (not targeted to induction heating); magnetic structure similar to modern hybrid [[Stepper_motor |stepper motor]]
*** >100kHz historically feasible with [http://en.wikipedia.org/wiki/Alexanderson_alternator Alexanderson reluctance generators]
*** frequency controlled by varying shaft speed: frequency = shaft speed * pole pairs
*** dynamic auto-tuning to coil resonance may be difficult
** Three phase vs single phase
*** most reasonably-efficient rotary generators deliver balanced three-phase power, but an induction furnace is a single-phase load
*** this can be addressed with a simple tuned load balancer [http://www.google.com/patents/US3331909], but this may require manual tap- and capacitor adjustments depending on the load
*** alternatively a solid-state static synchronous compensator (STATCOM) can be applied, as described for example in [http://www.strutherstech.com/PDF/STATCOM%20LOAD%20BALANCING.pdf]
*** a combination of the above two methods (carrying most of the load unbalance with fixed capacitors/reactors and using a relatively low-VAR static compensator) might be most economical
** Mechanical power source
*** electric motor (motor-generator set)
*** prime mover (internal combustion or [[Steam_Engine |steam engine]])
*** hydraulic
**** [[Power_Cube |Power Cube]]
**** [[Stationary_Hydraulic_Power |Stationary hydraulic power]]
**** shaft speed control by variable displacement motor or [[Stationary_Hydraulic_Power#Hydraulic_pressure_transformation |hydraulic transformer]]

----
*50 kW for $1600 - [http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200415768835&rvr_id=&crlp=1_263602_263622&UA=L*F%3F&GUID=1357ab741250a0265337bec7ff94d6a7&itemid=200415768835&ff4=263602_263622]
*20 kw STC 3 phase 120 - 480V, also 1 phase - generator - $692 -[http://cgi.ebay.com/20kw-STC-3-Phase-277-480-12-Wire-generator-Head-altern_W0QQitemZ160369799644QQcmdZViewItemQQptZBI_Generators?hash=item2556c8f1dc]
*50 kw STC 3 phase- $1300 - [http://cgi.ebay.com/50KW-STC-3-Phase-12-Wire-generator-alternator_W0QQitemZ160357088416QQcmdZViewItemQQptZBI_Generators?hash=item255606fca0]
**LifeTrac 55 hp can produce 38 kW with this head

===Melt Calculations===
[[Image:inductioncalc.jpg]]

''Note:'' Electrical input requirements may be reduced somewhat by preheating the charge with flame or direct solar energy.

[[Image:imgp4545.jpg|600px]]

Photo I took while visiting a foundry near Santa Fe. Seems relevant!

==Wiki Links==

*[[Foundry]]

*[[Induction Furnace Request for Bids]]

==External Links==
* [http://blog.opensourceecology.org/?p=1373 Original Blog Post]
* [http://web.archive.org/web/20100816034057/http://www.uie.org/webfm_send/391 Technical basics and applications of induction furnace PDF]

==See Also==
{{Induction Furnace}}

[[Category:Induction_Furnace]]

Induction Furnace Overview

2018-10-15T20:49:12Z

ChuckH: /* Power Supply */

{{Template:Category=Induction furnace}}
==Overview==
{{Induction Furnace}}

==Introduction==

The Open Source Induction Furnace Project seems to be the most promising way to implement the [[foundry]].
This project involves the design of:
* a high-power induction furnace circuit (between 20 and 50 kW), and
* the melting chamber proper

==test==
Well, we could buy a turnkey system perhaps for $5k total used, and run it from the LifeTrac generator. The only disadvantage to this route is that if it breaks we’re dead-in-the-water – either with the impossibility of fixing closed-source technology, or a high repair bill. A single component which blows and is inaccessible for fixing could in principle turn a working power supply into worthless junk. Thus, it is worthwhile to tame this technology by open-sourcing the design.

===Goals===

To fulfill our [[foundry]] goals,
The furnace should have the following characteristics:

#Induction furnace or any other technology that can do this within a budget of 40 kW of electric input, with minimal pollution
#Suitable for melting all metals and alloying
#150 lb per hour steel melting furnace for casting
#240 v ac, 40 kW power source available

(This spec implies ~260watt-hr/lb, which may be optimistic -- see [[Induction_Furnace_Overview#Melt_Calculations |Melt calculations]])

==Conceptual Diagram==

This is a conceptual diagram of the entire Induction Furnace system from the [[Global Village Construction Set]]. The furnace is powered by 20 kW of 240VAC electricity from the [[LifeTrac]] generator. The entire system includes the power electronics, induction coil, and heating vessel - into which metal for melting is inserted. This diagram intends to document the relationship of functional components in the induction furnace system, as a basis for technical development of components and their integration.

The electronics part should be adaptable to different metals and different metal melting coil geometries. Melting coils should also be modular, such that the power electronics can feed different coils. Basic functions include selection of heating frequencies, which are required for melting different metals or metal geometries. There should be a feedback in the electronics, where the amount of power given to the coil should match the quantity/geometry of metal being melted.

[[Image:induction_concept.jpg]]

==Details==
The complete design should include all of the following:

===Induction Furnace Circuit===
# Scalable from 20 up to 50 kW (perhaps even more)in units of 1 or 5 kW
# Allows for power and frequency range selection for different materials and heating devices
## small crucibles ~50kW, ~1kHz
## heat treating small parts ~5kW, ~100kHz
# Incorporates self-tuning to track the coil resonance dynamically during operation
# Power source may be either 1 or 3 phase electrical power
See also [[Induction_Furnace_Overview#Power_Supply |Power Supply Notes]] below.

===Heat Dissipation System===
Specifications of a cooling or heat dissipation system.

===Coil===
# Modular, adaptable design specifications for primary coil windings
Water-cooled copper tubing coil. Compute skin depth at operating frequency in order to estimate useful thickness of copper section.

=== Yoke ===

In lower frequency furnaces, a laminated iron yoke surrounds the coil, forming part of the magnetic circuit, increasing coil power factor, and thus improving efficiency. The yoke also mechanically resists the large radial forces from the coil. See the useful description of the art in [http://www.google.com/patents/US5247539 US Pat. 5247539]

Steel laminations begin to have high losses at the 1kHz frequency level and soft magnetic composites (e.g. iron powder [http://www.hoganas.com/Segments/Somaloy-Technology/Home/ Somaloy]) might be considered. The biggest problem seems to be that the powder needs to be compressed at 20-50 tons/sq in in order to get good magnetic properties. A bit much for the CEB! Also poweder cost is unknown.

I also looked briefly at steel wire for the yoke but [http://www.pmt.usp.br/academic/landgraf/nossos%20artigos%20em%20pdf/03lan%20smm%20mag%20wire.pdf this paper] was not encouraging.

===Resonating Capacitors===
Modular capacitor bank to accommodate different coil inductances and operating frequencies in different applications.

Induction heating capacitors carry high currents and larger sizes are usually water-cooled to deal with their internal heating. Typically polypropylene is the primary dielectric (due to its low loss factor), combined with dielectric oil and sometimes an additional kraft paper layer. Commercial suppliers of capacitors: [[http://www.celem.com/ Celem]] [[http://www.geindustrial.com/publibrary/checkout/Material%20Safety%20Data%20Sheets%7CIHM_design_aid%7CPDF GE]]

If these high-power capacitors are to be made of local materials, the DIY Tesla coil community (e.g. [http://4hv.org/e107_plugins/forum/forum_viewtopic.php?60477], [http://wiki.4hv.org/index.php/Rolled_foil_capacitor_-_60_kV,_3.5_nF]) may have useful experience.
For oil-filled-paper designs, castor oil has a long history in HV pulse applications and canola[http://www.petroferm.com/datasheets/357_TDS.pdf] oil has become commercially accepted for power frequency applications. ([[Vegetable_Oil_Production |Canola oil]] is also a likely candidate for [[Hydraulic_Fluid |hydraulic fluid]].) Oil/paper may have dielectric loss factor ~1% (as opposed to polypropylene ~0.05%) so pay attention to internal heating.

===Melt Chamber===
# Geometical design of melt chamber and basic power transfer calculations
# Should include provisions for loading and pouring
# Given our goals, which is best: a coreless or a channel induction furnace type [http://www.wisegeek.com/what-is-an-induction-furnace.htm] ?
## channel: useful in the melting of lower melt temperature metals; less turbulence at the surface.
## coreless: stronger stirring, simpler crucible construction, most commonly used for induction scrap melting
# Pouring: manual pouring methods are more suited to low volume production lines.
====Crucible====
[[File:FirebrickTemps.png |thumb|Firebrick melting point vs Alumina:Silica composition]]
The crucible is made of refractory ceramic which resists the high temperatures of the melt. Even the best materials erode in use, and crucibles must be replaced on a regular basis. An induction furnace crucible may be either
# separately manufactured, fired in a kiln, and subsequently installed in the furnace, or
# formed in place, and sintered (fired) in the induction furnace itself

'''Materials'''

According to this [http://www.foseco.com/en-gb/end-markets/foundry/foseco-home-uk/ Foseco refractories] brochure[http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf], [[File:Furnace-linings-ferrous-01.pdf]] steel foundry induction-furnace applications typically use alumina or magnesia refractories, while cast-iron foundries use high purity silica. This is related to acid/base chemistry of the melt.

Fireclay (which can be a natural alumina/silica clay) for making refractory crucibles must withstand the superheated molten steel temperature of >3000F. Fireclay [http://www.mineralszone.com/minerals/fire-clay.html] is temperature-rated by Pyrometric Cone Equivalent (PCE) [http://www.ortonceramic.com/resources/reference/cone_ref.shtml]; "High Duty" (>= PCE32) or "Super Duty" (>= PCE35) is needed for ferrous metals. Such fireclay has high alumina content. (See also [[Aluminum_Extractor/Research_Development |Aluminum Extractor]] feedstock.)

Some worthwhile DIY fireclay/firebrick information [http://www.traditionaloven.com/articles/101/what-is-fire-clay-and-where-to-get-it here]

'''Separately made crucible'''
* See: [http://www.engineeredceramics.com/products/crucibles-and-ladle-liners.html Engineered Ceramics Service Guides]
<html><iframe width="320" height="240" src="//www.youtube.com/embed/jEKjLSz1ATw?feature=player_embedded" frameborder="0" allowfullscreen></iframe></html>
* DIY small crucible video [http://www.youtube.com/watch?v=E3my6-nxFjM&feature=player_detailpage]<br>

'''Sintered-in-place crucible'''

The materials described in the [http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf Foseco brocure] cited above are "dry-vibratable", meaning they are powders, rammed into place in situ, and sintered in the furnace itself, rather than being seperately made, kiln-fired crucibles. The refractory is rammed against a hollow steel internal ''former'' which defines the inside surface of the crucible. During the first power application, the former transfers sintering heat to the refractory, then either
* is melted away with the first heat leaving a fully-sintered lining[http://www.atlasfdry.com/inductionfurnaces.htm], or
* gets removed at a lower temperature, allowing re-use[http://www.dhanaprakash.com/product.php?nm=lp1&disc=ladleinductionfur.txt&type=Induction%20Furnace%20Removable%20Former%20Sintering&typeid=19&colorbg=6], with final sintering completed by gas flame before the first melting run

===Other Considerations===
# Complete bill of materials
# Fabrication files for circuit and other components
# Sourcing information for components
# System design and process flow drawings

==Notes==
===Benny===
I just read that you plan to build up an induction furnace. That´s a an interesting and exciting plan.While reading the article some remarks came to my mind.

But before I want to introduce myself:

I am Benny from Germany, Hannover.
I am diploma engineer for electrotechnology and working at the university. I am dealing with some induction heating/ melting applications like induction melting of glasses (that is possible!) and induction furnaces for cast iron.

Some remarks from my point of view:

# It is possible to build up a low cost furnace with the mentioned parameters.
# The frequency of 9,6 kHz is much to high. The efficiancy will be so bad, that it will be hardly possible to melt steel or iron. Due to the small penetration depth of about 2 mm with this frequency and this electrical resistance. So it needs a really small diameter of the crucible, and thats not helpful. Also the refractory material will be strained too much, so that a small lifetime is given. This will raise the cost for the operating.
# 50 Hz or 60 Hz is a better solution. And you can save the cost for the hf-converter.
# How much material do you want to cast at one time? The maximum, what i expect to be possible with 50 kW will be about 50 to 60 kg.
# What kind of raw material should be charged? It is important for the starting, because the initial density should not be too small (packing density). And the other question is, what kind of scrap it will be.
There are so many problems known with content of zinc (hot zinc dipped) and other materials. The lifetime of common refractory material is really small. And what is more important the security for the personal is not given without a strong exhaust system, due to the toxic steam. I expect this as a strong cost factor.

===Power Supply===
There are two approaches to providing the single-phase high-frequency AC power required by the induction furnace coil
* Electronic converter ([[Universal_Power_Supply |Universal Power Supply]])
** Wide frequency tunability possible - including very high frequencies for heat treating small parts
** Dynamic auto-tuning to coil resonance using established phase detector control methods
** power source: DC from [[Battery |battery]] storage banks
** power source: AC from 50/60Hz power
*** Typically the induction furnace power converter then operates AC->DC->AC
*** Preferably 3 phase AC source at higher power levels (better efficiency)
*** 50/60Hz AC can come from battery banks thru DC->AC converter, or from [[Generator |rotary generator]] driven by engine or hydraulic motor

* [[Generator |Rotary generator]]
** Limited frequency range
*** up to ~1kHz with slightly-modified conventional automotive alternator [http://www.venselenterprises.com/techtipsfromdick_files/alternators.pdf][http://www.delcoremy.com/Documents/Electrical-Specifications---Selection-Guide.aspx] (e.g. Delco 30SI 16 pole @ 10000 rpm = 1333Hz), perhaps adequate for crucible melting applications. [http://www.thebackshed.com/windmill/FPRewire.asp Fisher Paykel washing machine motors] are 48- or 56-pole permanent magnet designs often converted to generators and might operate into the low kilohertz range.
*** Commercial induction heating supplies in mid-20th century often used motor-generator sets. Here is a vertical-shaft one rated 50kW 3000 Hz from [https://www.chaski.org/homemachinist/download/file.php?id=59926&mode=view Ajax Magnethermics]
*** [https://patents.google.com/patent/US2451954A Westinghouse high-frequency generator patent] for induction heating, 3kHz, 10kHz examples
*** [https://patents.google.com/patent/US1583809A 15kHz generator patent] (not targeted to induction heating); magnetic structure similar to modern hybrid stepper motor
*** >100kHz historically feasible with [http://en.wikipedia.org/wiki/Alexanderson_alternator Alexanderson reluctance generators]
*** frequency controlled by varying shaft speed: frequency = shaft speed * pole pairs
*** dynamic auto-tuning to coil resonance may be difficult
** Three phase vs single phase
*** most reasonably-efficient rotary generators deliver balanced three-phase power, but an induction furnace is a single-phase load
*** this can be addressed with a simple tuned load balancer [http://www.google.com/patents/US3331909], but this may require manual tap- and capacitor adjustments depending on the load
*** alternatively a solid-state static synchronous compensator (STATCOM) can be applied, as described for example in [http://www.strutherstech.com/PDF/STATCOM%20LOAD%20BALANCING.pdf]
*** a combination of the above two methods (carrying most of the load unbalance with fixed capacitors/reactors and using a relatively low-VAR static compensator) might be most economical
** Mechanical power source
*** electric motor (motor-generator set)
*** prime mover (internal combustion or [[Steam_Engine |steam engine]])
*** hydraulic
**** [[Power_Cube |Power Cube]]
**** [[Stationary_Hydraulic_Power |Stationary hydraulic power]]
**** shaft speed control by variable displacement motor or [[Stationary_Hydraulic_Power#Hydraulic_pressure_transformation |hydraulic transformer]]

----
*50 kW for $1600 - [http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200415768835&rvr_id=&crlp=1_263602_263622&UA=L*F%3F&GUID=1357ab741250a0265337bec7ff94d6a7&itemid=200415768835&ff4=263602_263622]
*20 kw STC 3 phase 120 - 480V, also 1 phase - generator - $692 -[http://cgi.ebay.com/20kw-STC-3-Phase-277-480-12-Wire-generator-Head-altern_W0QQitemZ160369799644QQcmdZViewItemQQptZBI_Generators?hash=item2556c8f1dc]
*50 kw STC 3 phase- $1300 - [http://cgi.ebay.com/50KW-STC-3-Phase-12-Wire-generator-alternator_W0QQitemZ160357088416QQcmdZViewItemQQptZBI_Generators?hash=item255606fca0]
**LifeTrac 55 hp can produce 38 kW with this head

===Melt Calculations===
[[Image:inductioncalc.jpg]]

''Note:'' Electrical input requirements may be reduced somewhat by preheating the charge with flame or direct solar energy.

[[Image:imgp4545.jpg|600px]]

Photo I took while visiting a foundry near Santa Fe. Seems relevant!

==Wiki Links==

*[[Foundry]]

*[[Induction Furnace Request for Bids]]

==External Links==
* [http://blog.opensourceecology.org/?p=1373 Original Blog Post]
* [http://web.archive.org/web/20100816034057/http://www.uie.org/webfm_send/391 Technical basics and applications of induction furnace PDF]

==See Also==
{{Induction Furnace}}

[[Category:Induction_Furnace]]

Compressed Earth Blocks

2018-10-14T21:16:27Z

ChuckH: /* More Information */

{{OrigLang}} {{RightTOC}}
==Overview==
[[File:Liberator_bricks.JPG|right|400px|thumb|Bricks pressed on [[The Liberator]]]]'''

[[Image:Chrow.jpg|thumb|MicroHouse 2 Build with open source tractor, soil pulverizer, and brick press, April 2014.]]

[[Image:44_cebfab.jpg |thumb|OSE's compressed earth block]]

Compressed Earth Blocks are the main construction material used in the [[GVCS]] [[CEB_Press|Compressed Earth Block Press (formerly called The Liberator)]].

CEB Construction is a powerful technique for empowering communities to produce on-demand housing.

The bricks do not require curing - so a machine may churn out bricks on-site that can be continuously added to the building. CEB lends itself to 100% onsite building material sourcing. The thermal insulation, sound insulation, and strength of the bricks are excellent.

CEBs can also be used in fences, [[CEB Water Cistern|cisterns]], road paving, ovens, dams, thermal storage cisterns, silos, barns, dairy plant, bakery building, [[Greenhouses|greenhouses]], raised garden beds, etc.

==Materials used in compressed earth blocks==
CEBs are made from soil that is 15-40% non-expansive clay, 25-40% silt powder, and 40-70% sharp sand to small gravel content. The more modern machines do not require aggregate (rock) to make a strong soil block for most applications. Soil moisture content ranges from 4-12% by weight. Clay with a plasticity index (PI) of up to 25 or 30 would be acceptable for most applications. The PI of the mixed soil (clay, silt and sand/gravel combined) should not exceed 12 to 15; that is the difference between the Upper and Lower [http://en.wikipedia.org/wiki/Atterberg_limits Atterberg limits], as determined by laboratory testing.<ref>http://en.wikipedia.org/wiki/Compressed_earth_block</ref>

Selection and preparation of the soil are important to getting the best results from a CEB press. See the [[CEB_Blocks |CEB Blocks]] page.

===CEB Shapes and Sizes===
(TODO: Add pictures of CEBs built with The Liberator; show different shapes and sizes it can make)

[[To Interlock on Not to Interlock]]

===Alternative Materials===
* [[Krafterra]]: A researcher from UnB (University of Brasília, Brazil) suggests the use of kraft paper from cement bags mixed with earth to obtain better CEBs, dubbed '''krafterra'''.
* [[Compressed Earth Bricks with Wool|Wool]]
* [[Geopolymers]]: Although cements are the most common application of geopolymerization, a range of refractory and structural products have been produced. The products of geopolymerization are called poly-silicates.
*Galvinized wire? Galvinized wire reinforcing would be light and could probably provide extra resistance to earthquakes. The prices are similar to rebar per pound, but there is perhaps 5 times the support per pound of material. Does not need double thickness, which cuts down on labor.

===Aesthetics===
* [http://www.midwestearthbuilders.com/photogallery.html MEB photo gallery]
* [http://cebtex.com/?page_id=6 CebTex]
* [http://cebtex.com/?page_id=7 CebTex2]


* [http://www.adobemachine.com/midland_project_construction_pic.htm Midland Project Construction Pictures by Earthblock Texas Homes]

Stick frame construction is the main building method in North America. It is a weak but fast building method, which makes money for developers but returns little value to the homeowner, if one considers lifecycle cost of buildings. (note the lifecycle use of materials in Greenforms at CMPBS) Procuring lumber drains money out of local economies. This is not to mention clear-cutting and vast lumber monocultures that supply the lumber. We are interested in raising the standard of building, away from stick frame. We believe that with all these considerations, the CEB is the only building technique that even remotely has a chance of substituting for stick frame construction, and that with our machine, priced $3-5k and designed for fabrication replication, will fill in a great need. CEB construction has the potential for mainstreamability in home construction.

===Soil Composition===
(Unverified Method, Citation)
"A simple soil composition test can be done with a clear jar and some water. Fill the jar half way with soil, then add water to the top. Add a few spoon fulls of salt to help with the separation. Shake the jar vigorously, and then set it down and allow the contents to settle for an hour or two. Once the contents have settled, you will see specific layers form. The bottom layer will be your aggregate, then your clay/silt layer, and finally the organic material will be on top. You want about 15-40% clay/silt to 60-85% sand. Little to no organic matter is best." <ref> http://velacreations.com/component/k2/49-ceb.html </ref>

==Advantages of CEBs==
===Thermal properties===
CEBs are excellent thermal insulators. In very cold climates, a superinsulated building can be made by putting a layer of insulation between two layers of CEBs - see [[Superinsulated CEB Construction]]

Furthermore, they lose and gain heat less quickly than surrounding air. As a result of this, they store warmth in cold weather, and coolness in hot weather.

===Comparison to other natural building methods===
If you want to build a home from natural materials, you have a choice of -
*Wood: stick-frame, timber frame, post and beam
*Structural masonry: brick, concrete block, rock, CEB (note that CEB falls into the class of structural masonry)
*Earth-mix: adobe, rammed earth, stabilized earth blocks, cob, earthbag
*Other natural building methods: strawbale, cordwood, papercrete, [[Earthship|earthships]] and variations of all types.

Earthbag and cordwood construction, though cheap, take too much time. It takes about $400 and 400 man-hours to build the walls and roof of a 200 square foot (18.6m<sup>2</sup>) room. Earthbag construction requires filling, stacking and tamping bags of earth. As the walls get higher, the bags must be lifted accordingly. Barbed wire is strung between layers of bags. The process is not easily mechanized. And the walls require stuccoing afterwards. Cordwood was also difficult. Wood has to be cut, stacked, restacked and stacked again. We were surprised at how much wood was required for a small addition. Furthermore, both cordwood and earthbags have the distinct disadvantage of being irregular. By contrast, CEB construction takes much less time. This is because the blocks made are uniform, whereas other natural building methods use irregular materials.

Wayne Nelson of ''Habitat for Humanity'' in his piece entitled [http://www.networkearth.org/naturalbuilding/ceb.html "Compressed Earth Blocks"] says, "Uniformly sized building components can result in less waste, faster construction and the possibility of using other pre-made components or modular manufactured building elements." High uniformity gives CEB a competitive advantage over other natural building methods, allowing the CEB to influence local economies as a building medium.

===Local production===
Compressed earth blocks exemplify the quality "locally-made". The required clay-sand subsoil is locally available nearly everywhere. Even the mortar is made from this mix with additional water. (See: [http://en.wikipedia.org/wiki/Compressed_earth_block Wikipedia]) Humus-rich top-soil can be preserved for agriculture and the resulting hole may become a basement, root-cellar, pond or smoothed out to blend with the landscape. If onsite soil is insufficient (ie. not enough, or unbalanced) near-by off-site soil or amendments might be an appropriate option. Miles traveled: near Zero.

Compare this to the stick-frame house. According to "Gate-to-Gate Life-Cycle Inventory of Softwood Lumber Production" by Michael R. Milota, Cynthia D. West, and Ian D. Hartley, lumber travels 65 miles on average, just to get to the mill. Numerous unnatural materials are often used (ie vinyl siding and insulation) that have their own set of negative ecological consequences.

Other natural building methods have variably high scores on local, ecological use of materials, provided the materials are locally abundant.

A CEB press can also enhance the local economy through a brickworks facility. Bricks can be made competitively at a local scale. In "Compressed Earth Block Volume 1: Manual of Production" by CRA Terre, Vincent Rigassi ([http://80.237.211.43/basin/publications/index.asp?A=1 see D.10)], CEB is pronounced as "one of those rare 'modern materials' which has sufficient production flexibility to enable it to be integrated into both formal and informal sectors of activity, from 'cottage' industry to full-scale industrial plants" (pg 5).

The third opportunity for local production is to manufacture CEB presses. Our open-source CEB machine ''[[CEB Press|The Liberator]]'' is designed to be built with simple tools and off-the-shelf parts. There is an opportunity for huge profits here as other CEB presses are expensive ($25k for one of 3-5 brick/minute performance). The Liberator's design has minimum welds, using only bolts to secure the frame together. Since no specialized tools or advanced skills are needed, a local machine shop or adventurous entrepreneur can easily manufacture it, contributing to the local economy.

===Durability===

====Strength====

Strength of CEBs depends on the machine (especially automated versus manual) and the quality of the soil (poorly mixed soil can lead to a weaker brick). According to Wikipedia, "CEB can have a compressive strength as high as 2,000 pounds per square inch. Blocks with compressive strengths of 1,200 to 1,400 p.s.i. are common." We have not yet strength-tested blocks from ''The Liberator''.

The compressive strength of CEB sounds impressive, but according to Fred Webster, Ph.D. seismic Engineer in his paper [http://www.deatech.com/natural/cobinfo/adobe.html "Some Thoughts on'Adobe Codes'], it is neither the only nor the most important variable in determining the ability of CEB's to withstand loads. "In actuality, high compressive strength is and should not be the greatest concern related to pressed block quality. If the block has a compressive strength of 1000 psi rather than 300 psi, it is quite superfluous to the performance of the building subjected to ordinary service loads or even earthquake loads. It is not requisite that earthen blocks be up to the standard of concrete in order to perform well during severe earthquake shaking." Webster suggests that soil quality may be more important than compressive strength in determining the bricks overall durability. "Standards for appropriate soil selection need to be aggressively and rationally developed and tested by the pressed block industry. Currently, the best standards and research are being performed by [http://80.237.211.43/basin/basin/index.asp?A=1 BASIN], a combined appropriate technology effort made up of Germany, England, Switzerland, and France" (Webster).

====Water Resistance====

Although high quality blocks are water-resistant, they are not fully waterproof and commercial builders, such as [http://www.midwestearthbuilders.com/ Midwest Earth Builders] use a stucco to protect the exterior walls. Other design features, such as a large overhang, can also provide some protection against weathering.

CEB buildings may need to be re-finished with stucco coating, just like a house would occasionally need new paint. If a conventional roof is used, maintenance repairs would be identical to a traditional house. More research is needed on maintenance costs of a CEB building.

=====Additives to Increase Water Resistance=====

Chemicals called pozzolans have been used for centuries to cause a hydraulic cementing reaction with hydrated lime (CaOH, calcium hydroxide) in damp or wet conditions.

The Romans used volcanic ash with lime and sand to yield a concrete still unrivaled by modern technology.

More common pozzolans may include brick dust (fired below 900*C) and fly ash from power stations.

In theory, the addition of pozzolans such as brick dust to a dry mix of sand, clay, and hydrated lime could yield CEBs that could be used in wet or damp conditions such as retaining walls.

I propose that these CEBs would require a curing period, following pressing, under plastic to encourage hydraulic cement reaction of lime and pozzolan.

[http://repository.upenn.edu/cgi/viewcontent.cgi?article=1178&context=hp_theses Evaluation and Testing of Brick Dust as a Pozzolanic Additive to Lime Mortar for Architectural Conservation]

====Fire and Mold-proof====

===Economics: The press, initial building cost, maintenance===
We have found that earthbag and cordwood costs about $30 per square foot ($322 per square meter) where labour is valued at $10/ hour. CEB construction should be about 5 times cheaper than that; data to follow.

The main cost is the machine for making the CEBs. Commercial versions that make 3-5 blocks a minute cost $25k. This is one reason why we have built [[CEB Press Intro|The Liberator]], an open-source CEB machine that costs $3-5k and can make 9 blocks a minute.

A tractor with loader and rototiller are required to prepare the soil. These are additional costs. Other equipment and their related costs are detailed in the pdf CEB manual [http://80.237.211.43/basin/publications/index.asp?A=1 D.10] found on the BASIN website.

====Building Costs====
[http://www.midwestearthbuilders.com/BuildingInfo.html MEB] claims, "[c]ost on a per block basis average approximately $1.10 per block. A 1000 square foot home will need approximately 5,500 blocks. So, $6,050 would be the block costs. Once again, we have worked with customers who have provided their own labor and tractor for loading, and have brought this cost down to $.50 to $.60/block."

CEB press maker [http://pages.sbcglobal.net/fwehman/AECTOverview.html AECT] claims, "the cost of the structural compressed earth block construction using the AECT structural compressed earth block machines to produce the structural masonry blocks is between 25-40% less expensive than the next closest construction approach for quality, long lasting and energy efficient structures. Some other cheaper construction techniques are inexpensive, but the resulting housing or commercial buildings are cheap, structurally deficient, noisy, and wasteful in energy use and not appealing to homeowners or commercial tenants."

But when compared strictly on economic terms to a conventional home, natural building methods save surprisingly little. Most natural building methods use convential roofs and foundations. Only the walls are constructed from alternative materials.

From their experience, [http://www.midwestearthbuilders.com/BuildingInfo.html Midwest Earth Builders (MEB)] claim "Because CEBs are used entirely as a wall system, the remaining costs, which can represent 80-90% of the total cost of the home, will be the same as conventional building. For example, the cost of the roof, windows, cabinets, etc. are the same for a framed and CEB home.

Building the wall of a home typically represents 10-20% of the total cost of a home. A CEB wall will average 15% more then a conventionally built wall. In other words if the wall of a conventional home cost $15,000 for a $100,000 home, it will cost $2,250 more for a CEB wall."

A similar summary of straw bale housing is given from [http://www.greenhomebuilding.com/strawbale.htm Green Home Building]. "Erecting bale walls can go amazingly quickly, and does not take a lot of skill, but then the rest of the creation of the building is similar to any other wood framed house. In fact strawbale houses typically only save about 15% of the wood used in a conventionally framed house. The cost of finishing a strawbale house can often exceed that of standard construction, because of the specialized work that goes into plastering both sides of the walls. The result is often worth it though, because of the superior insulation and wall depth that is achieved."

A commerical, pre-built 200 sq ft [http://www.philssheds.com/sheds.htm#Deluxe "deluxe shed"] costs $4,400. Missouri minimum wage is $6.50, but if we gave the workers a nice $10/hour, the price is equivalent. ([http://www.postwoodworking.com/shed_pricing.asp Another company] quoted their shed at $4,009 and I found a two-year old aluminum one on craigslist for $1500, which was originally bought at $2500.)

Other points to consider:
#Skill level. Stuccoing straw bale buildings ''may'' be better left to a professional. CEB requires little skill and is therefore, a good choice for the owner-builder. Normal masonary work requires skilled professionals to apply a thick (1/4-1/2") layer of mortar between layers of bricks, but "because earth blocks do not require thick mortar joints, walls can be built quickly by workers unskilled in masonry" [http://www.midwestearthbuilders.com/BuildingInfo.html (MEB)]. [http://www.midwestearthbuilders.com/AboutUs.html MEB] explains, "One does not have to be an experienced mason to build with CEBs. Homeowners, contractors, and builders can quickly be taught how to stack a wall and begin construction immediately. Because only a thin mortar/slurry joint is used between blocks, walls go up quickly and there is no need to wait for the mortar to set up after a few rows like with typical brick masonry."
#Can other parts of the building be made more economically? CEB can be made into roofing shingles with a roof-tile mold [Link?] . Conventional roofs are easily held by CEB: "If the block has a compressive strength of 1000 psi rather than 300 psi, it is quite superfluous to the performance of the building subjected to ordinary service loads or even earthquake loads" [http://www.deatech.com/natural/cobinfo/adobe.html (Webster)]. Thus, it seems safe to assume that a CEB wall, appropriately constructed, could hold up the weight of a living roof. Although again, with current technologies, it is more expensive up-front, with long-term savings in maintenance and heating.
#Because CEB is an on-site material and because all parts of the process can be done by hand or machine, it lends itself to great variability of final product prices. [http://www.networkearth.org/naturalbuilding/ceb.html Habitat for Humanity] uses CEB in some of their projects. And [http://80.237.211.43/basin/partner/index.asp?A=1 BASIN] is comprised of organizations which do development work. So, obviously, CEB homes do NOT need to cost as much as conventionally-built ones.

==Disadvantages of CEBs==
The CEB does fall short of perfection in a couple respects. The press and other needed equipment (ie. rototiller and tractor) are not made from locally harvested materials. However, almost all building methods require use of some heavy machinery, and to its advantage, the press is designed to be locally manufactured. Also, ''The Liberator'' is not designed to make roofing shingles (although these can be made from compressed earth). So, the ecological qualities of the roof cannot be addressed.
Soil composition may not be appropriate on some sites as well which would mean appropriate soil would need top be transported from elswhere [http://www.adobemachine.com/peb/thebiglie.htm (source)].
A potential untested method to perform a basic soil test is described here- http://velacreations.com/shelter/building-materials/dirt/49.html

==More Information==
* [[CEB Press]] - Full information on our high-performance, low-cost, open-source CEB machine: The Liberator.
* [[:Category:The Liberator Full Product Release|The Liberator Full Product Release]]
* [[Earthquake safety]]
* [http://www.institutotierraycal.org/CompressedEarthBlocks.html CEB FAQ] from [[Instituto Tierra y Cal]]
* [http://unesdoc.unesco.org/images/0012/001282/128236e.pdf 100-page CEB handbook] from a Unesco project in Sudan
* [http://www.earthblockinc.com/overview.htm Overview of CEBs], by Jim Hallock
* [http://www.tijol-eco.com.br/infos.html What should we have in mind when acquiring a CEB press?] - CEB legal issues and norms in Brazil
* [[appropedia: Compressed earth brick press]]
* [http://www.earth-auroville.com/index.php?nav=menu&pg=auram&id1=7&lang_code=en Auram earth construction equipment and blocks] from [[Auroville Earth Institute]] (available in many shapes).
* [http://autonopedia.org/buildings_and_shelter/Rammed_Earth.html Rammed Earth Construction] from Autonopedia
* [http://www.whygreenbuildings.com/ecolodgical/page.php?pageID=131 Rammed/Stabilized Earth] from Green Building Encyclopedia
* [http://pages.sbcglobal.net/fwehman/ Advanced Earthen Construction Technologies]
* [http://www.adobemachine.com/ Powell and Sons CEB machines]
* Gernot Minke - one of the world's leaders in earth construction - see [http://www.eartharchitecture.org/index.php?/archives/786-Gernot-Minke.html here] for thorough overview, including detailed soil testing procedures.
* Galvanized wire reinforced, earthquake resistant earth construction techniques publication - [http://sheltercentre.org/sites/default/files/GalvanisedWireReinforcement.pdf]
* Ronald Rael is an Architect, Author and Assistant Professor of Architecture at The University of California, Berkeley. He is the founder of [http://www.eartharchitecture.org EarthArchitecture.org], a clearinghouse of information on the subject.
* Compressed Earth Block Guide - [http://nzdl.sadl.uleth.ca/cgi-bin/library?e=d-00000-00---off-0cdl--00-0--0-10-0---0---0prompt-10---4-------0-1l--11-en-50---20-about---00-0-1-00-0-0-11-1-0utfZz-8-00&a=d&c=cdl&cl=CL2.3&d=HASH01979938ef89e979ddfb736b.9.2]
* GTZ manuals on CEB technology: [http://craterre.org/terre.grenoble.archi.fr/documentation/downloads/CEBVol1.pdf Volume I, Manual of Production] and [http://craterre.org/terre.grenoble.archi.fr/documentation/downloads/CEBVol2.pdf Volume II, Manual of Design and Construction]
* Other information - [http://www.grisb.org/publications/pub34.htm] , [http://www.earthblockinc.com/faq.htm]
* [http://propagelleprojects.blogspot.com/2012/10/compressed-earth-block-ceb-soil.html propagelle project]
* [https://www.researchgate.net/publication/323771402_Compressed_and_Stabilized_Earth_Blocks_in_Louisiana CEB for wet/hurricane climates (Louisiana USA)]

==References==
<references/>
[[Category: CEB]]

Induction Furnace/Research Development

2018-10-14T20:27:32Z

ChuckH: /* Resources */

{{GVCS Header}}

==Overview==
Research in creating the [[Induction Furnace]] with the goal of creating a design that fully complies with [[OSE Spec]].

*[[Induction Furnace Overview]]
* [http://blog.opensourceecology.org/category/global-village-construction-set/induction-furnace/ Induction Furnace blog posts]
*[http://www.basaisteels.com/smbif.html induction furnace steel process]

=Research=

==Design==
[[Image:Induction concept.jpg|right|400px|Induction Furnace Concept]]

* IGBT-based induction furnace power supply - [http://4hv.org/e107_files/public/1250792596_1614_FT74664_design_igbt_lcl.pdf]
* [[:Category: Induction Furnace]]
* [http://blog.opensourceecology.org/forum/induction-furnace/ Induction Furnace Forum]
* [[Induction Furnace Request for Bids]]
* [http://openpario.mime.oregonstate.edu/projects/osif Open Pario]

===Resources===
* [http://www.articlesfactory.com/articles/hobbies/induction-furnace-and-cupola-furnace-information.html Articlesfactory: Furnace Selection]
* [http://inductionheater.org/ Inductionheater.org]
* [http://www.dansworkshop.com/electricity-and-electronics/induction-heating.htm Dansworkshop: Induction Heating]
* [http://www.educypedia.be/electronics/electricityinduction.htm Educypedia: Induction-related Articles]
* [[Appropedia: Induction Heating]]
* [http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat7.html] Home made induction heater
* [http://www.allaboutcircuits.com/ Allaboutcircuits: Articles on Electricity and Electronics]
* [http://www.freepatentsonline.com/3798344.html 1974 US Patent 3798344] Channel Type Induction Furnace (Many induction furnace patents are more than 20 years old, and therefore public domain.)
* [http://www.foundrymag.com/ Foundry Magazine] trade rag
* [http://www.foseco.com/en-gb/end-markets/foundry/reference-centre/download-service/foundry-practice/ Foundry Practice] vendor house rag
* [http://www.inductiontech.com/ Furnace rebuilder]
* [http://www.electric-history.com/~zero/374-HistoryAjax.html Jim Metcalf memoir] Fascinating memoir of a person deeply involved with induction heating development
* [https://www.chaski.org/homemachinist/viewtopic.php?f=24&t=105394 Ajax 50kW induction heater rebuild project]

===DIY Furnaces===
*Simple circuit melts a nail - [https://www.youtube.com/watch?v=pVYMLnXW9uo]
*Power Labs - [http://www.power-labs.com/forum/forum.php]
*http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat1.html
*'''10 kW heater + inverter circuit - [http://www.mindchallenger.com/inductionheater/]'''
*http://www.richieburnett.co.uk/indheat.html
*http://www.hvguy.4hv.org/ih/
*http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat1.html
* '''[http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat9.html Achieved 10 kW]; Induction Furnace Kit: http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat8.html'''
*http://www.dansworkshop.com/electricity-and-electronics/induction-heating.htm
* [http://www.fluxeon.com/Roy1200open.html Roy 1200] is an open source induction heater. Fluxeon sell a [http://elitelam.dot5hosting.com/store/page3.html kit versions] between $196.50 and $326.31 depending on whether all parts are included.

===Commercial===
*Across International - NJ, USA - induction heaters - [http://www.acrossinternational.com/High-Frequency_c84.htm]
*Ajax Magnethermic/Tocco [http://www.ajaxtocco.com/default.asp?ID=391]
*India supplier of induction furnaces - [http://www.auoto-controls.com/induction_heating.htm]
*Commercial induction furnace power supplies from Superior Induction - [http://www.superiorinduction.com/?gclid=CO2fgNqPtZkCFRAhDQodqjeo5Q]
*EPRI works with induction - The EPRI Center for Materials Production at Carnegie Mellon, Pittsburgh, PA, 412-268-3243
* [http://www.made-in-china.com/productdirectory.do?subaction=hunt&mode=and&style=b&isOpenCorrection=1&word=induction+furnace&comProvince=nolimit&code=QimLEmnJSxJQ List of chinese induction furnace manufacturers]
* 110kw 3.1kHz melts 110kg in 1hr. Video[http://www.youtube.com/watch?feature=player_detailpage&v=XnUJMmcId9s]

===Forums===
* [http://blog.opensourceecology.org/forum/induction-furnace/ Open Source Induction Furnace Forum]
* [http://www.cnczone.com/forums/showthread.php?t=13545 CNC Zone - Induction furnace topic]
* [http://www.metalcastingzone.com/metal-casting-forum/casting-furnaces Metal Casting Zone - Furnace Info]
* [http://www.eng-tips.com/threadminder.cfm?pid=330&page=1 Metal and Metallurgy engineering Forum]
* [http://forum.allaboutcircuits.com/ Electronics and electricity]
* [http://www.electro-tech-online.com/ Electronics]

=Links=
*Technical basics and applications of induction furnaces - excellent PDF - [http://www.auoto-controls.com/induction_heating.htm]

==See Also==
* [[Induction Furnace Request for Bids]]
* [http://en.wikipedia.org/wiki/Induction_furnace Wikipedia: Induction Furnace]
* [http://opencapitalist.org/content/detailed-open-source-project-creation Open Source Project Creation]

{{GVCS Footer}}

Induction Furnace/Research Development

2018-10-14T20:24:27Z

ChuckH: /* Resources */

{{GVCS Header}}

==Overview==
Research in creating the [[Induction Furnace]] with the goal of creating a design that fully complies with [[OSE Spec]].

*[[Induction Furnace Overview]]
* [http://blog.opensourceecology.org/category/global-village-construction-set/induction-furnace/ Induction Furnace blog posts]
*[http://www.basaisteels.com/smbif.html induction furnace steel process]

=Research=

==Design==
[[Image:Induction concept.jpg|right|400px|Induction Furnace Concept]]

* IGBT-based induction furnace power supply - [http://4hv.org/e107_files/public/1250792596_1614_FT74664_design_igbt_lcl.pdf]
* [[:Category: Induction Furnace]]
* [http://blog.opensourceecology.org/forum/induction-furnace/ Induction Furnace Forum]
* [[Induction Furnace Request for Bids]]
* [http://openpario.mime.oregonstate.edu/projects/osif Open Pario]

===Resources===
* [http://www.articlesfactory.com/articles/hobbies/induction-furnace-and-cupola-furnace-information.html Articlesfactory: Furnace Selection]
* [http://inductionheater.org/ Inductionheater.org]
* [http://www.dansworkshop.com/electricity-and-electronics/induction-heating.htm Dansworkshop: Induction Heating]
* [http://www.educypedia.be/electronics/electricityinduction.htm Educypedia: Induction-related Articles]
* [[Appropedia: Induction Heating]]
* [http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat7.html] Home made induction heater
* [http://www.allaboutcircuits.com/ Allaboutcircuits: Articles on Electricity and Electronics]
* [http://www.freepatentsonline.com/3798344.html 1974 US Patent 3798344] Channel Type Induction Furnace (Many induction furnace patents are more than 20 years old, and therefore public domain.)
* [http://www.foundrymag.com/ Foundry Magazine] trade rag
* [http://www.foseco.com/en-gb/end-markets/foundry/reference-centre/download-service/foundry-practice/ Foundry Practice] vendor house rag
* [http://www.inductiontech.com/ Furnace rebuilder]
* [http://www.electric-history.com/~zero/374-HistoryAjax.html Jim Metcalf memoir] Fascinating memoir of a person deeply involved with induction heating development

===DIY Furnaces===
*Simple circuit melts a nail - [https://www.youtube.com/watch?v=pVYMLnXW9uo]
*Power Labs - [http://www.power-labs.com/forum/forum.php]
*http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat1.html
*'''10 kW heater + inverter circuit - [http://www.mindchallenger.com/inductionheater/]'''
*http://www.richieburnett.co.uk/indheat.html
*http://www.hvguy.4hv.org/ih/
*http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat1.html
* '''[http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat9.html Achieved 10 kW]; Induction Furnace Kit: http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat8.html'''
*http://www.dansworkshop.com/electricity-and-electronics/induction-heating.htm
* [http://www.fluxeon.com/Roy1200open.html Roy 1200] is an open source induction heater. Fluxeon sell a [http://elitelam.dot5hosting.com/store/page3.html kit versions] between $196.50 and $326.31 depending on whether all parts are included.

===Commercial===
*Across International - NJ, USA - induction heaters - [http://www.acrossinternational.com/High-Frequency_c84.htm]
*Ajax Magnethermic/Tocco [http://www.ajaxtocco.com/default.asp?ID=391]
*India supplier of induction furnaces - [http://www.auoto-controls.com/induction_heating.htm]
*Commercial induction furnace power supplies from Superior Induction - [http://www.superiorinduction.com/?gclid=CO2fgNqPtZkCFRAhDQodqjeo5Q]
*EPRI works with induction - The EPRI Center for Materials Production at Carnegie Mellon, Pittsburgh, PA, 412-268-3243
* [http://www.made-in-china.com/productdirectory.do?subaction=hunt&mode=and&style=b&isOpenCorrection=1&word=induction+furnace&comProvince=nolimit&code=QimLEmnJSxJQ List of chinese induction furnace manufacturers]
* 110kw 3.1kHz melts 110kg in 1hr. Video[http://www.youtube.com/watch?feature=player_detailpage&v=XnUJMmcId9s]

===Forums===
* [http://blog.opensourceecology.org/forum/induction-furnace/ Open Source Induction Furnace Forum]
* [http://www.cnczone.com/forums/showthread.php?t=13545 CNC Zone - Induction furnace topic]
* [http://www.metalcastingzone.com/metal-casting-forum/casting-furnaces Metal Casting Zone - Furnace Info]
* [http://www.eng-tips.com/threadminder.cfm?pid=330&page=1 Metal and Metallurgy engineering Forum]
* [http://forum.allaboutcircuits.com/ Electronics and electricity]
* [http://www.electro-tech-online.com/ Electronics]

=Links=
*Technical basics and applications of induction furnaces - excellent PDF - [http://www.auoto-controls.com/induction_heating.htm]

==See Also==
* [[Induction Furnace Request for Bids]]
* [http://en.wikipedia.org/wiki/Induction_furnace Wikipedia: Induction Furnace]
* [http://opencapitalist.org/content/detailed-open-source-project-creation Open Source Project Creation]

{{GVCS Footer}}

Induction Furnace/Research Development

2018-10-14T19:53:34Z

ChuckH: /* Commercial */

{{GVCS Header}}

==Overview==
Research in creating the [[Induction Furnace]] with the goal of creating a design that fully complies with [[OSE Spec]].

*[[Induction Furnace Overview]]
* [http://blog.opensourceecology.org/category/global-village-construction-set/induction-furnace/ Induction Furnace blog posts]
*[http://www.basaisteels.com/smbif.html induction furnace steel process]

=Research=

==Design==
[[Image:Induction concept.jpg|right|400px|Induction Furnace Concept]]

* IGBT-based induction furnace power supply - [http://4hv.org/e107_files/public/1250792596_1614_FT74664_design_igbt_lcl.pdf]
* [[:Category: Induction Furnace]]
* [http://blog.opensourceecology.org/forum/induction-furnace/ Induction Furnace Forum]
* [[Induction Furnace Request for Bids]]
* [http://openpario.mime.oregonstate.edu/projects/osif Open Pario]

===Resources===
* [http://www.articlesfactory.com/articles/hobbies/induction-furnace-and-cupola-furnace-information.html Articlesfactory: Furnace Selection]
* [http://inductionheater.org/ Inductionheater.org]
* [http://www.dansworkshop.com/electricity-and-electronics/induction-heating.htm Dansworkshop: Induction Heating]
* [http://www.educypedia.be/electronics/electricityinduction.htm Educypedia: Induction-related Articles]
* [[Appropedia: Induction Heating]]
* [http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat7.html] Home made induction heater
* [http://www.allaboutcircuits.com/ Allaboutcircuits: Articles on Electricity and Electronics]
* [http://www.freepatentsonline.com/3798344.html 1974 US Patent 3798344] Channel Type Induction Furnace (Many induction furnace patents are more than 20 years old, and therefore public domain.)
* [http://www.foundrymag.com/ Foundry Magazine] trade rag
* [http://www.foseco.com/en-gb/end-markets/foundry/reference-centre/download-service/foundry-practice/ Foundry Practice] vendor house rag
* [http://www.inductiontech.com/ Furnace rebuilder]
===DIY Furnaces===
*Simple circuit melts a nail - [https://www.youtube.com/watch?v=pVYMLnXW9uo]
*Power Labs - [http://www.power-labs.com/forum/forum.php]
*http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat1.html
*'''10 kW heater + inverter circuit - [http://www.mindchallenger.com/inductionheater/]'''
*http://www.richieburnett.co.uk/indheat.html
*http://www.hvguy.4hv.org/ih/
*http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat1.html
* '''[http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat9.html Achieved 10 kW]; Induction Furnace Kit: http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat8.html'''
*http://www.dansworkshop.com/electricity-and-electronics/induction-heating.htm
* [http://www.fluxeon.com/Roy1200open.html Roy 1200] is an open source induction heater. Fluxeon sell a [http://elitelam.dot5hosting.com/store/page3.html kit versions] between $196.50 and $326.31 depending on whether all parts are included.

===Commercial===
*Across International - NJ, USA - induction heaters - [http://www.acrossinternational.com/High-Frequency_c84.htm]
*Ajax Magnethermic/Tocco [http://www.ajaxtocco.com/default.asp?ID=391]
*India supplier of induction furnaces - [http://www.auoto-controls.com/induction_heating.htm]
*Commercial induction furnace power supplies from Superior Induction - [http://www.superiorinduction.com/?gclid=CO2fgNqPtZkCFRAhDQodqjeo5Q]
*EPRI works with induction - The EPRI Center for Materials Production at Carnegie Mellon, Pittsburgh, PA, 412-268-3243
* [http://www.made-in-china.com/productdirectory.do?subaction=hunt&mode=and&style=b&isOpenCorrection=1&word=induction+furnace&comProvince=nolimit&code=QimLEmnJSxJQ List of chinese induction furnace manufacturers]
* 110kw 3.1kHz melts 110kg in 1hr. Video[http://www.youtube.com/watch?feature=player_detailpage&v=XnUJMmcId9s]

===Forums===
* [http://blog.opensourceecology.org/forum/induction-furnace/ Open Source Induction Furnace Forum]
* [http://www.cnczone.com/forums/showthread.php?t=13545 CNC Zone - Induction furnace topic]
* [http://www.metalcastingzone.com/metal-casting-forum/casting-furnaces Metal Casting Zone - Furnace Info]
* [http://www.eng-tips.com/threadminder.cfm?pid=330&page=1 Metal and Metallurgy engineering Forum]
* [http://forum.allaboutcircuits.com/ Electronics and electricity]
* [http://www.electro-tech-online.com/ Electronics]

=Links=
*Technical basics and applications of induction furnaces - excellent PDF - [http://www.auoto-controls.com/induction_heating.htm]

==See Also==
* [[Induction Furnace Request for Bids]]
* [http://en.wikipedia.org/wiki/Induction_furnace Wikipedia: Induction Furnace]
* [http://opencapitalist.org/content/detailed-open-source-project-creation Open Source Project Creation]

{{GVCS Footer}}

Induction Furnace/Research Development

2018-10-14T19:53:03Z

ChuckH: /* Commercial */ add Atlas magnethermic Tocco link

{{GVCS Header}}

==Overview==
Research in creating the [[Induction Furnace]] with the goal of creating a design that fully complies with [[OSE Spec]].

*[[Induction Furnace Overview]]
* [http://blog.opensourceecology.org/category/global-village-construction-set/induction-furnace/ Induction Furnace blog posts]
*[http://www.basaisteels.com/smbif.html induction furnace steel process]

=Research=

==Design==
[[Image:Induction concept.jpg|right|400px|Induction Furnace Concept]]

* IGBT-based induction furnace power supply - [http://4hv.org/e107_files/public/1250792596_1614_FT74664_design_igbt_lcl.pdf]
* [[:Category: Induction Furnace]]
* [http://blog.opensourceecology.org/forum/induction-furnace/ Induction Furnace Forum]
* [[Induction Furnace Request for Bids]]
* [http://openpario.mime.oregonstate.edu/projects/osif Open Pario]

===Resources===
* [http://www.articlesfactory.com/articles/hobbies/induction-furnace-and-cupola-furnace-information.html Articlesfactory: Furnace Selection]
* [http://inductionheater.org/ Inductionheater.org]
* [http://www.dansworkshop.com/electricity-and-electronics/induction-heating.htm Dansworkshop: Induction Heating]
* [http://www.educypedia.be/electronics/electricityinduction.htm Educypedia: Induction-related Articles]
* [[Appropedia: Induction Heating]]
* [http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat7.html] Home made induction heater
* [http://www.allaboutcircuits.com/ Allaboutcircuits: Articles on Electricity and Electronics]
* [http://www.freepatentsonline.com/3798344.html 1974 US Patent 3798344] Channel Type Induction Furnace (Many induction furnace patents are more than 20 years old, and therefore public domain.)
* [http://www.foundrymag.com/ Foundry Magazine] trade rag
* [http://www.foseco.com/en-gb/end-markets/foundry/reference-centre/download-service/foundry-practice/ Foundry Practice] vendor house rag
* [http://www.inductiontech.com/ Furnace rebuilder]
===DIY Furnaces===
*Simple circuit melts a nail - [https://www.youtube.com/watch?v=pVYMLnXW9uo]
*Power Labs - [http://www.power-labs.com/forum/forum.php]
*http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat1.html
*'''10 kW heater + inverter circuit - [http://www.mindchallenger.com/inductionheater/]'''
*http://www.richieburnett.co.uk/indheat.html
*http://www.hvguy.4hv.org/ih/
*http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat1.html
* '''[http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat9.html Achieved 10 kW]; Induction Furnace Kit: http://webpages.charter.net/dawill/tmoranwms/Elec_IndHeat8.html'''
*http://www.dansworkshop.com/electricity-and-electronics/induction-heating.htm
* [http://www.fluxeon.com/Roy1200open.html Roy 1200] is an open source induction heater. Fluxeon sell a [http://elitelam.dot5hosting.com/store/page3.html kit versions] between $196.50 and $326.31 depending on whether all parts are included.

===Commercial===
*Across International - NJ, USA - induction heaters - [http://www.acrossinternational.com/High-Frequency_c84.htm]
*Atlas Magnethermic/Tocco [http://www.ajaxtocco.com/default.asp?ID=391]
*India supplier of induction furnaces - [http://www.auoto-controls.com/induction_heating.htm]
*Commercial induction furnace power supplies from Superior Induction - [http://www.superiorinduction.com/?gclid=CO2fgNqPtZkCFRAhDQodqjeo5Q]
*EPRI works with induction - The EPRI Center for Materials Production at Carnegie Mellon, Pittsburgh, PA, 412-268-3243
* [http://www.made-in-china.com/productdirectory.do?subaction=hunt&mode=and&style=b&isOpenCorrection=1&word=induction+furnace&comProvince=nolimit&code=QimLEmnJSxJQ List of chinese induction furnace manufacturers]
* 110kw 3.1kHz melts 110kg in 1hr. Video[http://www.youtube.com/watch?feature=player_detailpage&v=XnUJMmcId9s]

===Forums===
* [http://blog.opensourceecology.org/forum/induction-furnace/ Open Source Induction Furnace Forum]
* [http://www.cnczone.com/forums/showthread.php?t=13545 CNC Zone - Induction furnace topic]
* [http://www.metalcastingzone.com/metal-casting-forum/casting-furnaces Metal Casting Zone - Furnace Info]
* [http://www.eng-tips.com/threadminder.cfm?pid=330&page=1 Metal and Metallurgy engineering Forum]
* [http://forum.allaboutcircuits.com/ Electronics and electricity]
* [http://www.electro-tech-online.com/ Electronics]

=Links=
*Technical basics and applications of induction furnaces - excellent PDF - [http://www.auoto-controls.com/induction_heating.htm]

==See Also==
* [[Induction Furnace Request for Bids]]
* [http://en.wikipedia.org/wiki/Induction_furnace Wikipedia: Induction Furnace]
* [http://opencapitalist.org/content/detailed-open-source-project-creation Open Source Project Creation]

{{GVCS Footer}}

Metal Refining

2018-09-04T05:13:36Z

ChuckH: /* Low-Temperature Electrolysis */

==Electrolysis vs. carbothermal reduction (from John Freudenthal)==
In regards to economics, there are two broad methods of metal
refining: electrolysis and carbothermal. Carbothermal is the current
method used for iron, but it works for almost any common metal above a
certain temperature threshold.

'''FeO + CO <=> Fe + CO2'''

For iron, the equilibrium favors the right side of the above equation
above about 800°C [L'vov]. In the case of aluminum, the full reduction
from Al2O3 has two potential reactions.

'''Al2O3 + 3C <=> 2Al + 3CO'''

'''Al2O3 + 3CH4 <=> 2Al + 3CO + 4H2'''

The first reaction has a favored equilibrium on the right starting at
about 2000°C and the latter at about 1500°C [Halman]. In the case of
aluminum, only the electrolysis method (Hall Heroult) is currently
used.

In my opinion, thermodynamics favors large scale production due to the
high temperatures involved. In order to make small scale refinement
feasible, two factors are vital; lower temperature and broad
applicability. Carbothermal reduction has the advantage that it's
broadly applicable. Almost any metal will undergo carbothermal reduction
at some temperature, and the use of methane as a feed material almost
always lowers the necessary temperature a bit to boot.

So if maintaining temperatures above 1500°C seems feasible, then
carbothermal reduction might be the best route, but here is where
feedstock and ore come in to cause trouble. Every rock just insists on
being composed of a disgusting mess of minerals, and pure ores are the
only economical source of pure metals. So if using local feedstock is
a necessity, then finding ''universal purification methods'' is a must.
This is where hydrofluoric acid comes to the rescue. HF will oxidize
(well, here the colloquial term might be 'flouridize') anything.
Fluorides are, in general, more water soluble than oxides (17.2 g/Kl
for AlF3 and zilcho for Al2O3) and most importantly, are volatile and
will evaporate. This allows for simple distillation purification
[Landis], but in this case, low temperature distillation is likely
unfeasible, and hence solution phase separation would be preferable.
Once the AlF3 is isolated, it can be electrolyzed with the Hall
Heroult process (or any electrolysis method) to form pure Al.

In the Landis paper, all separations are done as low temperature
distillations (~100°C) and reductions are done as plasma reductions,
which are obviously not possible here.

The trouble is that flourine is the mother of all oxidizers, and upon
electrolysis it's freed from its AlF3 cage and unleashed upon the world
in its full glory. The flourine will oxidize anything; the anode, the
chamber, the salt bath, people. In Hall Heroult, the feedstock is
generally Al2O3 and a carbon anode is oxidized to CO2, but in the case
of AlF3 feedstock, the reaction generates free flourine, which either
oxidizes the anode to CF4 or likely hydrogen would be added to the
cell to regenerate the HF which then would be pumped out the of the
cell. (Don't quote me on that, I'm having trouble finding the HF bond
strength at 2000°C, but I think it's favored over CF4). The trouble is
that the HF still has to be handled extremely carefully or it will
simply fluorinate anything it touches.

In a broad sense, what I'm proposing instead is to simply reduce
whatever mix of metals you have access to into an alloy, in this case
AlSi and then separate the metallic alloys using a second melt
electrolysis. Its not really any lower energy, and in the end, both
methods still require a high temperature melting. In the case I
propose for Al2(SiO3)3, the second melting step and electrolysis is
relatively easy because the two metals have drastically different
melting points and electrode potentials. In addition, it's all done
with electrolysis and this single cell could be used for both steps if
it was built to withstand 2000°C which would require a good deal of
forethought.

So overall, no economically viable method exists to reduce a mixed
oxide ore to its constituent separated metals. That is what makes this
proposition so much fun.

'''Papers cited:'''

[[File:halman.pdf]]: ''"Carbothermal reduction of alumina: Thermochemical equilibrium calculations and experimental investigation"''

[[File:landis.pdf]]: ''"Materials reﬁning on the Moon"''

[[File:lvov.pdf]]: ''"Mechanism of carbothermal reduction of iron, cobalt, nickel and copper oxides"''

==Small scale solar carbothermal reduction==
Carbothermal reduction reactor for iron reduction, built for future Mars mission by company named [http://www.orbitec.com/ ORBITEC]. The key here is that CSP is focused on soil (ore) in a methane atmosphere, accomplishing the carbothermal reduction. The other steps (methane reforming via catalyst... catch water... electrolysis unit to make oxygen etc.,) would not be necessary on earth and would unnecessarily complicate the idea for our purposes. '''Their''' goal is to release oxygen from the martian soil, our goal is to reduce iron. On earth, it would be simpler to burn the CO for additional heat. Or perhaps more H2 could be generated from CO via [http://en.wikipedia.org/wiki/Water_gas#Lowe.27s_gas_process Lowe's Process] and then fed back into the carbothermal reduction).

<html>
<iframe title="YouTube video player" class="youtube-player" type="text/html" width="480" height="390" src="https://www.youtube.com/embed//P5aNIeYJgbU" frameborder="0" allowFullScreen></iframe>
<iframe title="YouTube video player" class="youtube-player" type="text/html" width="640" height="390" src="https://www.youtube.com/embed//etvuC_htwDE" frameborder="0" allowFullScreen></iframe>
</html>

relevant abstract:
Energy Volume 18, Issue 3, March 1993, Pages 239-249
Copyright © 1993 Published by Elsevier Science Ltd.
==== High-temperature solar thermochemistry: Production of iron and synthesis gas by Fe3O4-reduction with methane ====
A. Steinfeld, P. Kuhn and J. Karni
Paul Scherrer Institute, CH-5232, Villigen-PSI, Switzerland
Weizmann Institute of Science, Rehovot 76100, Israel
Received 18 September 1992. Available online 11 August 2003.
Abstract
Criteria for selecting thermochemical processes that use concentrated solar radiation as the energy source of high-temperature process heat are reviewed. We have thermodynamically examined the system Fe3O4 + 4CH4. At 1 atm and temperatures above 1300 K, the chemical equilibrium components consist of metallic iron in the solid phase and a mixture of 66.7% H2 and 33.3% CO in the gaseous phase. The total energy required to effect this highly endothermic transformation is about 1000 kJ/per mole of Fe3O4 reduced. We conducted exploratory experimental studies in a solar furnace using a solar receiver (with internal infrared mirrors) containing a fluidized bed reactor. Directly irradiated iron oxide particles, fluidized in methane, acted simultaneously as radiant absorbers and chemical reactants, while freshly produced iron particles acted as reaction catalysts. The proposed process offers simultaneous production of iron from its ores and of syngas from natural gas, without discharging CO2 and other pollutants to the environment.

==Comments==
* (Rasmus:) A ''vertical'' system could be designed for solar carbothermal reduction (I can provide a drawing if needed). The pure iron powder would be loaded into a hopper at the top. Through a funnel it falls into a chamber with flame (waste methane, CO, H2), pre-heating the iron powder. From there it falls into funnel, then into a methane-filled chamber where the reduction to metallic iron takes place. This requires temperatures of 800°C or higher, which could be achieved with solar concentrators focused here. At the bottom is a refractory (of the induction furnace), catching the metallic iron, for subsequent casting. The risk of this design is that it may simply '''explode''', if too much oxygen gets into the methane chamber. In an alternative design, the methane could be pre-heated with solar concentrators and then piped into the aforementioned column. Any of these designs are fairly rough on the hardware but may be worth checking out. Heat from burning can be regenerated to pre-heat new methane.
* (Rasmus:) I gather from these two items (video, abstract) that iron reduction under methane using a solar concentrator should be done as a two-step process. The first one would take place at around ca. 800°C to first achieve complete iron reduction. When nearly all of the oxide has been reduced to metallic iron, the solar concentrator can switch into ''melting mode'', i.e. providing much higher temperatures at or above 1350°C.
* (Rasmus:) an idea - it may be possible to melt the iron powder into specific shapes. Formwork made of refractory material would be needed. The advantage is that the new iron object would not have to be cast, which has certain advantages. It would still be hot enough so that it could be hand-forged on an anvil. In general I have my doubts about the stability of such products though.

==Vacuum Distillation==
This appears to be one way to avoid undesired byproducts, such as carbides:

'''''Solar Aluminum Production by Vacuum Carbothermal Reduction of Alumina—Thermodynamic and Experimental Analyses''''' - METALLURGICAL AND MATERIALS TRANSACTIONS B - DOI: 10.1007/s11663-010-9461-6 (found [http://www.springerlink.com/content/73j0h6vn27653w03/ here]) - M. Kruesi, M. E. Galvez, M. Halmann and A. Steinfeld
'''Abstract''' Thermochemical equilibrium calculations indicate the possibility of significantly lowering the onset temperature of aluminum vapor formation via carbothermal reduction of Al2O3 by decreasing the total pressure, enabling its vacuum distillation while bypassing the formation of undesired by-products Al2O, Al4C3, and Al-oxycarbides. Furthermore, the use of concentrated solar energy as the source of high-temperature process heat offers considerable energy savings and reduced concomitant CO2 emissions. When the reducing agent is derived from a biomass source, the solar-driven carbothermal reduction is CO2 neutral. Exploratory experimental runs using a solar reactor were carried out at temperatures in the range 1300 K to 2000 K (1027 °C to 1727 °C) and with total pressures in the range 3.5 to 12 millibar, with reactants Al2O3 and biocharcoal directly exposed to simulated high-flux solar irradiation, yielding up to 19 pct Al by the condensation of product gases, accompanied by the formation of Al4C3 and Al4O4C within the crucible. Based on the measured CO generation, integrated over the duration of the experimental run, the reaction extent reached 55 pct at 2000 K (1727 °C).

== Electrolysis ==

=== Conventional High Temperature Electrolysis ===
[http://en.wikipedia.org/wiki/Hall-H%C3%A9roult_process Hall-Heroult process]

=== Low-Temperature Electrolysis ===

US DOE project: [https://www.osti.gov/servlets/purl/926179]

Poster paper: [[File:Zhang_Reddy_Poster-03-12-05.pdf]], related [https://www.researchgate.net/profile/Venkat_Kamavaram3/publication/279901773_Aluminum_electrowinning_in_ionic_liquids_at_low_temperature/links/59d3d7ceaca2721f436ce17c/Aluminum-electrowinning-in-ionic-liquids-at-low-temperature.pdf article][[Image:Zhang_Reddy.png|thumb|Zhang-Reddy process]]

Low-temperature electrolytic refining ''(speculative)'': Conventional aluminum refining is a lot like electroplating; but water can't be used as an electrolyte and high temperature molten salts are used instead. Recently low-temperature aluminum electroplating has been demonstrated ([http://www.ionmet.eu/fileadmin/ionmet/training/20090324_Munich/2_Ryder_Al.pdf Ionmet], [http://www.jproeng.com/qikan/manage/wenzhang/208139.pdf Yue et al]) using "ionic liquids". These electroplating solutions contain AlCl<sub>3</sub>, which can be extracted from clay as AlCl<sub>3</sub>*6H<sub>2</sub>O by hydrochloric acid leaching; the HCl can possibly be regenerated from the chlorine gas evolved in electrolysis. Several metal oxides are also soluble in recently-developed Deep Eutectic Solvents ([http://en.wikipedia.org/wiki/Deep_eutectic_solvent DES]), which might be the basis of electrolytic refining. [[Image:Oxides.png]] [http://www.rsc.org/Education/EiC/issues/2005_Jan/salty.asp source article here]

==WikiLinks==
[[Direct Reduced Iron (DRI)]], [[Metal]], [[Metal Refining]], [[Induction furnace]], [[Foundry]], [[Metal Evaporation]], [[Kiln]], [[Biomining]], [[Heliostat]],

==External Links==
* [http://www.jfe-21st-cf.or.jp/index2.html Introduction to Iron and Steel Processing] Online Book
* insert

[[Category:Metalworks]]
[[Category:Materials]]
[[Category:Energy]]
[[Category:Solar Power]]

Metal Refining

2018-09-04T05:09:58Z

ChuckH: /* Low-Temperature Electrolysis */

==Electrolysis vs. carbothermal reduction (from John Freudenthal)==
In regards to economics, there are two broad methods of metal
refining: electrolysis and carbothermal. Carbothermal is the current
method used for iron, but it works for almost any common metal above a
certain temperature threshold.

'''FeO + CO <=> Fe + CO2'''

For iron, the equilibrium favors the right side of the above equation
above about 800°C [L'vov]. In the case of aluminum, the full reduction
from Al2O3 has two potential reactions.

'''Al2O3 + 3C <=> 2Al + 3CO'''

'''Al2O3 + 3CH4 <=> 2Al + 3CO + 4H2'''

The first reaction has a favored equilibrium on the right starting at
about 2000°C and the latter at about 1500°C [Halman]. In the case of
aluminum, only the electrolysis method (Hall Heroult) is currently
used.

In my opinion, thermodynamics favors large scale production due to the
high temperatures involved. In order to make small scale refinement
feasible, two factors are vital; lower temperature and broad
applicability. Carbothermal reduction has the advantage that it's
broadly applicable. Almost any metal will undergo carbothermal reduction
at some temperature, and the use of methane as a feed material almost
always lowers the necessary temperature a bit to boot.

So if maintaining temperatures above 1500°C seems feasible, then
carbothermal reduction might be the best route, but here is where
feedstock and ore come in to cause trouble. Every rock just insists on
being composed of a disgusting mess of minerals, and pure ores are the
only economical source of pure metals. So if using local feedstock is
a necessity, then finding ''universal purification methods'' is a must.
This is where hydrofluoric acid comes to the rescue. HF will oxidize
(well, here the colloquial term might be 'flouridize') anything.
Fluorides are, in general, more water soluble than oxides (17.2 g/Kl
for AlF3 and zilcho for Al2O3) and most importantly, are volatile and
will evaporate. This allows for simple distillation purification
[Landis], but in this case, low temperature distillation is likely
unfeasible, and hence solution phase separation would be preferable.
Once the AlF3 is isolated, it can be electrolyzed with the Hall
Heroult process (or any electrolysis method) to form pure Al.

In the Landis paper, all separations are done as low temperature
distillations (~100°C) and reductions are done as plasma reductions,
which are obviously not possible here.

The trouble is that flourine is the mother of all oxidizers, and upon
electrolysis it's freed from its AlF3 cage and unleashed upon the world
in its full glory. The flourine will oxidize anything; the anode, the
chamber, the salt bath, people. In Hall Heroult, the feedstock is
generally Al2O3 and a carbon anode is oxidized to CO2, but in the case
of AlF3 feedstock, the reaction generates free flourine, which either
oxidizes the anode to CF4 or likely hydrogen would be added to the
cell to regenerate the HF which then would be pumped out the of the
cell. (Don't quote me on that, I'm having trouble finding the HF bond
strength at 2000°C, but I think it's favored over CF4). The trouble is
that the HF still has to be handled extremely carefully or it will
simply fluorinate anything it touches.

In a broad sense, what I'm proposing instead is to simply reduce
whatever mix of metals you have access to into an alloy, in this case
AlSi and then separate the metallic alloys using a second melt
electrolysis. Its not really any lower energy, and in the end, both
methods still require a high temperature melting. In the case I
propose for Al2(SiO3)3, the second melting step and electrolysis is
relatively easy because the two metals have drastically different
melting points and electrode potentials. In addition, it's all done
with electrolysis and this single cell could be used for both steps if
it was built to withstand 2000°C which would require a good deal of
forethought.

So overall, no economically viable method exists to reduce a mixed
oxide ore to its constituent separated metals. That is what makes this
proposition so much fun.

'''Papers cited:'''

[[File:halman.pdf]]: ''"Carbothermal reduction of alumina: Thermochemical equilibrium calculations and experimental investigation"''

[[File:landis.pdf]]: ''"Materials reﬁning on the Moon"''

[[File:lvov.pdf]]: ''"Mechanism of carbothermal reduction of iron, cobalt, nickel and copper oxides"''

==Small scale solar carbothermal reduction==
Carbothermal reduction reactor for iron reduction, built for future Mars mission by company named [http://www.orbitec.com/ ORBITEC]. The key here is that CSP is focused on soil (ore) in a methane atmosphere, accomplishing the carbothermal reduction. The other steps (methane reforming via catalyst... catch water... electrolysis unit to make oxygen etc.,) would not be necessary on earth and would unnecessarily complicate the idea for our purposes. '''Their''' goal is to release oxygen from the martian soil, our goal is to reduce iron. On earth, it would be simpler to burn the CO for additional heat. Or perhaps more H2 could be generated from CO via [http://en.wikipedia.org/wiki/Water_gas#Lowe.27s_gas_process Lowe's Process] and then fed back into the carbothermal reduction).

<html>
<iframe title="YouTube video player" class="youtube-player" type="text/html" width="480" height="390" src="https://www.youtube.com/embed//P5aNIeYJgbU" frameborder="0" allowFullScreen></iframe>
<iframe title="YouTube video player" class="youtube-player" type="text/html" width="640" height="390" src="https://www.youtube.com/embed//etvuC_htwDE" frameborder="0" allowFullScreen></iframe>
</html>

relevant abstract:
Energy Volume 18, Issue 3, March 1993, Pages 239-249
Copyright © 1993 Published by Elsevier Science Ltd.
==== High-temperature solar thermochemistry: Production of iron and synthesis gas by Fe3O4-reduction with methane ====
A. Steinfeld, P. Kuhn and J. Karni
Paul Scherrer Institute, CH-5232, Villigen-PSI, Switzerland
Weizmann Institute of Science, Rehovot 76100, Israel
Received 18 September 1992. Available online 11 August 2003.
Abstract
Criteria for selecting thermochemical processes that use concentrated solar radiation as the energy source of high-temperature process heat are reviewed. We have thermodynamically examined the system Fe3O4 + 4CH4. At 1 atm and temperatures above 1300 K, the chemical equilibrium components consist of metallic iron in the solid phase and a mixture of 66.7% H2 and 33.3% CO in the gaseous phase. The total energy required to effect this highly endothermic transformation is about 1000 kJ/per mole of Fe3O4 reduced. We conducted exploratory experimental studies in a solar furnace using a solar receiver (with internal infrared mirrors) containing a fluidized bed reactor. Directly irradiated iron oxide particles, fluidized in methane, acted simultaneously as radiant absorbers and chemical reactants, while freshly produced iron particles acted as reaction catalysts. The proposed process offers simultaneous production of iron from its ores and of syngas from natural gas, without discharging CO2 and other pollutants to the environment.

==Comments==
* (Rasmus:) A ''vertical'' system could be designed for solar carbothermal reduction (I can provide a drawing if needed). The pure iron powder would be loaded into a hopper at the top. Through a funnel it falls into a chamber with flame (waste methane, CO, H2), pre-heating the iron powder. From there it falls into funnel, then into a methane-filled chamber where the reduction to metallic iron takes place. This requires temperatures of 800°C or higher, which could be achieved with solar concentrators focused here. At the bottom is a refractory (of the induction furnace), catching the metallic iron, for subsequent casting. The risk of this design is that it may simply '''explode''', if too much oxygen gets into the methane chamber. In an alternative design, the methane could be pre-heated with solar concentrators and then piped into the aforementioned column. Any of these designs are fairly rough on the hardware but may be worth checking out. Heat from burning can be regenerated to pre-heat new methane.
* (Rasmus:) I gather from these two items (video, abstract) that iron reduction under methane using a solar concentrator should be done as a two-step process. The first one would take place at around ca. 800°C to first achieve complete iron reduction. When nearly all of the oxide has been reduced to metallic iron, the solar concentrator can switch into ''melting mode'', i.e. providing much higher temperatures at or above 1350°C.
* (Rasmus:) an idea - it may be possible to melt the iron powder into specific shapes. Formwork made of refractory material would be needed. The advantage is that the new iron object would not have to be cast, which has certain advantages. It would still be hot enough so that it could be hand-forged on an anvil. In general I have my doubts about the stability of such products though.

==Vacuum Distillation==
This appears to be one way to avoid undesired byproducts, such as carbides:

'''''Solar Aluminum Production by Vacuum Carbothermal Reduction of Alumina—Thermodynamic and Experimental Analyses''''' - METALLURGICAL AND MATERIALS TRANSACTIONS B - DOI: 10.1007/s11663-010-9461-6 (found [http://www.springerlink.com/content/73j0h6vn27653w03/ here]) - M. Kruesi, M. E. Galvez, M. Halmann and A. Steinfeld
'''Abstract''' Thermochemical equilibrium calculations indicate the possibility of significantly lowering the onset temperature of aluminum vapor formation via carbothermal reduction of Al2O3 by decreasing the total pressure, enabling its vacuum distillation while bypassing the formation of undesired by-products Al2O, Al4C3, and Al-oxycarbides. Furthermore, the use of concentrated solar energy as the source of high-temperature process heat offers considerable energy savings and reduced concomitant CO2 emissions. When the reducing agent is derived from a biomass source, the solar-driven carbothermal reduction is CO2 neutral. Exploratory experimental runs using a solar reactor were carried out at temperatures in the range 1300 K to 2000 K (1027 °C to 1727 °C) and with total pressures in the range 3.5 to 12 millibar, with reactants Al2O3 and biocharcoal directly exposed to simulated high-flux solar irradiation, yielding up to 19 pct Al by the condensation of product gases, accompanied by the formation of Al4C3 and Al4O4C within the crucible. Based on the measured CO generation, integrated over the duration of the experimental run, the reaction extent reached 55 pct at 2000 K (1727 °C).

== Electrolysis ==

=== Conventional High Temperature Electrolysis ===
[http://en.wikipedia.org/wiki/Hall-H%C3%A9roult_process Hall-Heroult process]

=== Low-Temperature Electrolysis ===

US DOE project: [http://www1.eere.energy.gov/industry/aluminum/pdfs/ionicliquids.pdf]

Poster paper: [[File:Zhang_Reddy_Poster-03-12-05.pdf]], related [https://www.researchgate.net/profile/Venkat_Kamavaram3/publication/279901773_Aluminum_electrowinning_in_ionic_liquids_at_low_temperature/links/59d3d7ceaca2721f436ce17c/Aluminum-electrowinning-in-ionic-liquids-at-low-temperature.pdf article][[Image:Zhang_Reddy.png|thumb|Zhang-Reddy process]]

Low-temperature electrolytic refining ''(speculative)'': Conventional aluminum refining is a lot like electroplating; but water can't be used as an electrolyte and high temperature molten salts are used instead. Recently low-temperature aluminum electroplating has been demonstrated ([http://www.ionmet.eu/fileadmin/ionmet/training/20090324_Munich/2_Ryder_Al.pdf Ionmet], [http://www.jproeng.com/qikan/manage/wenzhang/208139.pdf Yue et al]) using "ionic liquids". These electroplating solutions contain AlCl<sub>3</sub>, which can be extracted from clay as AlCl<sub>3</sub>*6H<sub>2</sub>O by hydrochloric acid leaching; the HCl can possibly be regenerated from the chlorine gas evolved in electrolysis. Several metal oxides are also soluble in recently-developed Deep Eutectic Solvents ([http://en.wikipedia.org/wiki/Deep_eutectic_solvent DES]), which might be the basis of electrolytic refining. [[Image:Oxides.png]] [http://www.rsc.org/Education/EiC/issues/2005_Jan/salty.asp source article here]

==WikiLinks==
[[Direct Reduced Iron (DRI)]], [[Metal]], [[Metal Refining]], [[Induction furnace]], [[Foundry]], [[Metal Evaporation]], [[Kiln]], [[Biomining]], [[Heliostat]],

==External Links==
* [http://www.jfe-21st-cf.or.jp/index2.html Introduction to Iron and Steel Processing] Online Book
* insert

[[Category:Metalworks]]
[[Category:Materials]]
[[Category:Energy]]
[[Category:Solar Power]]

Induction Furnace Overview

2018-09-04T04:23:09Z

ChuckH: /* Yoke */

{{Template:Category=Induction furnace}}
==Overview==
{{Induction Furnace}}

==Introduction==

The Open Source Induction Furnace Project seems to be the most promising way to implement the [[foundry]].
This project involves the design of:
* a high-power induction furnace circuit (between 20 and 50 kW), and
* the melting chamber proper

==test==
Well, we could buy a turnkey system perhaps for $5k total used, and run it from the LifeTrac generator. The only disadvantage to this route is that if it breaks we’re dead-in-the-water – either with the impossibility of fixing closed-source technology, or a high repair bill. A single component which blows and is inaccessible for fixing could in principle turn a working power supply into worthless junk. Thus, it is worthwhile to tame this technology by open-sourcing the design.

===Goals===

To fulfill our [[foundry]] goals,
The furnace should have the following characteristics:

#Induction furnace or any other technology that can do this within a budget of 40 kW of electric input, with minimal pollution
#Suitable for melting all metals and alloying
#150 lb per hour steel melting furnace for casting
#240 v ac, 40 kW power source available

(This spec implies ~260watt-hr/lb, which may be optimistic -- see [[Induction_Furnace_Overview#Melt_Calculations |Melt calculations]])

==Conceptual Diagram==

This is a conceptual diagram of the entire Induction Furnace system from the [[Global Village Construction Set]]. The furnace is powered by 20 kW of 240VAC electricity from the [[LifeTrac]] generator. The entire system includes the power electronics, induction coil, and heating vessel - into which metal for melting is inserted. This diagram intends to document the relationship of functional components in the induction furnace system, as a basis for technical development of components and their integration.

The electronics part should be adaptable to different metals and different metal melting coil geometries. Melting coils should also be modular, such that the power electronics can feed different coils. Basic functions include selection of heating frequencies, which are required for melting different metals or metal geometries. There should be a feedback in the electronics, where the amount of power given to the coil should match the quantity/geometry of metal being melted.

[[Image:induction_concept.jpg]]

==Details==
The complete design should include all of the following:

===Induction Furnace Circuit===
# Scalable from 20 up to 50 kW (perhaps even more)in units of 1 or 5 kW
# Allows for power and frequency range selection for different materials and heating devices
## small crucibles ~50kW, ~1kHz
## heat treating small parts ~5kW, ~100kHz
# Incorporates self-tuning to track the coil resonance dynamically during operation
# Power source may be either 1 or 3 phase electrical power
See also [[Induction_Furnace_Overview#Power_Supply |Power Supply Notes]] below.

===Heat Dissipation System===
Specifications of a cooling or heat dissipation system.

===Coil===
# Modular, adaptable design specifications for primary coil windings
Water-cooled copper tubing coil. Compute skin depth at operating frequency in order to estimate useful thickness of copper section.

=== Yoke ===

In lower frequency furnaces, a laminated iron yoke surrounds the coil, forming part of the magnetic circuit, increasing coil power factor, and thus improving efficiency. The yoke also mechanically resists the large radial forces from the coil. See the useful description of the art in [http://www.google.com/patents/US5247539 US Pat. 5247539]

Steel laminations begin to have high losses at the 1kHz frequency level and soft magnetic composites (e.g. iron powder [http://www.hoganas.com/Segments/Somaloy-Technology/Home/ Somaloy]) might be considered. The biggest problem seems to be that the powder needs to be compressed at 20-50 tons/sq in in order to get good magnetic properties. A bit much for the CEB! Also poweder cost is unknown.

I also looked briefly at steel wire for the yoke but [http://www.pmt.usp.br/academic/landgraf/nossos%20artigos%20em%20pdf/03lan%20smm%20mag%20wire.pdf this paper] was not encouraging.

===Resonating Capacitors===
Modular capacitor bank to accommodate different coil inductances and operating frequencies in different applications.

Induction heating capacitors carry high currents and larger sizes are usually water-cooled to deal with their internal heating. Typically polypropylene is the primary dielectric (due to its low loss factor), combined with dielectric oil and sometimes an additional kraft paper layer. Commercial suppliers of capacitors: [[http://www.celem.com/ Celem]] [[http://www.geindustrial.com/publibrary/checkout/Material%20Safety%20Data%20Sheets%7CIHM_design_aid%7CPDF GE]]

If these high-power capacitors are to be made of local materials, the DIY Tesla coil community (e.g. [http://4hv.org/e107_plugins/forum/forum_viewtopic.php?60477], [http://wiki.4hv.org/index.php/Rolled_foil_capacitor_-_60_kV,_3.5_nF]) may have useful experience.
For oil-filled-paper designs, castor oil has a long history in HV pulse applications and canola[http://www.petroferm.com/datasheets/357_TDS.pdf] oil has become commercially accepted for power frequency applications. ([[Vegetable_Oil_Production |Canola oil]] is also a likely candidate for [[Hydraulic_Fluid |hydraulic fluid]].) Oil/paper may have dielectric loss factor ~1% (as opposed to polypropylene ~0.05%) so pay attention to internal heating.

===Melt Chamber===
# Geometical design of melt chamber and basic power transfer calculations
# Should include provisions for loading and pouring
# Given our goals, which is best: a coreless or a channel induction furnace type [http://www.wisegeek.com/what-is-an-induction-furnace.htm] ?
## channel: useful in the melting of lower melt temperature metals; less turbulence at the surface.
## coreless: stronger stirring, simpler crucible construction, most commonly used for induction scrap melting
# Pouring: manual pouring methods are more suited to low volume production lines.
====Crucible====
[[File:FirebrickTemps.png |thumb|Firebrick melting point vs Alumina:Silica composition]]
The crucible is made of refractory ceramic which resists the high temperatures of the melt. Even the best materials erode in use, and crucibles must be replaced on a regular basis. An induction furnace crucible may be either
# separately manufactured, fired in a kiln, and subsequently installed in the furnace, or
# formed in place, and sintered (fired) in the induction furnace itself

'''Materials'''

According to this [http://www.foseco.com/en-gb/end-markets/foundry/foseco-home-uk/ Foseco refractories] brochure[http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf], [[File:Furnace-linings-ferrous-01.pdf]] steel foundry induction-furnace applications typically use alumina or magnesia refractories, while cast-iron foundries use high purity silica. This is related to acid/base chemistry of the melt.

Fireclay (which can be a natural alumina/silica clay) for making refractory crucibles must withstand the superheated molten steel temperature of >3000F. Fireclay [http://www.mineralszone.com/minerals/fire-clay.html] is temperature-rated by Pyrometric Cone Equivalent (PCE) [http://www.ortonceramic.com/resources/reference/cone_ref.shtml]; "High Duty" (>= PCE32) or "Super Duty" (>= PCE35) is needed for ferrous metals. Such fireclay has high alumina content. (See also [[Aluminum_Extractor/Research_Development |Aluminum Extractor]] feedstock.)

Some worthwhile DIY fireclay/firebrick information [http://www.traditionaloven.com/articles/101/what-is-fire-clay-and-where-to-get-it here]

'''Separately made crucible'''
* See: [http://www.engineeredceramics.com/products/crucibles-and-ladle-liners.html Engineered Ceramics Service Guides]
<html><iframe width="320" height="240" src="//www.youtube.com/embed/jEKjLSz1ATw?feature=player_embedded" frameborder="0" allowfullscreen></iframe></html>
* DIY small crucible video [http://www.youtube.com/watch?v=E3my6-nxFjM&feature=player_detailpage]<br>

'''Sintered-in-place crucible'''

The materials described in the [http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf Foseco brocure] cited above are "dry-vibratable", meaning they are powders, rammed into place in situ, and sintered in the furnace itself, rather than being seperately made, kiln-fired crucibles. The refractory is rammed against a hollow steel internal ''former'' which defines the inside surface of the crucible. During the first power application, the former transfers sintering heat to the refractory, then either
* is melted away with the first heat leaving a fully-sintered lining[http://www.atlasfdry.com/inductionfurnaces.htm], or
* gets removed at a lower temperature, allowing re-use[http://www.dhanaprakash.com/product.php?nm=lp1&disc=ladleinductionfur.txt&type=Induction%20Furnace%20Removable%20Former%20Sintering&typeid=19&colorbg=6], with final sintering completed by gas flame before the first melting run

===Other Considerations===
# Complete bill of materials
# Fabrication files for circuit and other components
# Sourcing information for components
# System design and process flow drawings

==Notes==
===Benny===
I just read that you plan to build up an induction furnace. That´s a an interesting and exciting plan.While reading the article some remarks came to my mind.

But before I want to introduce myself:

I am Benny from Germany, Hannover.
I am diploma engineer for electrotechnology and working at the university. I am dealing with some induction heating/ melting applications like induction melting of glasses (that is possible!) and induction furnaces for cast iron.

Some remarks from my point of view:

# It is possible to build up a low cost furnace with the mentioned parameters.
# The frequency of 9,6 kHz is much to high. The efficiancy will be so bad, that it will be hardly possible to melt steel or iron. Due to the small penetration depth of about 2 mm with this frequency and this electrical resistance. So it needs a really small diameter of the crucible, and thats not helpful. Also the refractory material will be strained too much, so that a small lifetime is given. This will raise the cost for the operating.
# 50 Hz or 60 Hz is a better solution. And you can save the cost for the hf-converter.
# How much material do you want to cast at one time? The maximum, what i expect to be possible with 50 kW will be about 50 to 60 kg.
# What kind of raw material should be charged? It is important for the starting, because the initial density should not be too small (packing density). And the other question is, what kind of scrap it will be.
There are so many problems known with content of zinc (hot zinc dipped) and other materials. The lifetime of common refractory material is really small. And what is more important the security for the personal is not given without a strong exhaust system, due to the toxic steam. I expect this as a strong cost factor.

===Power Supply===
There are two approaches to providing the single-phase high-frequency AC power required by the induction furnace coil
* Electronic converter ([[Universal_Power_Supply |Universal Power Supply]])
** Wide frequency tunability possible - including very high frequencies for heat treating small parts
** Dynamic auto-tuning to coil resonance using established phase detector control methods
** power source: DC from [[Battery |battery]] storage banks
** power source: AC from 50/60Hz power
*** Typically the induction furnace power converter then operates AC->DC->AC
*** Preferably 3 phase AC source at higher power levels (better efficiency)
*** 50/60Hz AC can come from battery banks thru DC->AC converter, or from [[Generator |rotary generator]] driven by engine or hydraulic motor

* [[Generator |Rotary generator]]
** Limited frequency range
*** up to ~1kHz with slightly-modified conventional automotive alternator [http://www.venselenterprises.com/techtipsfromdick_files/alternators.pdf][http://www.delcoremy.com/Documents/Electrical-Specifications---Selection-Guide.aspx] (e.g. Delco 30SI 16 pole @ 10000 rpm = 1333Hz), perhaps adequate for crucible melting applications. [http://www.thebackshed.com/windmill/FPRewire.asp Fisher Paykel washing machine motors] are 48- or 56-pole permanent magnet designs often converted to generators and might operate into the low kilohertz range.
*** Commercial induction heating supplies in mid-20th century often used motor-generator sets. Here is a vertical-shaft one rated 50kW 3000 Hz from [https://www.chaski.org/homemachinist/download/file.php?id=59926&mode=view Ajax Magnethermics]
*** >100kHz historically feasible with [http://en.wikipedia.org/wiki/Alexanderson_alternator Alexanderson reluctance generators]
*** frequency controlled by varying shaft speed: frequency = shaft speed * pole pairs
*** dynamic auto-tuning to coil resonance may be difficult
** Three phase vs single phase
*** most reasonably-efficient rotary generators deliver balanced three-phase power, but an induction furnace is a single-phase load
*** this can be addressed with a simple tuned load balancer [http://www.google.com/patents/US3331909], but this may require manual tap- and capacitor adjustments depending on the load
*** alternatively a solid-state static synchronous compensator (STATCOM) can be applied, as described for example in [http://www.strutherstech.com/PDF/STATCOM%20LOAD%20BALANCING.pdf]
*** a combination of the above two methods (carrying most of the load unbalance with fixed capacitors/reactors and using a relatively low-VAR static compensator) might be most economical
** Mechanical power source
*** electric motor (motor-generator set)
*** prime mover (internal combustion or [[Steam_Engine |steam engine]])
*** hydraulic
**** [[Power_Cube |Power Cube]]
**** [[Stationary_Hydraulic_Power |Stationary hydraulic power]]
**** shaft speed control by variable displacement motor or [[Stationary_Hydraulic_Power#Hydraulic_pressure_transformation |hydraulic transformer]]

----
*50 kW for $1600 - [http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200415768835&rvr_id=&crlp=1_263602_263622&UA=L*F%3F&GUID=1357ab741250a0265337bec7ff94d6a7&itemid=200415768835&ff4=263602_263622]
*20 kw STC 3 phase 120 - 480V, also 1 phase - generator - $692 -[http://cgi.ebay.com/20kw-STC-3-Phase-277-480-12-Wire-generator-Head-altern_W0QQitemZ160369799644QQcmdZViewItemQQptZBI_Generators?hash=item2556c8f1dc]
*50 kw STC 3 phase- $1300 - [http://cgi.ebay.com/50KW-STC-3-Phase-12-Wire-generator-alternator_W0QQitemZ160357088416QQcmdZViewItemQQptZBI_Generators?hash=item255606fca0]
**LifeTrac 55 hp can produce 38 kW with this head

===Melt Calculations===
[[Image:inductioncalc.jpg]]

''Note:'' Electrical input requirements may be reduced somewhat by preheating the charge with flame or direct solar energy.

[[Image:imgp4545.jpg|600px]]

Photo I took while visiting a foundry near Santa Fe. Seems relevant!

==Wiki Links==

*[[Foundry]]

*[[Induction Furnace Request for Bids]]

==External Links==
* [http://blog.opensourceecology.org/?p=1373 Original Blog Post]
* [http://web.archive.org/web/20100816034057/http://www.uie.org/webfm_send/391 Technical basics and applications of induction furnace PDF]

==See Also==
{{Induction Furnace}}

[[Category:Induction_Furnace]]

Induction Furnace Overview

2018-09-03T20:39:02Z

ChuckH: /* Power Supply */

{{Template:Category=Induction furnace}}
==Overview==
{{Induction Furnace}}

==Introduction==

The Open Source Induction Furnace Project seems to be the most promising way to implement the [[foundry]].
This project involves the design of:
* a high-power induction furnace circuit (between 20 and 50 kW), and
* the melting chamber proper

==test==
Well, we could buy a turnkey system perhaps for $5k total used, and run it from the LifeTrac generator. The only disadvantage to this route is that if it breaks we’re dead-in-the-water – either with the impossibility of fixing closed-source technology, or a high repair bill. A single component which blows and is inaccessible for fixing could in principle turn a working power supply into worthless junk. Thus, it is worthwhile to tame this technology by open-sourcing the design.

===Goals===

To fulfill our [[foundry]] goals,
The furnace should have the following characteristics:

#Induction furnace or any other technology that can do this within a budget of 40 kW of electric input, with minimal pollution
#Suitable for melting all metals and alloying
#150 lb per hour steel melting furnace for casting
#240 v ac, 40 kW power source available

(This spec implies ~260watt-hr/lb, which may be optimistic -- see [[Induction_Furnace_Overview#Melt_Calculations |Melt calculations]])

==Conceptual Diagram==

This is a conceptual diagram of the entire Induction Furnace system from the [[Global Village Construction Set]]. The furnace is powered by 20 kW of 240VAC electricity from the [[LifeTrac]] generator. The entire system includes the power electronics, induction coil, and heating vessel - into which metal for melting is inserted. This diagram intends to document the relationship of functional components in the induction furnace system, as a basis for technical development of components and their integration.

The electronics part should be adaptable to different metals and different metal melting coil geometries. Melting coils should also be modular, such that the power electronics can feed different coils. Basic functions include selection of heating frequencies, which are required for melting different metals or metal geometries. There should be a feedback in the electronics, where the amount of power given to the coil should match the quantity/geometry of metal being melted.

[[Image:induction_concept.jpg]]

==Details==
The complete design should include all of the following:

===Induction Furnace Circuit===
# Scalable from 20 up to 50 kW (perhaps even more)in units of 1 or 5 kW
# Allows for power and frequency range selection for different materials and heating devices
## small crucibles ~50kW, ~1kHz
## heat treating small parts ~5kW, ~100kHz
# Incorporates self-tuning to track the coil resonance dynamically during operation
# Power source may be either 1 or 3 phase electrical power
See also [[Induction_Furnace_Overview#Power_Supply |Power Supply Notes]] below.

===Heat Dissipation System===
Specifications of a cooling or heat dissipation system.

===Coil===
# Modular, adaptable design specifications for primary coil windings
Water-cooled copper tubing coil. Compute skin depth at operating frequency in order to estimate useful thickness of copper section.

=== Yoke ===

In lower frequency furnaces, it seems a cylindrical iron or steel yoke surrounds the coil, forming part of the magnetic circuit, increasing coil power factor, and thus improving efficiency. This Turkish manufacturer [http://web.archive.org/web/20100205092811/http://www.demora.com.tr/index.php/meltshop/induction-furnace/magnetic-yoke.html] uses 0.3mm (0.012in) thick laminated transformer steel for the yoke. See also the useful description of the art in [http://www.google.com/patents/US5247539 US Pat. 5247539]

Steel laminations begin to have high losses at the 1kHz frequency level and soft magnetic composites (e.g. iron powder [http://www.hoganas.com/Segments/Somaloy-Technology/Home/ Somaloy]) might be considered. The biggest problem seems to be that the powder needs to be compressed at 20-50 tons/sq in in order to get good magnetic properties. A bit much for the CEB! Also poweder cost is unknown.

I also looked briefly at steel wire for the yoke but [http://www.pmt.usp.br/academic/landgraf/nossos%20artigos%20em%20pdf/03lan%20smm%20mag%20wire.pdf this paper] was not encouraging.

===Resonating Capacitors===
Modular capacitor bank to accommodate different coil inductances and operating frequencies in different applications.

Induction heating capacitors carry high currents and larger sizes are usually water-cooled to deal with their internal heating. Typically polypropylene is the primary dielectric (due to its low loss factor), combined with dielectric oil and sometimes an additional kraft paper layer. Commercial suppliers of capacitors: [[http://www.celem.com/ Celem]] [[http://www.geindustrial.com/publibrary/checkout/Material%20Safety%20Data%20Sheets%7CIHM_design_aid%7CPDF GE]]

If these high-power capacitors are to be made of local materials, the DIY Tesla coil community (e.g. [http://4hv.org/e107_plugins/forum/forum_viewtopic.php?60477], [http://wiki.4hv.org/index.php/Rolled_foil_capacitor_-_60_kV,_3.5_nF]) may have useful experience.
For oil-filled-paper designs, castor oil has a long history in HV pulse applications and canola[http://www.petroferm.com/datasheets/357_TDS.pdf] oil has become commercially accepted for power frequency applications. ([[Vegetable_Oil_Production |Canola oil]] is also a likely candidate for [[Hydraulic_Fluid |hydraulic fluid]].) Oil/paper may have dielectric loss factor ~1% (as opposed to polypropylene ~0.05%) so pay attention to internal heating.

===Melt Chamber===
# Geometical design of melt chamber and basic power transfer calculations
# Should include provisions for loading and pouring
# Given our goals, which is best: a coreless or a channel induction furnace type [http://www.wisegeek.com/what-is-an-induction-furnace.htm] ?
## channel: useful in the melting of lower melt temperature metals; less turbulence at the surface.
## coreless: stronger stirring, simpler crucible construction, most commonly used for induction scrap melting
# Pouring: manual pouring methods are more suited to low volume production lines.
====Crucible====
[[File:FirebrickTemps.png |thumb|Firebrick melting point vs Alumina:Silica composition]]
The crucible is made of refractory ceramic which resists the high temperatures of the melt. Even the best materials erode in use, and crucibles must be replaced on a regular basis. An induction furnace crucible may be either
# separately manufactured, fired in a kiln, and subsequently installed in the furnace, or
# formed in place, and sintered (fired) in the induction furnace itself

'''Materials'''

According to this [http://www.foseco.com/en-gb/end-markets/foundry/foseco-home-uk/ Foseco refractories] brochure[http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf], [[File:Furnace-linings-ferrous-01.pdf]] steel foundry induction-furnace applications typically use alumina or magnesia refractories, while cast-iron foundries use high purity silica. This is related to acid/base chemistry of the melt.

Fireclay (which can be a natural alumina/silica clay) for making refractory crucibles must withstand the superheated molten steel temperature of >3000F. Fireclay [http://www.mineralszone.com/minerals/fire-clay.html] is temperature-rated by Pyrometric Cone Equivalent (PCE) [http://www.ortonceramic.com/resources/reference/cone_ref.shtml]; "High Duty" (>= PCE32) or "Super Duty" (>= PCE35) is needed for ferrous metals. Such fireclay has high alumina content. (See also [[Aluminum_Extractor/Research_Development |Aluminum Extractor]] feedstock.)

Some worthwhile DIY fireclay/firebrick information [http://www.traditionaloven.com/articles/101/what-is-fire-clay-and-where-to-get-it here]

'''Separately made crucible'''
* See: [http://www.engineeredceramics.com/products/crucibles-and-ladle-liners.html Engineered Ceramics Service Guides]
<html><iframe width="320" height="240" src="//www.youtube.com/embed/jEKjLSz1ATw?feature=player_embedded" frameborder="0" allowfullscreen></iframe></html>
* DIY small crucible video [http://www.youtube.com/watch?v=E3my6-nxFjM&feature=player_detailpage]<br>

'''Sintered-in-place crucible'''

The materials described in the [http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf Foseco brocure] cited above are "dry-vibratable", meaning they are powders, rammed into place in situ, and sintered in the furnace itself, rather than being seperately made, kiln-fired crucibles. The refractory is rammed against a hollow steel internal ''former'' which defines the inside surface of the crucible. During the first power application, the former transfers sintering heat to the refractory, then either
* is melted away with the first heat leaving a fully-sintered lining[http://www.atlasfdry.com/inductionfurnaces.htm], or
* gets removed at a lower temperature, allowing re-use[http://www.dhanaprakash.com/product.php?nm=lp1&disc=ladleinductionfur.txt&type=Induction%20Furnace%20Removable%20Former%20Sintering&typeid=19&colorbg=6], with final sintering completed by gas flame before the first melting run

===Other Considerations===
# Complete bill of materials
# Fabrication files for circuit and other components
# Sourcing information for components
# System design and process flow drawings

==Notes==
===Benny===
I just read that you plan to build up an induction furnace. That´s a an interesting and exciting plan.While reading the article some remarks came to my mind.

But before I want to introduce myself:

I am Benny from Germany, Hannover.
I am diploma engineer for electrotechnology and working at the university. I am dealing with some induction heating/ melting applications like induction melting of glasses (that is possible!) and induction furnaces for cast iron.

Some remarks from my point of view:

# It is possible to build up a low cost furnace with the mentioned parameters.
# The frequency of 9,6 kHz is much to high. The efficiancy will be so bad, that it will be hardly possible to melt steel or iron. Due to the small penetration depth of about 2 mm with this frequency and this electrical resistance. So it needs a really small diameter of the crucible, and thats not helpful. Also the refractory material will be strained too much, so that a small lifetime is given. This will raise the cost for the operating.
# 50 Hz or 60 Hz is a better solution. And you can save the cost for the hf-converter.
# How much material do you want to cast at one time? The maximum, what i expect to be possible with 50 kW will be about 50 to 60 kg.
# What kind of raw material should be charged? It is important for the starting, because the initial density should not be too small (packing density). And the other question is, what kind of scrap it will be.
There are so many problems known with content of zinc (hot zinc dipped) and other materials. The lifetime of common refractory material is really small. And what is more important the security for the personal is not given without a strong exhaust system, due to the toxic steam. I expect this as a strong cost factor.

===Power Supply===
There are two approaches to providing the single-phase high-frequency AC power required by the induction furnace coil
* Electronic converter ([[Universal_Power_Supply |Universal Power Supply]])
** Wide frequency tunability possible - including very high frequencies for heat treating small parts
** Dynamic auto-tuning to coil resonance using established phase detector control methods
** power source: DC from [[Battery |battery]] storage banks
** power source: AC from 50/60Hz power
*** Typically the induction furnace power converter then operates AC->DC->AC
*** Preferably 3 phase AC source at higher power levels (better efficiency)
*** 50/60Hz AC can come from battery banks thru DC->AC converter, or from [[Generator |rotary generator]] driven by engine or hydraulic motor

* [[Generator |Rotary generator]]
** Limited frequency range
*** up to ~1kHz with slightly-modified conventional automotive alternator [http://www.venselenterprises.com/techtipsfromdick_files/alternators.pdf][http://www.delcoremy.com/Documents/Electrical-Specifications---Selection-Guide.aspx] (e.g. Delco 30SI 16 pole @ 10000 rpm = 1333Hz), perhaps adequate for crucible melting applications. [http://www.thebackshed.com/windmill/FPRewire.asp Fisher Paykel washing machine motors] are 48- or 56-pole permanent magnet designs often converted to generators and might operate into the low kilohertz range.
*** Commercial induction heating supplies in mid-20th century often used motor-generator sets. Here is a vertical-shaft one rated 50kW 3000 Hz from [https://www.chaski.org/homemachinist/download/file.php?id=59926&mode=view Ajax Magnethermics]
*** >100kHz historically feasible with [http://en.wikipedia.org/wiki/Alexanderson_alternator Alexanderson reluctance generators]
*** frequency controlled by varying shaft speed: frequency = shaft speed * pole pairs
*** dynamic auto-tuning to coil resonance may be difficult
** Three phase vs single phase
*** most reasonably-efficient rotary generators deliver balanced three-phase power, but an induction furnace is a single-phase load
*** this can be addressed with a simple tuned load balancer [http://www.google.com/patents/US3331909], but this may require manual tap- and capacitor adjustments depending on the load
*** alternatively a solid-state static synchronous compensator (STATCOM) can be applied, as described for example in [http://www.strutherstech.com/PDF/STATCOM%20LOAD%20BALANCING.pdf]
*** a combination of the above two methods (carrying most of the load unbalance with fixed capacitors/reactors and using a relatively low-VAR static compensator) might be most economical
** Mechanical power source
*** electric motor (motor-generator set)
*** prime mover (internal combustion or [[Steam_Engine |steam engine]])
*** hydraulic
**** [[Power_Cube |Power Cube]]
**** [[Stationary_Hydraulic_Power |Stationary hydraulic power]]
**** shaft speed control by variable displacement motor or [[Stationary_Hydraulic_Power#Hydraulic_pressure_transformation |hydraulic transformer]]

----
*50 kW for $1600 - [http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200415768835&rvr_id=&crlp=1_263602_263622&UA=L*F%3F&GUID=1357ab741250a0265337bec7ff94d6a7&itemid=200415768835&ff4=263602_263622]
*20 kw STC 3 phase 120 - 480V, also 1 phase - generator - $692 -[http://cgi.ebay.com/20kw-STC-3-Phase-277-480-12-Wire-generator-Head-altern_W0QQitemZ160369799644QQcmdZViewItemQQptZBI_Generators?hash=item2556c8f1dc]
*50 kw STC 3 phase- $1300 - [http://cgi.ebay.com/50KW-STC-3-Phase-12-Wire-generator-alternator_W0QQitemZ160357088416QQcmdZViewItemQQptZBI_Generators?hash=item255606fca0]
**LifeTrac 55 hp can produce 38 kW with this head

===Melt Calculations===
[[Image:inductioncalc.jpg]]

''Note:'' Electrical input requirements may be reduced somewhat by preheating the charge with flame or direct solar energy.

[[Image:imgp4545.jpg|600px]]

Photo I took while visiting a foundry near Santa Fe. Seems relevant!

==Wiki Links==

*[[Foundry]]

*[[Induction Furnace Request for Bids]]

==External Links==
* [http://blog.opensourceecology.org/?p=1373 Original Blog Post]
* [http://web.archive.org/web/20100816034057/http://www.uie.org/webfm_send/391 Technical basics and applications of induction furnace PDF]

==See Also==
{{Induction Furnace}}

[[Category:Induction_Furnace]]

Induction Furnace Overview

2018-09-03T20:38:05Z

ChuckH: /* Power Supply */

{{Template:Category=Induction furnace}}
==Overview==
{{Induction Furnace}}

==Introduction==

The Open Source Induction Furnace Project seems to be the most promising way to implement the [[foundry]].
This project involves the design of:
* a high-power induction furnace circuit (between 20 and 50 kW), and
* the melting chamber proper

==test==
Well, we could buy a turnkey system perhaps for $5k total used, and run it from the LifeTrac generator. The only disadvantage to this route is that if it breaks we’re dead-in-the-water – either with the impossibility of fixing closed-source technology, or a high repair bill. A single component which blows and is inaccessible for fixing could in principle turn a working power supply into worthless junk. Thus, it is worthwhile to tame this technology by open-sourcing the design.

===Goals===

To fulfill our [[foundry]] goals,
The furnace should have the following characteristics:

#Induction furnace or any other technology that can do this within a budget of 40 kW of electric input, with minimal pollution
#Suitable for melting all metals and alloying
#150 lb per hour steel melting furnace for casting
#240 v ac, 40 kW power source available

(This spec implies ~260watt-hr/lb, which may be optimistic -- see [[Induction_Furnace_Overview#Melt_Calculations |Melt calculations]])

==Conceptual Diagram==

This is a conceptual diagram of the entire Induction Furnace system from the [[Global Village Construction Set]]. The furnace is powered by 20 kW of 240VAC electricity from the [[LifeTrac]] generator. The entire system includes the power electronics, induction coil, and heating vessel - into which metal for melting is inserted. This diagram intends to document the relationship of functional components in the induction furnace system, as a basis for technical development of components and their integration.

The electronics part should be adaptable to different metals and different metal melting coil geometries. Melting coils should also be modular, such that the power electronics can feed different coils. Basic functions include selection of heating frequencies, which are required for melting different metals or metal geometries. There should be a feedback in the electronics, where the amount of power given to the coil should match the quantity/geometry of metal being melted.

[[Image:induction_concept.jpg]]

==Details==
The complete design should include all of the following:

===Induction Furnace Circuit===
# Scalable from 20 up to 50 kW (perhaps even more)in units of 1 or 5 kW
# Allows for power and frequency range selection for different materials and heating devices
## small crucibles ~50kW, ~1kHz
## heat treating small parts ~5kW, ~100kHz
# Incorporates self-tuning to track the coil resonance dynamically during operation
# Power source may be either 1 or 3 phase electrical power
See also [[Induction_Furnace_Overview#Power_Supply |Power Supply Notes]] below.

===Heat Dissipation System===
Specifications of a cooling or heat dissipation system.

===Coil===
# Modular, adaptable design specifications for primary coil windings
Water-cooled copper tubing coil. Compute skin depth at operating frequency in order to estimate useful thickness of copper section.

=== Yoke ===

In lower frequency furnaces, it seems a cylindrical iron or steel yoke surrounds the coil, forming part of the magnetic circuit, increasing coil power factor, and thus improving efficiency. This Turkish manufacturer [http://web.archive.org/web/20100205092811/http://www.demora.com.tr/index.php/meltshop/induction-furnace/magnetic-yoke.html] uses 0.3mm (0.012in) thick laminated transformer steel for the yoke. See also the useful description of the art in [http://www.google.com/patents/US5247539 US Pat. 5247539]

Steel laminations begin to have high losses at the 1kHz frequency level and soft magnetic composites (e.g. iron powder [http://www.hoganas.com/Segments/Somaloy-Technology/Home/ Somaloy]) might be considered. The biggest problem seems to be that the powder needs to be compressed at 20-50 tons/sq in in order to get good magnetic properties. A bit much for the CEB! Also poweder cost is unknown.

I also looked briefly at steel wire for the yoke but [http://www.pmt.usp.br/academic/landgraf/nossos%20artigos%20em%20pdf/03lan%20smm%20mag%20wire.pdf this paper] was not encouraging.

===Resonating Capacitors===
Modular capacitor bank to accommodate different coil inductances and operating frequencies in different applications.

Induction heating capacitors carry high currents and larger sizes are usually water-cooled to deal with their internal heating. Typically polypropylene is the primary dielectric (due to its low loss factor), combined with dielectric oil and sometimes an additional kraft paper layer. Commercial suppliers of capacitors: [[http://www.celem.com/ Celem]] [[http://www.geindustrial.com/publibrary/checkout/Material%20Safety%20Data%20Sheets%7CIHM_design_aid%7CPDF GE]]

If these high-power capacitors are to be made of local materials, the DIY Tesla coil community (e.g. [http://4hv.org/e107_plugins/forum/forum_viewtopic.php?60477], [http://wiki.4hv.org/index.php/Rolled_foil_capacitor_-_60_kV,_3.5_nF]) may have useful experience.
For oil-filled-paper designs, castor oil has a long history in HV pulse applications and canola[http://www.petroferm.com/datasheets/357_TDS.pdf] oil has become commercially accepted for power frequency applications. ([[Vegetable_Oil_Production |Canola oil]] is also a likely candidate for [[Hydraulic_Fluid |hydraulic fluid]].) Oil/paper may have dielectric loss factor ~1% (as opposed to polypropylene ~0.05%) so pay attention to internal heating.

===Melt Chamber===
# Geometical design of melt chamber and basic power transfer calculations
# Should include provisions for loading and pouring
# Given our goals, which is best: a coreless or a channel induction furnace type [http://www.wisegeek.com/what-is-an-induction-furnace.htm] ?
## channel: useful in the melting of lower melt temperature metals; less turbulence at the surface.
## coreless: stronger stirring, simpler crucible construction, most commonly used for induction scrap melting
# Pouring: manual pouring methods are more suited to low volume production lines.
====Crucible====
[[File:FirebrickTemps.png |thumb|Firebrick melting point vs Alumina:Silica composition]]
The crucible is made of refractory ceramic which resists the high temperatures of the melt. Even the best materials erode in use, and crucibles must be replaced on a regular basis. An induction furnace crucible may be either
# separately manufactured, fired in a kiln, and subsequently installed in the furnace, or
# formed in place, and sintered (fired) in the induction furnace itself

'''Materials'''

According to this [http://www.foseco.com/en-gb/end-markets/foundry/foseco-home-uk/ Foseco refractories] brochure[http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf], [[File:Furnace-linings-ferrous-01.pdf]] steel foundry induction-furnace applications typically use alumina or magnesia refractories, while cast-iron foundries use high purity silica. This is related to acid/base chemistry of the melt.

Fireclay (which can be a natural alumina/silica clay) for making refractory crucibles must withstand the superheated molten steel temperature of >3000F. Fireclay [http://www.mineralszone.com/minerals/fire-clay.html] is temperature-rated by Pyrometric Cone Equivalent (PCE) [http://www.ortonceramic.com/resources/reference/cone_ref.shtml]; "High Duty" (>= PCE32) or "Super Duty" (>= PCE35) is needed for ferrous metals. Such fireclay has high alumina content. (See also [[Aluminum_Extractor/Research_Development |Aluminum Extractor]] feedstock.)

Some worthwhile DIY fireclay/firebrick information [http://www.traditionaloven.com/articles/101/what-is-fire-clay-and-where-to-get-it here]

'''Separately made crucible'''
* See: [http://www.engineeredceramics.com/products/crucibles-and-ladle-liners.html Engineered Ceramics Service Guides]
<html><iframe width="320" height="240" src="//www.youtube.com/embed/jEKjLSz1ATw?feature=player_embedded" frameborder="0" allowfullscreen></iframe></html>
* DIY small crucible video [http://www.youtube.com/watch?v=E3my6-nxFjM&feature=player_detailpage]<br>

'''Sintered-in-place crucible'''

The materials described in the [http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf Foseco brocure] cited above are "dry-vibratable", meaning they are powders, rammed into place in situ, and sintered in the furnace itself, rather than being seperately made, kiln-fired crucibles. The refractory is rammed against a hollow steel internal ''former'' which defines the inside surface of the crucible. During the first power application, the former transfers sintering heat to the refractory, then either
* is melted away with the first heat leaving a fully-sintered lining[http://www.atlasfdry.com/inductionfurnaces.htm], or
* gets removed at a lower temperature, allowing re-use[http://www.dhanaprakash.com/product.php?nm=lp1&disc=ladleinductionfur.txt&type=Induction%20Furnace%20Removable%20Former%20Sintering&typeid=19&colorbg=6], with final sintering completed by gas flame before the first melting run

===Other Considerations===
# Complete bill of materials
# Fabrication files for circuit and other components
# Sourcing information for components
# System design and process flow drawings

==Notes==
===Benny===
I just read that you plan to build up an induction furnace. That´s a an interesting and exciting plan.While reading the article some remarks came to my mind.

But before I want to introduce myself:

I am Benny from Germany, Hannover.
I am diploma engineer for electrotechnology and working at the university. I am dealing with some induction heating/ melting applications like induction melting of glasses (that is possible!) and induction furnaces for cast iron.

Some remarks from my point of view:

# It is possible to build up a low cost furnace with the mentioned parameters.
# The frequency of 9,6 kHz is much to high. The efficiancy will be so bad, that it will be hardly possible to melt steel or iron. Due to the small penetration depth of about 2 mm with this frequency and this electrical resistance. So it needs a really small diameter of the crucible, and thats not helpful. Also the refractory material will be strained too much, so that a small lifetime is given. This will raise the cost for the operating.
# 50 Hz or 60 Hz is a better solution. And you can save the cost for the hf-converter.
# How much material do you want to cast at one time? The maximum, what i expect to be possible with 50 kW will be about 50 to 60 kg.
# What kind of raw material should be charged? It is important for the starting, because the initial density should not be too small (packing density). And the other question is, what kind of scrap it will be.
There are so many problems known with content of zinc (hot zinc dipped) and other materials. The lifetime of common refractory material is really small. And what is more important the security for the personal is not given without a strong exhaust system, due to the toxic steam. I expect this as a strong cost factor.

===Power Supply===
There are two approaches to providing the single-phase high-frequency AC power required by the induction furnace coil
* Electronic converter ([[Universal_Power_Supply |Universal Power Supply]])
** Wide frequency tunability possible - including very high frequencies for heat treating small parts
** Dynamic auto-tuning to coil resonance using established phase detector control methods
** power source: DC from [[Battery |battery]] storage banks
** power source: AC from 50/60Hz power
*** Typically the induction furnace power converter then operates AC->DC->AC
*** Preferably 3 phase AC source at higher power levels (better efficiency)
*** 50/60Hz AC can come from battery banks thru DC->AC converter, or from [[Generator |rotary generator]] driven by engine or hydraulic motor

* [[Generator |Rotary generator]]
** Limited frequency range
*** up to ~1kHz with slightly-modified conventional automotive alternator [http://www.venselenterprises.com/techtipsfromdick_files/alternators.pdf][http://www.delcoremy.com/Documents/Electrical-Specifications---Selection-Guide.aspx] (e.g. Delco 30SI 16 pole @ 10000 rpm = 1333Hz), perhaps adequate for crucible melting applications. [http://www.thebackshed.com/windmill/FPRewire.asp Fisher Paykel washing machine motors] are 48- or 56-pole permanent magnet designs often converted to generators and might operate into the low kilohertz range.
*** Commercial induction heating supplies in mid-20th century often used motor-generator sets. Here is one rated 50kW 3000 Hz from [https://www.chaski.org/homemachinist/download/file.php?id=59926&mode=view Ajax Magnethermics]
*** >100kHz historically feasible with [http://en.wikipedia.org/wiki/Alexanderson_alternator Alexanderson reluctance generators]
*** frequency controlled by varying shaft speed: frequency = shaft speed * pole pairs
*** dynamic auto-tuning to coil resonance may be difficult
** Three phase vs single phase
*** most reasonably-efficient rotary generators deliver balanced three-phase power, but an induction furnace is a single-phase load
*** this can be addressed with a simple tuned load balancer [http://www.google.com/patents/US3331909], but this may require manual tap- and capacitor adjustments depending on the load
*** alternatively a solid-state static synchronous compensator (STATCOM) can be applied, as described for example in [http://www.strutherstech.com/PDF/STATCOM%20LOAD%20BALANCING.pdf]
*** a combination of the above two methods (carrying most of the load unbalance with fixed capacitors/reactors and using a relatively low-VAR static compensator) might be most economical
** Mechanical power source
*** electric motor (motor-generator set)
*** prime mover (internal combustion or [[Steam_Engine |steam engine]])
*** hydraulic
**** [[Power_Cube |Power Cube]]
**** [[Stationary_Hydraulic_Power |Stationary hydraulic power]]
**** shaft speed control by variable displacement motor or [[Stationary_Hydraulic_Power#Hydraulic_pressure_transformation |hydraulic transformer]]

----
*50 kW for $1600 - [http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200415768835&rvr_id=&crlp=1_263602_263622&UA=L*F%3F&GUID=1357ab741250a0265337bec7ff94d6a7&itemid=200415768835&ff4=263602_263622]
*20 kw STC 3 phase 120 - 480V, also 1 phase - generator - $692 -[http://cgi.ebay.com/20kw-STC-3-Phase-277-480-12-Wire-generator-Head-altern_W0QQitemZ160369799644QQcmdZViewItemQQptZBI_Generators?hash=item2556c8f1dc]
*50 kw STC 3 phase- $1300 - [http://cgi.ebay.com/50KW-STC-3-Phase-12-Wire-generator-alternator_W0QQitemZ160357088416QQcmdZViewItemQQptZBI_Generators?hash=item255606fca0]
**LifeTrac 55 hp can produce 38 kW with this head

===Melt Calculations===
[[Image:inductioncalc.jpg]]

''Note:'' Electrical input requirements may be reduced somewhat by preheating the charge with flame or direct solar energy.

[[Image:imgp4545.jpg|600px]]

Photo I took while visiting a foundry near Santa Fe. Seems relevant!

==Wiki Links==

*[[Foundry]]

*[[Induction Furnace Request for Bids]]

==External Links==
* [http://blog.opensourceecology.org/?p=1373 Original Blog Post]
* [http://web.archive.org/web/20100816034057/http://www.uie.org/webfm_send/391 Technical basics and applications of induction furnace PDF]

==See Also==
{{Induction Furnace}}

[[Category:Induction_Furnace]]

Induction Furnace Overview

2018-09-02T18:02:35Z

ChuckH: /* Crucible */

{{Template:Category=Induction furnace}}
==Overview==
{{Induction Furnace}}

==Introduction==

The Open Source Induction Furnace Project seems to be the most promising way to implement the [[foundry]].
This project involves the design of:
* a high-power induction furnace circuit (between 20 and 50 kW), and
* the melting chamber proper

==test==
Well, we could buy a turnkey system perhaps for $5k total used, and run it from the LifeTrac generator. The only disadvantage to this route is that if it breaks we’re dead-in-the-water – either with the impossibility of fixing closed-source technology, or a high repair bill. A single component which blows and is inaccessible for fixing could in principle turn a working power supply into worthless junk. Thus, it is worthwhile to tame this technology by open-sourcing the design.

===Goals===

To fulfill our [[foundry]] goals,
The furnace should have the following characteristics:

#Induction furnace or any other technology that can do this within a budget of 40 kW of electric input, with minimal pollution
#Suitable for melting all metals and alloying
#150 lb per hour steel melting furnace for casting
#240 v ac, 40 kW power source available

(This spec implies ~260watt-hr/lb, which may be optimistic -- see [[Induction_Furnace_Overview#Melt_Calculations |Melt calculations]])

==Conceptual Diagram==

This is a conceptual diagram of the entire Induction Furnace system from the [[Global Village Construction Set]]. The furnace is powered by 20 kW of 240VAC electricity from the [[LifeTrac]] generator. The entire system includes the power electronics, induction coil, and heating vessel - into which metal for melting is inserted. This diagram intends to document the relationship of functional components in the induction furnace system, as a basis for technical development of components and their integration.

The electronics part should be adaptable to different metals and different metal melting coil geometries. Melting coils should also be modular, such that the power electronics can feed different coils. Basic functions include selection of heating frequencies, which are required for melting different metals or metal geometries. There should be a feedback in the electronics, where the amount of power given to the coil should match the quantity/geometry of metal being melted.

[[Image:induction_concept.jpg]]

==Details==
The complete design should include all of the following:

===Induction Furnace Circuit===
# Scalable from 20 up to 50 kW (perhaps even more)in units of 1 or 5 kW
# Allows for power and frequency range selection for different materials and heating devices
## small crucibles ~50kW, ~1kHz
## heat treating small parts ~5kW, ~100kHz
# Incorporates self-tuning to track the coil resonance dynamically during operation
# Power source may be either 1 or 3 phase electrical power
See also [[Induction_Furnace_Overview#Power_Supply |Power Supply Notes]] below.

===Heat Dissipation System===
Specifications of a cooling or heat dissipation system.

===Coil===
# Modular, adaptable design specifications for primary coil windings
Water-cooled copper tubing coil. Compute skin depth at operating frequency in order to estimate useful thickness of copper section.

=== Yoke ===

In lower frequency furnaces, it seems a cylindrical iron or steel yoke surrounds the coil, forming part of the magnetic circuit, increasing coil power factor, and thus improving efficiency. This Turkish manufacturer [http://web.archive.org/web/20100205092811/http://www.demora.com.tr/index.php/meltshop/induction-furnace/magnetic-yoke.html] uses 0.3mm (0.012in) thick laminated transformer steel for the yoke. See also the useful description of the art in [http://www.google.com/patents/US5247539 US Pat. 5247539]

Steel laminations begin to have high losses at the 1kHz frequency level and soft magnetic composites (e.g. iron powder [http://www.hoganas.com/Segments/Somaloy-Technology/Home/ Somaloy]) might be considered. The biggest problem seems to be that the powder needs to be compressed at 20-50 tons/sq in in order to get good magnetic properties. A bit much for the CEB! Also poweder cost is unknown.

I also looked briefly at steel wire for the yoke but [http://www.pmt.usp.br/academic/landgraf/nossos%20artigos%20em%20pdf/03lan%20smm%20mag%20wire.pdf this paper] was not encouraging.

===Resonating Capacitors===
Modular capacitor bank to accommodate different coil inductances and operating frequencies in different applications.

Induction heating capacitors carry high currents and larger sizes are usually water-cooled to deal with their internal heating. Typically polypropylene is the primary dielectric (due to its low loss factor), combined with dielectric oil and sometimes an additional kraft paper layer. Commercial suppliers of capacitors: [[http://www.celem.com/ Celem]] [[http://www.geindustrial.com/publibrary/checkout/Material%20Safety%20Data%20Sheets%7CIHM_design_aid%7CPDF GE]]

If these high-power capacitors are to be made of local materials, the DIY Tesla coil community (e.g. [http://4hv.org/e107_plugins/forum/forum_viewtopic.php?60477], [http://wiki.4hv.org/index.php/Rolled_foil_capacitor_-_60_kV,_3.5_nF]) may have useful experience.
For oil-filled-paper designs, castor oil has a long history in HV pulse applications and canola[http://www.petroferm.com/datasheets/357_TDS.pdf] oil has become commercially accepted for power frequency applications. ([[Vegetable_Oil_Production |Canola oil]] is also a likely candidate for [[Hydraulic_Fluid |hydraulic fluid]].) Oil/paper may have dielectric loss factor ~1% (as opposed to polypropylene ~0.05%) so pay attention to internal heating.

===Melt Chamber===
# Geometical design of melt chamber and basic power transfer calculations
# Should include provisions for loading and pouring
# Given our goals, which is best: a coreless or a channel induction furnace type [http://www.wisegeek.com/what-is-an-induction-furnace.htm] ?
## channel: useful in the melting of lower melt temperature metals; less turbulence at the surface.
## coreless: stronger stirring, simpler crucible construction, most commonly used for induction scrap melting
# Pouring: manual pouring methods are more suited to low volume production lines.
====Crucible====
[[File:FirebrickTemps.png |thumb|Firebrick melting point vs Alumina:Silica composition]]
The crucible is made of refractory ceramic which resists the high temperatures of the melt. Even the best materials erode in use, and crucibles must be replaced on a regular basis. An induction furnace crucible may be either
# separately manufactured, fired in a kiln, and subsequently installed in the furnace, or
# formed in place, and sintered (fired) in the induction furnace itself

'''Materials'''

According to this [http://www.foseco.com/en-gb/end-markets/foundry/foseco-home-uk/ Foseco refractories] brochure[http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf], [[File:Furnace-linings-ferrous-01.pdf]] steel foundry induction-furnace applications typically use alumina or magnesia refractories, while cast-iron foundries use high purity silica. This is related to acid/base chemistry of the melt.

Fireclay (which can be a natural alumina/silica clay) for making refractory crucibles must withstand the superheated molten steel temperature of >3000F. Fireclay [http://www.mineralszone.com/minerals/fire-clay.html] is temperature-rated by Pyrometric Cone Equivalent (PCE) [http://www.ortonceramic.com/resources/reference/cone_ref.shtml]; "High Duty" (>= PCE32) or "Super Duty" (>= PCE35) is needed for ferrous metals. Such fireclay has high alumina content. (See also [[Aluminum_Extractor/Research_Development |Aluminum Extractor]] feedstock.)

Some worthwhile DIY fireclay/firebrick information [http://www.traditionaloven.com/articles/101/what-is-fire-clay-and-where-to-get-it here]

'''Separately made crucible'''
* See: [http://www.engineeredceramics.com/products/crucibles-and-ladle-liners.html Engineered Ceramics Service Guides]
<html><iframe width="320" height="240" src="//www.youtube.com/embed/jEKjLSz1ATw?feature=player_embedded" frameborder="0" allowfullscreen></iframe></html>
* DIY small crucible video [http://www.youtube.com/watch?v=E3my6-nxFjM&feature=player_detailpage]<br>

'''Sintered-in-place crucible'''

The materials described in the [http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf Foseco brocure] cited above are "dry-vibratable", meaning they are powders, rammed into place in situ, and sintered in the furnace itself, rather than being seperately made, kiln-fired crucibles. The refractory is rammed against a hollow steel internal ''former'' which defines the inside surface of the crucible. During the first power application, the former transfers sintering heat to the refractory, then either
* is melted away with the first heat leaving a fully-sintered lining[http://www.atlasfdry.com/inductionfurnaces.htm], or
* gets removed at a lower temperature, allowing re-use[http://www.dhanaprakash.com/product.php?nm=lp1&disc=ladleinductionfur.txt&type=Induction%20Furnace%20Removable%20Former%20Sintering&typeid=19&colorbg=6], with final sintering completed by gas flame before the first melting run

===Other Considerations===
# Complete bill of materials
# Fabrication files for circuit and other components
# Sourcing information for components
# System design and process flow drawings

==Notes==
===Benny===
I just read that you plan to build up an induction furnace. That´s a an interesting and exciting plan.While reading the article some remarks came to my mind.

But before I want to introduce myself:

I am Benny from Germany, Hannover.
I am diploma engineer for electrotechnology and working at the university. I am dealing with some induction heating/ melting applications like induction melting of glasses (that is possible!) and induction furnaces for cast iron.

Some remarks from my point of view:

# It is possible to build up a low cost furnace with the mentioned parameters.
# The frequency of 9,6 kHz is much to high. The efficiancy will be so bad, that it will be hardly possible to melt steel or iron. Due to the small penetration depth of about 2 mm with this frequency and this electrical resistance. So it needs a really small diameter of the crucible, and thats not helpful. Also the refractory material will be strained too much, so that a small lifetime is given. This will raise the cost for the operating.
# 50 Hz or 60 Hz is a better solution. And you can save the cost for the hf-converter.
# How much material do you want to cast at one time? The maximum, what i expect to be possible with 50 kW will be about 50 to 60 kg.
# What kind of raw material should be charged? It is important for the starting, because the initial density should not be too small (packing density). And the other question is, what kind of scrap it will be.
There are so many problems known with content of zinc (hot zinc dipped) and other materials. The lifetime of common refractory material is really small. And what is more important the security for the personal is not given without a strong exhaust system, due to the toxic steam. I expect this as a strong cost factor.

===Power Supply===
There are two approaches to providing the single-phase high-frequency AC power required by the induction furnace coil
* Electronic converter ([[Universal_Power_Supply |Universal Power Supply]])
** Wide frequency tunability possible - including very high frequencies for heat treating small parts
** Dynamic auto-tuning to coil resonance using established phase detector control methods
** power source: DC from [[Battery |battery]] storage banks
** power source: AC from 50/60Hz power
*** Typically the induction furnace power converter then operates AC->DC->AC
*** Preferably 3 phase AC source at higher power levels (better efficiency)
*** 50/60Hz AC can come from battery banks thru DC->AC converter, or from [[Generator |rotary generator]] driven by engine or hydraulic motor

* [[Generator |Rotary generator]]
** Limited frequency range
*** up to ~1kHz with slightly-modified conventional automotive alternator [http://www.venselenterprises.com/techtipsfromdick_files/alternators.pdf][http://www.delcoremy.com/Documents/Electrical-Specifications---Selection-Guide.aspx] (e.g. Delco 30SI 16 pole @ 10000 rpm = 1333Hz), perhaps adequate for crucible melting applications. [http://www.thebackshed.com/windmill/FPRewire.asp Fisher Paykel washing machine motors] are 48- or 56-pole permanent magnet designs often converted to generators and might operate into the low kilohertz range.
*** >100kHz historically feasible with [http://en.wikipedia.org/wiki/Alexanderson_alternator Alexanderson reluctance generators]
*** frequency controlled by varying shaft speed: frequency = shaft speed * pole pairs
*** dynamic auto-tuning to coil resonance may be difficult
** Three phase vs single phase
*** most reasonably-efficient rotary generators deliver balanced three-phase power, but an induction furnace is a single-phase load
*** this can be addressed with a simple tuned load balancer [http://www.google.com/patents/US3331909], but this may require manual tap- and capacitor adjustments depending on the load
*** alternatively a solid-state static synchronous compensator (STATCOM) can be applied, as described for example in [http://www.strutherstech.com/PDF/STATCOM%20LOAD%20BALANCING.pdf]
*** a combination of the above two methods (carrying most of the load unbalance with fixed capacitors/reactors and using a relatively low-VAR static compensator) might be most economical
** Mechanical power source
*** electric motor (motor-generator set)
*** prime mover (internal combustion or [[Steam_Engine |steam engine]])
*** hydraulic
**** [[Power_Cube |Power Cube]]
**** [[Stationary_Hydraulic_Power |Stationary hydraulic power]]
**** shaft speed control by variable displacement motor or [[Stationary_Hydraulic_Power#Hydraulic_pressure_transformation |hydraulic transformer]]

----
*50 kW for $1600 - [http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200415768835&rvr_id=&crlp=1_263602_263622&UA=L*F%3F&GUID=1357ab741250a0265337bec7ff94d6a7&itemid=200415768835&ff4=263602_263622]
*20 kw STC 3 phase 120 - 480V, also 1 phase - generator - $692 -[http://cgi.ebay.com/20kw-STC-3-Phase-277-480-12-Wire-generator-Head-altern_W0QQitemZ160369799644QQcmdZViewItemQQptZBI_Generators?hash=item2556c8f1dc]
*50 kw STC 3 phase- $1300 - [http://cgi.ebay.com/50KW-STC-3-Phase-12-Wire-generator-alternator_W0QQitemZ160357088416QQcmdZViewItemQQptZBI_Generators?hash=item255606fca0]
**LifeTrac 55 hp can produce 38 kW with this head

===Melt Calculations===
[[Image:inductioncalc.jpg]]

''Note:'' Electrical input requirements may be reduced somewhat by preheating the charge with flame or direct solar energy.

[[Image:imgp4545.jpg|600px]]

Photo I took while visiting a foundry near Santa Fe. Seems relevant!

==Wiki Links==

*[[Foundry]]

*[[Induction Furnace Request for Bids]]

==External Links==
* [http://blog.opensourceecology.org/?p=1373 Original Blog Post]
* [http://web.archive.org/web/20100816034057/http://www.uie.org/webfm_send/391 Technical basics and applications of induction furnace PDF]

==See Also==
{{Induction Furnace}}

[[Category:Induction_Furnace]]

File:Furnace-linings-ferrous-01.pdf

2018-09-02T17:51:13Z

ChuckH: Foseco furnace linings brochure

Foseco furnace linings brochure

CellConcentrationTurbidimeter

2015-01-09T01:31:45Z

ChuckH: /* Sensor Design */

= Cell Concentration Turbidimeter =

This sensor is used in the OSE [[Fermentor]], for example in [[Polylactic_acid|Polylactic Acid Production]]. It provides continuous on-line measurement of cell concentration in the fermentor broth.

== Cell Counting Background ==

During fermentation, real-time monitoring of the cell population is very helpful in process control.

=== Direct Measurements ===
The most important parameter of the process is most commonly live-cell concentration; however this is difficult to measure directly. Possible methods are
# ''Colony counting'': serial dilutions are plated out onto agar and incubated. This is the most widely used reference method but is tedious and cannot provide real-time feedback. Best used as a calibration technique for an alternative real-time method.
# ''Metabolic heat generation'': http://www.sciencedirect.com/science/article/pii/S004060311200278X#bib0105

=== Indirect Measurements ===
In practice, direct measurements are not used for process control; instead, indirect measurements are used to estimate live-cell concentration. Some alternatives:
* '''Total Cell Count'''
# ''Coulter counter'': single-particle electroconductivity analyzer.
# ''Microscopic'': cells are collected on a membrane filter and counted under an optical or electron microscope. This cannot provide real-time feedback, but can be used as a calibration technique for other methods.
A limitation of cell-counting methods is that they do not discriminate living from dead cells.
* '''Turbidimetry'''
The simplest real-time indirect measurement method responds to the cloudiness ("turbidity") of the fermentor broth. When a light beam passes through a broth sample, the cells scatter light out of the beam. In the general case, turbidity can be measured either by looking at the side scatter (nephelometry -- especially useful for very-low-turbidity fluids) or looking at the diminution in main beam intensity (optical density, OD). It is this latter technique that is most accepted in microbiology for estimating cell concentration.

Limitations of turbidimetric methods are that the measured optical signal is dependent on many factors beyond cell count:
# cell species
# cell size distribution
# wavelength spectrum of illumination
# illumination and collection angles of the beam
# suspended solids other than cells
# dissolved materials in the fluid
# gas bubbles

For these reasons the correlation between cell count and optical density must be established by a calibration that is specific not only to the particular instrument in use but also to the cultured species, the growth medium, and operational conditions.

Once a calibration curve is established, a turbidimetric sensor provides consistent information for real-time process monitoring and control, provided the operational conditions correspond to the calibration conditions. This method is widely used in practice. Use of a laboratory spectrophotometer with a 1-cm-path-length cuvette and 600nm illumination wavelength has become a de facto standard. Commonly the optical density (which is the base-10 logarithm of the ratio between illumination intensity and transmitted intensity) is considered proportional to cell concentration over a range of about 0.1 to 0.8 OD.

The calibration constant is usually given as (cells/mL)/(1.0 OD) (even though 1.0 OD is beyond the linear range). As noted above, this value is highly dependent on operational conditions; reported calibration constants for ''E. coli'' vary from 1e8 to 1e10.

== Sensor Requirements ==

For the OSE polylactic acid fermentor, the sensor faces the following conditions and requirements:
# Organism: ''Bacillus coagulans''
# Concentration range: 1e5 to 1e8 cells/mL
# Sensor interface: Arduino, shared with open source bioreactor controller.
# Sensor system cost: less than $100 in parts, including electronics and fluid handling components

== Sensor Design ==

The optical design of a typical laboratory spectrophotometer must meet many challenging requirements which are outside the scope of turbidity measurement; it is therefore overcomplex for a dedicated process sensor. The key optical requirements are
# repeatable narrowband illumination spectrum
# repeatable illumination/collection angular geometry
# ability to compare the sample to a clean "blank"

[[File:LEDSpectrum.PNG|thumb]]
The OSE sensor uses a collimated LED light source with a spectral bandwidth approx. 20nm FWHM centered near 610nm, such as [http://www.kingbrightusa.com/images/catalog/SPEC/WP7113SEC-J4.pdf Kingbright WP7113SEC/J4] (available from DigiKey). At the opposite side of a flow cell, a collimated silicon PIN photodiode such as [http://www.osram-os.com/Graphics/XPic5/00101689_0.pdf/SFH%20213%20FA,%20Lead%20(Pb)%20Free%20Product%20-%20RoHS%20Compliant.pdf Osram SFH213] (also available from DigiKey) receives the light beam. The flow cell is constructed of two parallel glass windows sealed to spacers with silicone adhesive.

A syringe pump, valve, and clean-water source support a cyclical sampling operation in which broth is drawn from the reactor into the flow cell then returned to the reactor followed by a clean-water purge. The photodiode measurement on the sample is compared to the measurement after clean-water purge (the "blank") to obtain an OD measurement.

[[File:turbidimeter.svg|border]]

=Research and Development=
http://starch.dk/isi/papers/JMM%2010%20EB.pdf

http://openwetware.org/wiki/Evolvinator#Calibration

http://opensourceecology.org/wiki/Fermentor/Research_Development#Low-Cost_Microbioreactor_for_High-Throughput_Bioprocessing

Polylactic acid/Research Development

2015-01-06T08:18:02Z

ChuckH: /* Bacillus coagulans */

''We are like dwarfs on the shoulders of giants, so that we can see more than they, and things at a greater distance, not by virtue of any sharpness of sight on our part, or any physical distinction, but because we are carried high and raised up by their giant size.''

=Literature review=
Below is a review of peer reviewed publications and expired patents covering the areas of lactic acid from microorganisms, purification of lactic acid to polymerization grade quality, and methods of a polymerization of polylactic acid. An effort was made to reference sources that are freely available online outside of subscription databases, but in certain areas of recent progress sources requiring subscription are used. The information below informs the rationale of the proposed manufacturing protocol.

==Process Reviews==

====L (+) lactic acid fermentation and its product polymerization====
[http://www.scielo.cl/pdf/ejb/v7n2/a08.pdf L (+) lactic acid fermentation and its product polymerization] (2004) by
Narayanan et al reviews the production of lactic acid and its use as a plastic monomer. The synthetic route of lactic acid is four steps that involve fixating an activator cyanide group to an acetylaldehyde to form lactonitrile, hydrolysis of lactonitrile with sulfuric acid to yield lactic acid and ammonium salt. For purification via reactive distillation lactic acid is esterified with methanol to methyl lactate and water, methyl lactate is distilled, and hydrolyzed to lactic acid with the addition of water. The production of lactic acid from biological sources is through the fermentation of high energy carbohydrates to lactic acid by Lactic Acid Bacteria. Lactic acid is neutralized and precipitated with calcium hydroxide. Calcium lactate is collected and hydrolyzed with water. For purification lactic acid is esterified with methanol to methyl lactate and removed via distillation, before hydrolysis with water. Measurement of lactic acid can be obtained by HPLC, NAD+ colorimetric assay, or gas chromatography, in order of preferability.

Lactic acid bacteria have been extensively studied, particularly lactobacillus used in dairy preparation and lactobacillus species used for lactic acid production include ''Lactobacillus delbreuckii'' subspecies ''bulgaricus'', ''Lactobacillus helveticus'', ''Lactobacillus amylophylus'', ''Lactobacillus amylovirus'', ''Lactobacillus lactis'', ''Lactobacillus pentosus''. Rhizopus oryzae are also stereoselective LAB as well as yeasts such as'' Saccharomyces cerevisiae'' and ''Kluyveromyces lactis'' and have been investigated for their usefulness. Lactase enzymes are stereospecfic and heterolactic species have two isoforms, some species induce their second enzyme only under high concentrations of lactic acid. Certain species also contain allosterically regulated as well as unregulated isoforms. Genetic engineering on ''lactobacilli'' has shown success in controlling stereospecficity of products, reaction rate and yield; ''Rhizopus oryzae'' mutants are also under study. Favorable feedstocks are high sugar or starch plants. Nitrogen sources represent a major cost to the industry with yeast extract demonstrating superior performance to cheaper alternatives.
Techniques to increase yield include pretreatments, simultaneous saccharification, and nutrient supplementation (especially nitrogen - yeast extract).

Different bioreactor configurations have been studied and batch-wise and continuous reactor sketches are provide. Lactic acid fermentation is inhibited by increasing lactic acid concentrations and methods of filtration or pH control by alkali addition are utilized to increase yield. Methods to remove lactic acid product from the fermentation batch include ultrafiltration, ion-exchange resins, and electrodialysis. Continuous cell recycle reactors have shown high performance and utilize membranes to retain cells while removing media. Cell immobilization by biofilm establishment shows higher performance to free floating culture systems. High cell concentrations make it much more difficult to maintain optimal conditions in all parts of the reactor and can stress the cells causing stereoisomerization. Various configurations using plastic chips to increase surface area but gas exchange is a major issue. R. oryzae have a mycelium form which further complicates agitation and gas exchange.

Purification is the major challenge to lactic acid fermentation production and a variety of schemes including membrane separation, solvent extraction, and vacuum distillation. A solvent extraction using a volatile amine weak base (VAWB) is suggested by the author but consumes the volatile reagent during the purification. Table 2 contains information on the various reported polycondensation procedures. Successful polycondensation depends on the proper selection of an azeotropic solvent. Superior polymer properties are reported for ring opening polymerization including higher molecular weight by an order of magnitude, monomer conversion, linearity of product. A catalyst of f 0.05% stannous octoate is suggested. Various processes to increase the sustainability of the process has been investigated including alternatives to salt addition, intensification of membrane configuration, and selection of benign solvents.

====Polylactic acid technolgy====
[http://www.jimluntllc.com/pdfs/polylactic_acid_technology.pdf Polylactic acid technolgy] by Henton (2005) reviews production, purification, and polymerization. Discusses Cargill Dow's plant which is the largest producer at 400,000,000 lb PLA per year and produces over half the market. The plant uses continuous fermentation, preliminary lactide production followed by purification with vacuum distillation and catalytic ring opening polymerization with a tin catalyst. Purification technologies utilize a variety of characteristics of lactic acid to separate it from the broth including filtration, electrodialysis, ion exchange, distillation, liquid and solid extraction, and esterification. Tin octoate is the basis catalyst for lactide polymerization which converts LA to stereospecific form. PLA characteristics include crystallinity which affects Tg and Tm. Life cycle analysis of a accounts for the energy, wastes, and emissions produced in a process and upstream and downstream to measure the sustainable efficacy of the process.

====Development of Four Unit Processes for Biobased PLA Manufacturing====
http://www.isrn.com/journals/ps/2012/938261/ Development of Four Unit Processes for Biobased PLA Manufacturing by Chae Hwan Hong, Si Hwan Kim, Ji-Yeon Seo, and Do Suck Han (2012) obtain lactic acid from E coli and purify and polymerize polylactic acid on a pilot scale. They divide the process into four steps fermentation, separation, lactide conversion, and polymerization. Fermentation is performed by E coli KCTC 2223 on LB media in shaking flasks or a bioreactor, with fermentation pH maintained at 6.4 by addition of ammonium hydroxide. A maximum yield of approximately 50% of the input glucose at 60 g/L of D-lactic acid was obtained. Separation was performed by stacked electrodialyis to obtain concentrated ammonium lactate, followed by water splitting electrodialysis using bipolar and ion specific membranes to obtain pure lactic acid. To polymerize the lactic acid a two step process of lactide production followed by high molecular weight polymerization. Lactide formation started with removal of free water at 85°C in vacuum followed by addition of catalysts (zinc oxide or Sn(OEt)2) with a mass fraction of 1~5%. The temperature was raised to 150°C and maintained until no more water was produced, and the temperature was raised to 235 C for an hour. Zinc oxide was found to catalyze high molecular weight oligomers 7760 g/mol with a yield of 85% in a short period. A ring opening procedure started with drying the lactide at 60 C followed by catalytic polymerization with ~250 ppm tin(II)bis(2-ethylhexanoate) at 180°C and 1 hr was found produce ~150 g/mol polylactic acid.

====A Literature Review of Poly(Lactic Acid)====
[http://naldc.nal.usda.gov/download/4048/PDF A Literature Review of Poly(Lactic Acid)] (2001) by Donald Garlotta.

==Alternative routes==
Microbial is an established and viable route to lactic acid production that is an alternative to the petroleum based racemic producing process, however there are other routes using further engineered organisms or catalyzed direct reactions.

=====Engineering a Cyanobacterial Cell Factory for Production of Lactic Acid=====
[http://www.researchgate.net/publication/230620095_Engineering_a_cyanobacterial_cell_factory_for_the_production_of_lactic_acid/file/79e41502cd9dab3579.pdf Engineering a Cyanobacterial Cell Factory for Production of Lactic Acid] (2012) by S. Andreas Angermayr, Michal Paszota, and Klaas J. Hellingwerf transforms Synechocystis PCC6803 with Bacillus subtilis L-lactate dehydrogenase and transhydrogenase. Expression of the transhydrogenase is deleterious, but coexpression with dehydrogenase mediates the effect and increases lactic acid production. NADH is used as the hydrogen donor and the transhydrogenase is selected to increase the concentration relative to NADPH.

=====Catalytical conversion of carbohydrates in subcritical water: A new chemical process for lactic acid production=====
[http://144.206.159.178/FT/616/601140/12505447.pdf Catalytical conversion of carbohydrates in subcritical water: A new
chemical process for lactic acid production] investigates the effects of different salts on the conversion of hexose and triose under subcritical aqueous conditions with a focus on lactic acid production. Fructose is found to be superior to glucose with a conversion of 48%, while trioses had higher conversion rates, the highest being dihydroxyacetone with 86% (g g−1) conversion. Catalysts tested include Co(II), Ni(II), Cu(II)and Zn(II), with Zn(II) being superior and utilized as ZnSO4. Temperature, and residence time were altered in a range from 200 to 360 C and residence times from 3 to 180 s, and pressure was kept constant at 25 MPa. The experimental setup used two stainless steel reactors (tube 1: i.d. 1.0 mm, length 700 mm, volume 0.55 cm3; tube 2: i.d. 3.0 mm, length 700 mm, volume 4.95 cm3), with temperature control from a heat block and with flux being controlled by an upstream HPLC pumping in substrate. Downstream of the reactor is a heat exchanger to dissipate heat, spill valve to relieve pressure, and three way valve to direct the process stream to waste or product containers. Conversion, yield and selectivity, are calculated. Fructose can be completely degraded within 2 min at 260 C over ZnSO4 catalyst and the time further decreased with an increase in temperature, with 300 C completing conversion within 20 s. Furthermore selectivity increases from ~35% to 48% when temperature is increased from 260 C to 300 C.

==Feedstocks==
Lactic acid production by microorganisms is based on conversion of sugars to a lower energy product (lactic acid) due to an unavailability of oxygen for respiration. Feedstocks containing sugars can come from a variety of sources, but ideally it should not compete with food crops. Sources of sugar rich material that do not compete with food crops include sorghum, degraded lignocellulose, and alternative sources such as lipid extracted algal cake. Lignocellulose contains a large amount of fixed carbon and is available in large amounts as the vegetative tissue of harvested crops but is recalcitrant to degradation. A wide variety of feedstocks can be used and must be optimized to an individual situation.

===Carbohydrates crops===
=====Optimization of Lactic Acid Production from Cheap Raw Material: Sugarcane Molasses=====
[http://www.pakbs.org/pjbot/PDFs/44(1)/49.pdf Optimization of Lactic Acid Production from Cheap Raw Material: Sugarcane Molasses] (2012) by Umar Farooq, Faqir Muhammad Anjum, Tahir Zahoor, Sajjad-ur-rahman, Muhammd Atif Randhawa, Anwaar Ahmed, and Kashif Akram compared lactic acid production of lactobacillus delbrueckii using sugar cane molasses as a feedstock over a range of temperatures and feedstock concentrations. The important characteristics of a feedstock for lactic acid are low cost, minimum contaminants, rapid fermentation rate, high lactic acid production yields, little or no by-product formation and year round supply. The agricultural byproduct of sugar cane includes a molasses that contains 45-60% sugars including sucrose, glucose, and fructose. Lactobacillus delbrueckii was isolated from an indigineous yoghurt population by procedure by Harrigan (1998). Fermenation was carried out at 34ºC, 38ºC and 42ºC with 0, 6, 12, 18 and 24% substrate levels without apparent pH control for 7 days. The media contained (g 100mL-1); peptone 10.0, meat extract 10.0, yeast extract 05.0, Tween-80 01.0, K2HPO4 02.0, Sodium acetate 05.0, tri-ammonium citrate 02.0, MgSO4.7H2O 0.2, MnSO4.4H2O 0.05. Total sugars and lactic acid were measured over the experiment on a 24 hr basis. The highest temperature of 42 C was the most productive. The second highest substrates concentration, 18%, achieved the highest lactic acid concentration 11.27 g/ 100 ml, yield 85%, and productivity achieving peak sugar usage on the 3rd day.

===Lignocellulose===

=====Fermentable sugars by chemical hydrolysis of biomass=====
[http://www.pnas.org/content/107/10/4516.full Fermentable sugars by chemical hydrolysis of biomass] (2010) by Joseph B. Binder and Ronald T. Raines utilized an ionic liquid, 1-ethyl-3-methylimidazolium chloride (Emim)Cl, with an acid catalyst, HCl and H2SO4 to demonstrate efficient hexose and pentose release from cellulose and lignocellulose biomass. The process is further improved through the slow addition of water to drive the reaction toward glucose formation over degradation products despite the hydrophobicity of cellulose. The corn stover was first treated with Emim before addition of HCl and water. With the addition of water being gradually increased to 43% over 1 hour the glucose yields were increased to 90%. The hydrolysate was run over an ion-exchange column and the resulting conversion product was used as a feedstock for E coli and yeast and performed equitably with an insignificant trend towards better performance by the hydrolysate under low oxyygen conditions. The major cost of the process is in the column chromatography step. The authors speculate on better performing biocatalysts that utilize pentoses (such as Bacillus coagulans).

=====A Study of the Acid-Catalyzed Hydrolysis of Cellulose Dissolved in Ionic Liquids and the Factors Influencing the Dehydration of Glucose and the Formation of Humins=====
[http://www.cchem.berkeley.edu/atbgrp/files/ChemSusChem%202011%204%201166.pdf A Study of the Acid-Catalyzed Hydrolysis of Cellulose
Dissolved in Ionic Liquids and the Factors Influencing the Dehydration of Glucose and the Formation of Humins]

=====Hydrolysis of lignocellulosic materials for ethanol production: a review=====
[http://stl.bee.oregonstate.edu/courses/ethanol/restricted/SunCheng2002.pdf Hydrolysis of lignocellulosic materials for
ethanol production: a review] (2002) by Ye Sun, Jiayang Cheng.

====Detoxification of dilute acid hydrolysates of lignocellulose with lime====
[http://www.ncbi.nlm.nih.gov/pubmed/11312706 Detoxification of dilute acid hydrolysates of lignocellulose with lime]

===Microalgae===

=====Nannochloropsis salina biomass to lactic acid and lipid=====
[http://www.sciencedirect.com/science/article/pii/S1369703X1200191X# Nannochloropsis salina biomass to lactic acid and lipid] (paywalled) by Talukder and Wu examines the suitability of oleaginous Nannochloropsis algal cake after lipid extraction for lactic acid production by Lactobacillus pentosus.

==Lactic acid bacteria==

Choice of lactic acid producing microorganism must take into account a number of factors including productivity, stereoisomer production, feedstock flexibility, difficulty culturing - including contamination. Lactic acid production for fermentation is not an uncommon capability including human muscle tissue. A number of microorganisms with prodigious lactic acid production have been isolated and characterized and include well-known members of the lactobacillus genus such as acidophilus and delbrueckii, bacillus bacteria such as bacillus coagulans, and some fungi such as Rhizopus oryzae. Choosing an organism and strain that with high lactic acid productivity needs to consider the molecular information available on these strains as many are under intense study. Lactobacillus exist as many well established strains that are well characterized from their use in yogurt making and early adoption to the lactic acid production industry, while bacillus coagulans has recently been identified in a number of environmental isolation efforts and is now under intense study with multiple strain genomes being recently sequenced. Organisms are available with a variety of licenses from biological specimen supplier American Type Culture Collection (ATCC).

====Bacillus coagulans====
Bacillus coagulans has been an organism of recent research focus due to its possible applications in biomass conversion. To further this work genome sequencing has been performed by American and Chinese research groups e.g. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3905273/ and draft sequences have been published http://www.ncbi.nlm.nih.gov/genome/?term=CP002472 [http://genome.jgi.doe.gov/?core=genome&query=Bacillus%20coagulans&searchType=Keyword&showAll=false&showGroups=true&externallySequenced=true&sortBy=displayNameStr&showRestricted=true&showOnlyPublished=false&showSuperseded=true&sortOrder=asc&rawQuery=false&showFungalOnly=false&programName=all&programYear=all&superkingdom=--any--&scientificProgram=--any--&productName=--any--&start=0&rows=50 JGI]. There is a D-LA dehydrogenase gene present that functionally expresses in E coli, but there is no detectable endogenous activity most likely due to nonexpression. B. coagulans has been isolated a number of times from the environment based on lactic acid productivity and it is under intense study for application due to its thermotolerant growth and robustness. Bacillus coagulans thermophilic nature not only removes the necessity of a sterilization of feedstock, but it overlaps with fungal lignocellulases optimal temperature and pH giving possibility to using low value lignocellulose agricultural byproducts. Bacillus coagulans is related to a well studied organism Bacillus subtilis and its molecular biology is being characterized. Plasmid transformation using electroporation has been described and vector sequences for a B coagulans/ E coli plasmid.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3165500/pdf/zjb4563.pdf
http://genome.jgi-psf.org/bacco/bacco.home.html

=====Non-Sterilized Fermentative Production of Polymer-Grade L-Lactic Acid by a Newly Isolated Thermophilic Strain Bacillus sp. 2–6=====
[http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004359 Non-Sterilized Fermentative Production of Polymer-Grade L-Lactic Acid by a Newly Isolated Thermophilic Strain Bacillus sp. 2–6] by Qin et al examines Bacillus coagulans lactic acid fermentation capacity in batch and fed-batch mode with unsterilized feedstock. The strain was newly isolated and high productivity and optical purity was achieved in both cases suggesting it may be a promising organism for lactic acid fermentation. The productivity obtained are higher than other reported strains. The report obtained 730 isolates at 55 C growth from 7 soil samples and the 2-6 strain was selected as the most productive lactic acid producer. Bacillus coagulans identity was assigned based on 16S rRNA gene sequence and an enantiomeric ratio of very high L:D enantiomers. NAD-dependent lactate dehydrogenase activity could was only detectable for the L-lactate dehydrogenase through active stained native PAGE, demonstrating enzymatic activity is entirely L-lactic specific. Initial screens utilized 97 g/L glucose and higher glucose concentrations were examined for higher productivity. Concentrations of glucose above 133 g/L were found to inhibit glucose consumption and lactic acid productivity and 97 g/L and 133 g/L glucose concentrations were used for further optimization. The nutrient requirements of the strain for nitrogen source and vitamins were investigated and the most cost effective media components of glucose 97–133, YE 12.6, soy peptide 1.2, cottonseed protein 3, NaNO3 1, NH4Cl 1, were found to produce 95% of maximum yield. Two phases of lactic acid production were identifiable in batch mode from 0-15 hour during which cell growth and lactic acid productivity were coupled and 15-30 hours when cell density reached stationary phase and lactic acid production continued to complete consumption of the glucose, albeit at a slower rate. Three fed-batch regimes were tested and the effectiveness of continuous feeding and pulse feeding were found to be superior to exponential feeding. Fed-batch experiments were conducted in 5 l and 30 l volumes with no noticeable differences in rates or products. Analysis of organic acid products using organic acid HPLC columns revealed no other detectable products. Overall, Bacillus coagulans strain sp 2-6 is a highly promising strain for the production of enantiomeric pure lactic acid in an industrial process.

=====L(+)-Lactic acid production from non-food carbohydrates by thermotolerant Bacillus coagulans=====
[http://www.springerlink.com/content/a846520t8g026738/fulltext.pdf | L(+)-Lactic acid production from non-food carbohydrates by thermotolerant Bacillus coagulans] by Ou et al examines the ability of Bacillus coagulans 36D1 to utilize carbohydrates from lignocellulosic materials treated with fungal lignocellulases. Lignocellulose materials could be a low cost source of sugars, but there are several limitations to implementation of an efficient industrial process, mainly the cost of treatment to breakdown recalcitrant lignocellulose material, complex product mixture produced by many microorganisms in industrial use, and low yield of desired products by homolactic organisms. Bacillus coagulans displays traits that may allow it to overcome these hurdles to adoption of biocatalytic lignocellulose lactic acid production. As a thermophilic organism with a growth temperature of 50-55 C and favors slightly acidic conditions lignocellases are not inhibited during simultaneous fermentation allowing a decrease in the amount of costly enzymes. Coagulans consumes the released hexoses and pentoses relieving product inhibition and creating a productive pathway. Coagulans possesses the pentose-phosphate pathway for efficient use of pentose sugars unlike other industrially known strains which possess the phosphoketolase pathway resulting in equimolar production of acetic acid and lactic acid (lowers efficiency and complicates purification). Despite its apparent advantages coagulans titer of lactic acid (depending on the strain and conditions) is often lower than is reported for other lactic acid bacteria. This study utilized salting out of the lactic acid product using calcium carbonate (CaCO3) and demonstrated titers of over 100 g/L.

=====Engineering Thermotolerant Biocatalysts for Biomass Conversion to Products=====
[http://www.osti.gov/bridge/servlets/purl/979455-cpKL66/979455.pdf Engineering Thermotolerant Biocatalysts for Biomass Conversion to Products] a technical report by K. T. Shanmugam, L. O. Ingram & J. A. Maupin-Furlow describes progress on characterizing B coagulans metabolism.

====Bacillus genetic transformation====

=====Development of plasmid vector and electroporation condition for gene transfer in sporogenic lactic acid bacterium, Bacillus coagulans=====
[http://download.bioon.com.cn/view/upload/month_0906/20090616_8a78ff4923330e867f1eOFHGOoTkD5Hq.attach.pdf Development of plasmid vector and electroporation condition for gene transfer in sporogenic lactic acid bacterium, Bacillus coagulans] (2007) by Mun Su Rhee, Jin-woo Kim, Yilei Qian, L.O. Ingram, K.T. Shanmugam contructs a plasmid Being of the same genus as the laboratory model organism Bacillus subtilis may allow the utilization of a number of laboratory plasmids to be platforms for coagulan optimization. Comparable G-C content appears to be the major limiting factor in interspecies transformation in the bacillus genus.

=====Interspecific Transformation in Bacillus=====
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC278154/pdf/jbacter00454-0221.pdf Interspecific Transformation in Bacillus]
by Julius Marmur, Edna Seaman, James Levine

Plasmid maintenance often requires continuous application of a selection pressure or else the unnecessary plasmid is jettisoned or lost during replication. Further research is needed into methods of genomic integration through homologous recombination/ strand break repair integration or protoplast transfer. Alternatively, genetic mutants with interruptions to necessary nutrient pathways can be obtained and the reintroduction of nutrient genes reintroduced as a marker.
http://www.google.com/patents?hl=en&lr=&vid=USPAT5843720&id=2eYAAAAAEBAJ

====Lactobacillus====
Lactobacillus is the lactic acid fermenator used in the production of fermented foods (from yogurt to sourdough) and has been used in the industrial fermentation of lactic acid. It produces a racemic mixture of D/L-lactic acid, but its growth characteristics are well known and its productivity is high enough to be profitable.

=====Biotechnological Production of Lactic Acid and Its Recent Applications=====
[http://www.aseanbiotechnology.info/abstract/21021670.pdf Biotechnological Production of Lactic Acid and
Its Recent Applications]

=====Optimisation of media and cultivation conditions for L(+)(S)-lactic acid production by Lactobacillus casei NRRL B-441=====
[http://download.bioon.com.cn/upload/month_0811/20081102_df48a9c25ad1c920285eJ4RBX4RJnzRY.attach.pdf Optimisation of media and cultivation conditions for L(+)(S)-lactic acid production by Lactobacillus casei NRRL B-441] (2001) by M. Hujanen, S. Linko, Y. Y. Linko, M. Leisola uses fed batch shaking flask fermentation of glucose with Lactobacillus casei using malt extract as a nitrogen source. Lactobacillus casei was chosen for its favorable sterioisomer ratio and the study aimed to optimize the fermentation process using industrially relevant growth conditions with a low cost nitrogen source. Maximum concentration obtained was 118 g/L from 160 g/L glucose and maximum productivity of 4.4 g/L/h was achieved at 100 g/L glucose at 15 hours fermentation. Malt sprout extract to glucose in a ratio of 53.8:100 was used throughout the study for a standard amount of nitrogen:carbon 22:100. Growth was conducted 1.5 l bioreactors at 35 °C, pH 6.3, 200 rpm, with pH adjustment by NaOH addition. Lactic acid and glucose were determined by HPLC using an Aminex HPX-87H+ cation-exchange column and consumption of glucose and the production of lactic acid was monitored with a YSI 2700 Select Biochemistry Analyzer. Malt sprout extract used as sole nitrogen source was found to show a loss in productivity but could be effectiviely used to supplement reduced concentration of yeast extract, down to 4 g/L. Resting fermentation was also conducted but showed a slight loss in productivity.ided by fermentation time). The maximum productivity with yeast extract was 6.0 g l at 16 h fermentation time compared to 4.9 g/l/g at 16 h by malt sprout extract and resting cells were 3.5 g/l/h.

=====Comparison of lactobacillus delbrueckii and bacillus growth and lactic acid productivity=====
[http://www.sciencedirect.com/science/article/pii/S0141022906000329# Comparison of lactobacillus delbrueckii and bacillus growth and lactic acid productivity. (paywalled)]

====Rhizopus oryzae====
=====L(+)-lactic acid production by pellet-form Rhizopus oryzae R1021 in stirred tank fermenter=====
[http://144.206.159.178/FT/158/86077/1455313.pdf L(+)-lactic acid production by pellet-form Rhizopus oryzae R1021 in stirred tank fermenter] by Bai et experimented with growth parameters effects on culture growth in a continuous run fermentor. Parameters under study included NH4NO3 concentration, CaCO3 addition timing, agitation speed and aeration rate, and inoculation concentration and effects on growth morphology and lactic acid were studied. Pellet form exhibits higher lactic acid productivities and inoculation of 10e6 spores/ml and addition of CaCO3 at 8 hours exhibited pelleted forms. Lactic acid yield was ~72.5% and with 300 rpm and aeration of 0.6 vvm yield increased to 74.5%. Biomass is limited by oxygen transfer, high biomass is necessary for high turnover of glucose to lactic acid. Biomass to lactic acid productivity was found to be highest with 2 g/l NH4NO3, 100 g/l glucose, 300-600 rpm, and 0.6-1.2 vvm. Repeated cycles using the R. oryzae culture showed sustained viability through the 7th cycle and an increase in lactic acid yield to 80%.

=====Optimization of lactic acid production with immobilized Rhizopus oryzae=====
[http://www.academicjournals.org/ajb/full%20text/2012/26Apr/Tanyildizi%20et%20al.htm Optimization of lactic acid production with immobilized Rhizopus oryzae] (2012) by Muhammet Şaban Tanyıldızı*, Şule Bulut, Veyis Selen and Dursun Özer uses polyurethane foam as a matrix and alters basic fermentation conditions.

==Lactic acid production and purification==

Early purification methods involved precipitation of a lactate salt, filtration, and hydrolysis back to lactic acid. This method had high recovery rates, but it produced large amounts salt waste (calcium sulfate) and consumed large amounts of chemical substrates (calcium hydroxide and sulfuric acid). Alternatively other salts could be used that produce a waste that is easier to handle and recover, and under consideration is the universal base sodium hydroxide.

Lactic acid cannot be easily distilled in high purity, but an ester with a small chain organic alcohol can be separated from impurities over a moderate sized distillation column. Reactive distillation of an ester of methanol and lactic acid over a 20 stage distillation column yields high purity ester that can be hydrolyzed back to the acid form. This process is capital and energy intensive, but it gains efficiency in large scale production. The process should be investigated for feasibility and efficiency on a small scale.

Lactic acid must be purified in high quality from the fermentation media in order to be suitable for polymerization. Advances in purification have involved semipermeable membrane sieves and more recently electrophoresis technology. Electrodialysis has been widely adopted for large scale organic acid production. A commercialized route of lactic acid production for polymerization from fermenation uses conventional electrodialysis to separate and concentrate the lactate salt (a basic waste stream can be recycled to the fermentor), followed by watersplitting ED with bipolar membranes to produce a highly concentrated lactic acid. Another method to eliminate the use of a pH balancing base and the production of a waste salt is size selective microfiltration, ultrafiltration and nanofiltration in a crossflow configuration.

http://www.sciencedirect.com/science/article/pii/S0960852412014460 Open fermentative production of l-lactic acid by Bacillus sp. strain NL01 using lignocellulosic hydrolyzates as low-cost raw material (paywall)

====Membrane separation====

=====Process intensiﬁcation in lactic acid production by three stage membrane integrated hybrid reactor system=====
[http://www.sciencedirect.com/science/article/pii/S0255270112002516# Process intensiﬁcation in lactic acid production by three stage membrane integrated hybrid reactor system] describes lactic acid fermention without alkali addition by the constant removal broth and separation through microfiltration and two stage nanofiltration. Innovative use of size /salt selective membranes to separate lactic acid from the fermentation broth utilizes pressure and crossflow filtration to with microfiltration and two stage nanofiltration (NF-1 and NF-2 membranes manufactured by Sepro) to produce high quality (96%) grade lacic acid. The author claims significant gains can be made in productivity and utilized a highly available feedstock of sugar cane water. The physical formulas of crossflow filtration and economic impact of widespread implementation are proposed. Membrane filtration is shown to be less energy demanding in addition to not producing significant waste. Avoiding the phase changes present in the current industrial salting out method leads to membranes significant energetic and capital cost reductions. L(+)-homolactic acid lactobacilli dulbreike is used as a biocatalyst, achieved high yields, and is available from ATCC. The fermentation broth must be sterilized before fermenation and is maintained at 40 C. Procedural techniques also are presented including: a 15 hour lag phase before fermentation broth is started through filtration, and gradual increase in up to ~16 kg/cm2 pressure driving the polishing NF-1 step over the first 12 hours as a means to reject undissociated lactate while allowing lactic acid passage. The nanofiltration stage with NF-2 membranes is conducted at 13 k/cm2. The authors convincingly argue this process intensification can be conducted on a small scale, possibly even based on solar power.

=====Process intensification in lactic acid production: A review of membrane based processes=====
[http://www.sciencedirect.com/science/article/pii/S0255270109001986 Process intensification in lactic acid production: A review of membrane based processes] (pay-walled) (2009) by Pal et al reviews membrane based separation advances in lactic acid purification. The broth contents that need to be separated are cells, nutrients, unconverted carbon, water, and lactic acid and membrane based approaches include microfiltration, ultrafiltration, nanofiltration, reverse osmosis and electrodialysis. Separation based on size from larger to smaller pore size is through microfiltration, ultrafiltration, then nanofiltration. Cells and proteins are the main causes of membrane fouling and system design needs to minimize their adsorption. Microfiltration (pores 0.1-1.2 microns) retains cells and allows other broth components to permeate. Nanofiltration (pores no larger than 0.1 nm) has been shown to be able to retain sugars while allowing lactic acid to permeate. Research has focused on coupling these two membranes to effectively separate lactic acid while allowing cell and sugar recycle in a continuous operation fermentor. Pressure is needed to drive flux, low pressure (1–2 kgf/cm2) for microfiltration, and higher pressure (6–15 kgf/cm2) for nanofiltration. PH and cross flow velocity have been identified as a key parameter for fluxes with an increase in both corresponding to an increase in flux. A variety of membrance configurations have been tested including tubular, frame and plate, and hollow fiber modules. The highest performance ultrafiltration unit reported is by Sikder et al with a laboratory-synthesized polysulfone-cellulose acetate blend microfiltration membrane in a cross flow configuration (see below: Synthesis and characterization of cellulose acetate-polysulfone blend microfiltration membrane for separation of microbial cells from lactic acid fermentation broth).

[[File:EP0393818A1_fig1.png|200px|thumb|right|General process overview]][[File:EP0393818A1_fig2.png|200px|thumb|right|Detailed view of electrodialysis configuration]]
=====Production and purification of lactic acid=====
[http://www.freepatentsonline.com/EP0393818.pdf Production and purification of lactic acid] European Patent EP0393818A1 issued to Glassner and Datta of the Michigan Biotechnology Institute on October 24 1990 details a commercialized route of lactic acid production from fermentation bacteria. The process uses Lactobacillus acidophilus (ATCC 53681 which cannot be located in the [http://www.atcc.org/ ATCC catalog] fed with corn steep liquor and corn oil and reports yields of 80% of the theoretical maximum, with low contamination in the order of less than 1% protein and 10 ppm sulfate ions. The process adds a salt to form lactate complexes which is processed with conventional electrodialysis to create a cell free concentrated lactate salt stream and a dilute broth which is returned to the fermentation chamber. The lactate stream is concentrated through evaporation and processed to a relatively concentrated and purified fraction using water splitting electrodialysis. Strong acid followed by weak base ion-exchange columns are used for polishing to create a purified product of polymerization grade. The process was tested on small 1-2 l, pilot 80 l, and large 500 l scales and productivity and efficiency remained constant as correlated to substrate density and cell density (margin between cell growth versus LA production). The process was tested with continuous batch and cell recycle fermentation. The process is reported to have several advantages including high productivities and recovery rates, low energy requirements (~0.5 kwhr/ lb LA), the possible reuse of salt anion and cation after recovery from the electrodialysis unit, and the dual use of electrodialysis to separate cells from whole broth for recycle without compromising the purity or efficiency of the electrodialysis step.
The process details are as follows. A fermentation media containing 1.0-4.0% steep corn liquor and 0.1-1.0% crude corn oil were combined in water, the concentration of carbohydrates is 20-120 g/l and preferably 40-100 g/l. the media is sterilized and inoculated with 5% inoculum. Growth conditions are maintained with agitation at 75 rpm and a temperature between 20-50 C, and preferably 39 C. The media pH is maintained between 4.8 and 5.7 through the addition of carbonates or hydroxides, preferably sodium or ammonium hydroxide. At a cell concentration of 2.5E10-3.0E10 high lactate productivities can be maintained in the order of 2.0-2.5 g/l/hr with a product concentration of approximately 75-90 g/l. Continuous culture fermentation was conducted in seal flasks using a peristaltic pump to remove broth and additions of an equal volume of fresh broth and salts. A cell recycle fermentor consisted of a growth chamber, a 0.2 micron ultra-filtration unit that returned cells to the chamber, and an effluent capturing container. Whole broth was filtered through 200 mesh to remove debris before direct addition to the electrodialysis chamber.
The conventional electrodialysis unit consists of 8 stacks of anion and cation permeable membranes with a total surface area of 102.4 cm2. The electrolyte used was 2.5 M NaOH. A representative configuration is displayed in figure 2, however adaptions may be made by the user. The configuration displayed contains distribution flow gaskets (18), anion permeable membranes (19), cation permeable membranes (20), parallel cells (21) consisting of 18+19+20, and end cells (22 and 23) consisting of 19+20+ end caps (24). End cell 22 is connected to the cathode (25) via the a connector (27), and end cell 23 is connected to the anode (26) through a connector (28), both end cells are connected to a rinse system that circulates a electrolyte solution (such as NaSO4 or lactate salt). Fermentation broth is passed through a screen (13) and passed to the electrodialysis unit via line 14, basic solutes are passed through the parallel cells and returned to the fermentor through a continuation of line 14. Line 15 circulates a lactate salt solution in the parallel cells and lactate from the broth is concentrated through the anion permeable membranes (19) and collected on the effluent side of the system. The collected effluent is further concentrated via evaporation.

=====Process development and optimisation of lactic acid puriﬁcation using electrodialysis=====
[http://144.206.159.178/FT/549/63720/1083859.pdf Process development and optimisation of lactic acid
puriﬁcation using electrodialysi] by Madzingaidzo et al examines purification of lactic acid from fermentation broth using mono and bi-polar electrodialysis. A mono-polar membrane selectively allows cations or anions to traverse the layer, while a bi-polar layer is made of a cation and anion membrane that splits water molecules into H+ and OH- for charge balancing. An electrical current is applied to the dialysis chamber to separate molecules according to their charge and mono and bi-layer membranes create channels concentrated with certain components. In mono-layer electrodialysis a alternating semipermeable membranes starting with a cation membrane next to the anode (+), a dilute stream feeds through center from which lactic acid is concentrated through a anion exchange membrane towards the anode. Charge is balanced from an electrode rinse solution that circulates next to the electrodes. A bi-polar uses bi-polar membranes to separate the electrode rinse solution from the concentrating channels creating sections holding a base, salt and final acid form. A measurement of % current efficiency (current used to transport molecule from input to concentrated stream/ total current) is used to evaluate the process.

*Reverse osmosis

=====Sources still to be summarized=====
[http://www.sciencedirect.com/science/article/pii/S0011916409008996 Synthesis and characterization of cellulose acetate-polysulfone blend microfiltration membrane for separation of microbial cells from lactic acid fermentation broth] (paywalled)

[http://144.206.159.178/FT/986/206651/5195502.pdf] An electrokinetic bioreactor: using direct electric current for
enhanced lactic acid fermentation and product recovery

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC203522/pdf/aem00131-0098.pdf Novel Method of Lactic Acid Production by Electrodialysis Fermentation

[http://oatao.univ-toulouse.fr/2918/1/Bouchoux_2918.pdf http://oatao.univ-toulouse.fr/2918/1/Bouchoux_2918.pdf]

http://www.sciencedirect.com/science/article/pii/S0011916411010290# Separation of lactic acid from fermentation broth by cross flow nanofiltration: Membrane characterization and transport modelling (paywall)

http://link.springer.com/article/10.1007%2Fs10098-011-0448-z?LI=true (paywall)

====Reactive Distillation====

=====Lactic acid purification=====
[[File:US2350370.png | 200 px | thumb | Right | US patent 2,350,370 ]]
[http://www.google.com/patents/US2350370 Lactic acid purification] issued to Schopmeyer June 6 1944 covers a method to purify lactic acid from fermentation broth by the use of calcium carbonate salts and esterification with methanol for fractional distillation. The fractional distillation set-up includes a boiler containing methanol and lactic acid and a catalyst (H2SO4) that delivers vapors to a fractionation column that allows the separation of a concentrated lactic acid liquor of ~10-50%. The salting out of calcium lactate uses calcium sulfate which is concentrated and converted to acid form through treatment with sulfuric acid, calcium sulfate forms an insoluble fraction. The concentration was usually 40-60% lactic acid and ethanol can also be used as the esterification. The esterification procedure uses a steam jacket with the following substrate mole ratio 1.5:1:0.005 methyl alcohol: lactic acid: sulfuric acid. Start-up of purification uses 80% lactic acid substrate (depending on concentration), 20 methanol, and a small amount of catalyst. Steady-state is maintained by addition of substrates and catalyst, and recycling of methanol.

=====Optimization of Batch Reactive Distillation Process: Production of Lactic Acid=====
[http://www.aidic.it/escape20/webpapers/34Edreder.pdf Optimization of Batch Reactive Distillation Process: Production of Lactic Acid] by Edreder (2010) develops a model for esterifying lactic acid with methanol and distills the methyl lactate, the lactic acid is recovered by hydrolysis. The purity analyzed was 80-99% molefraction, it took 4 refluxes to theretically reach the highest purity.

=====Recovery of lactate esters and lactic acid from fermentation broth=====
[http://www.google.com/patents/US5210296 Recovery of lactate esters and lactic acid from fermentation broth]
issued to Cockrem et al details a method for continuous recovery of lactic acid from fermentation broth using reactive distillation with an alcohol.

====Solvent Extraction====

http://www.google.com/patents/US4771001 Production of lactic acid by continuous fermentation using an inexpensive raw material and simplified form of purification issued to Bailey et al on September 13 1988 deals with a method for production of lactic acid from a the raw sugar source whey permeate and purification solvent extraion. The operational advantage of such a system is the high cell densities that can be achieved and maintained however this raises the challenges of preventing fouling particularly for membrane based cell recycling.

==Polylactic acid polymerization==

====Melt–solid polycondensation of lactic acid and its biodegradability====
[http://www.sciencedirect.com/science/article/pii/S007967000800097X Melt–solid polycondensation of lactic acid and its biodegradability] T. Maharanaa, B. Mohantyb, Y.S. Negi examines the developments in polycondensation formation of PLLA with a set of 4 catalysts. With a decade of research into the technique the reaction dynamics and structure of different stereoisomers has been examined by many investigators. The polycondensation polymerization routes is being investigated for its lower cost and capital investment over the ring opening procedure despite initially producing a polymer of less desirable parameters, such as high melt viscocity, discolorization, and difficulty achieving high molecular weight products. Tin oxide formed from tin chloride with a protonic acid (such as p-toluenesulfonic acid - TSA) is a potent catalyst that can be used in such low concentrations that purification isn't necessary. The polymerization mechanism model originally proposed by Moon involve the coordination of terminal carboxyl condensation with the hydroxyl group on the center carbon. TSA may not be catalytically involved in the reaction, but it may occupy a tin catalytic site to increase the favorability of the desired reaction over side reactions. The reaction can achieve high molecular weight PLLA (ca. 105 Da) by the catalysis of tin(II) chloride dihydrate with an equimolar amount of TSA within 35 h under 0.13–2.66 kPa pressure and within a temperature range of 180–200 C with an average yield of 67%. TSA evaporates during the process and a second addition can further assist the reaction. Solid state polymerization uses temperatures above Tg, but below Tm and sometimes plasticizers to increase terminal end mobility (reaction substrate) to form PLA of high MW with desirable properties.

====Syntheis and Properties of High Molecular Weight Poly(Lactic Acid) and its resulting fibers====
[http://www.cjps.org/EN/article/downloadArticleFile.do?attachType=PDF&id=11239 Syntheis and Properties of High Molecular Weight Poly(Lactic Acid) and its resulting fibers] by Zhang and Wang tests the polylactic acid polymerization melt/solid polycondensation process with a number of catalysts. The now commercial route uses a first step of azeotropic dehydration with reflux, in a high boiling point, aprotic solvent like diphenyl ether to produce 50 kDa polymers. The second step joins these fibers with reduced pressure and a tin and protic acid catalyst. This study uses SnCl2·2H2O/p-toulenesulfonic acid monohydrate (TSA) and SnCl2·2H2O/maleic anhydride catalyst for the first step and TSA in the second step. This improves upon Moon et al. with the addition of TSA in the second step because the environmental polarity was found to be shifted in the first step. Polymer MW had leveled off in step 1, but it continued in step 2 with the addition of more catalyst (TSA). SnCl2·2H2O/maleic anhydride was found to be a more effective catalyst due to the less crystalline nature which allowed further polymerization in the amorphous regions. An increase in reaction temperature for the second step was found to be effective up to 180 C and degradative at higher temperatures. The process starts by combining 400 g distilled lactic acid is with the designated catalyst (0.5% wt SnCl2·2H2O and 0.4% wt TSA or maleic or succinic anhydride)and sealed in the reactor. The reaction is heated to 150 C 4 hrs , the reaction is then heated to 160 C and the pressure reduced to 500 Pa for 4 hrs. After an initial low-weight polymerization the reflux condenser is removed and 0.4% wt (of starting lactic acid) TSA is added to the reactor. The temperature is further increased to 180 C and the pressure reduced to 300 Pa for 10 hrs. The polymerization product was dried and processed used standard melt spinning procedures before a final draw between 150-200 C under nitrogen. The final fiber product was characterized with FTIR, DSC, an Ubbelohde viscosimeter, and tensile-testing machine. Final spinning produced a fiber made of high molecular weight polymers and has high tensile strength.

====Melt/solid polycondensation of l-lactic acid: an alternative route to poly(l-lactic acid) with high molecular weight====
[http://144.206.159.178/FT/862/34857/596552.pdf Melt/solid polycondensation of l-lactic acid: an alternative route to
poly(l-lactic acid) with high molecular weight] by Moon et al (2000) describes a method that yields high weight PLA on the order of 500,000 daltons through a condensation reaction using a tin chloride dihydrate/p-toluenesulfonic acid binary system. They report that reaction temperatures below the Tm (melting point) of PLA yields a better product and is referred to as melt/solid polycondensation. oligo(l-lactic acid) (OLLA) is mixed with tin(II) chloride dihydrate (SnCl2) (0.4 wt% relative to OLLA) and p-toluenesulfonic acid (TSA) (an equimolar ratio to SnCl2). The mixture is heated to 180 C and the pressure reduced to 10 torres over the period of an hour followed by maintenance for 5 hrs. The product consisting of 20,000 dalton polymers is ground and heated to 105 C under vacuum for 1-2 hr to crystallize the polymers. Solid-state post-polycondensation was initiated by increasing the temperature to 150 C and reducing the pressure to 0.5 Torr. Treatment was continued over 30 hours, but molecular weight peaked between 2-10 hours and drastically reduced after 20 hours. The results showed a method to obtain high molecular weight PLLA with comparable characteristics to the lactide ROP synthesis. The method used here catalyzes the first step of dehydration to form lactide and the lactide ROP step follows. The high activity of the catalyst and the ability to move through the amorphous PLLA may be driving the reaction by concentrating ester tails and catalyst in the amorphous regions during crystallization.

====Basic properties for film polylactic acid produced direct condensation polymerization of lactic acid====
[http://www.csj.jp/journals/bcsj/J-STAGE/6808/pdf/68_2125.pdf Basic properties for film polylactic acid produced direct condensation polymerization of lactic acid] by Ajioka characterizes the polylactic acid products of different catalysts and solvents under 130-250 C. Polymerization was commercially pursued from an isolated dilactide intermediate, but direct polymerization is possible due to improvements in kinetic control, removal of resulting water, and suppression of depolymerization. Solvents controlled the rate of reaction based upon their boiling point and the ability to remove water and a Dean Stark trap used, diphenyl ether results shown. Tin and protonic acids catalysts were found to have superior performance with tin(II) chloride achieving highest efficiency and high molecular weights. Zinc catalysts produced maximum 150 kDa weight polymers at 160 C. Weights and flow rates comparable to dilactide process and usable for injection molding. D and L enantiomers were polymerized in ratios of 50/50 to 0/100 respectively. Pure L form had the highest strength and molecular weight. 13C NMR of direct condensation PLA showed 5 carbonyl signals, an additional lower signal from adjacent L subunits. <br />
Direct synthesis of PLA general protocol <br />
In a reaction chamber with a Dean Stark trap 40.2 g 90% lactic acid and 0.14 g tin were dissolved in 400 ml organic solvent for 2 hr at 140 C. The trap was replaced with a tube containing 40 g molecular sieve (3 A) for azeotropic separation for 20 to 40 hr at 130 C. At half volume 300 ml chloroform was added and catalyst removed with filtration or extraction. PLA product was by precipitation by 900 ml methanol and washing over suction with methanol. <br />
Cyclic oligomer production <br />
10.0 kg of 90% lactic acid azeotropically dried 81.1 kg diphenyl-ether organic solvent with 6.2 kg tin catalyst at 150 C for 2 hr. This was followed by recycling of solvent using 4.6 kg molecular sieve (3 A) for 40 hr at 140 C. The reaction was concentrated to 70 kg, cooled to 40 C, and PLA crystals collected. The reaction was concentrated to 5.8 kg. A 11.6 kg hexane was added to the filtrate and an oil separated with 5.8 kg acetonitrile and 1 M HCl. An oily substance was collected after 30 min of agitation and washed with 5.8 kg water. The washed product was dissolved in 2.9 kg chloroform and combined with 4 l isopropyl alcohol and a final precipitated product collected over suction and dried with reduced pressure. Final yield 350 g.

====Synthesis of polylactic acid by direct polycondensation under vacuum without catalysts, solvents and initiators====
Synthesis of polylactic acid by direct polycondensation under vacuum without catalysts, solvents and initiators by Achmad et al details a procedure. The authors recommend PLA be pursued using processing plants capable of fermenting feedstock, purifying lactic acid, and condensing the product as is proposed for the OSE product ecology. Streptococcus bovis is a LAB suggested for use, but the species is also linked to pathogenicity. The process used by the researchers used three phases for treating the lactic acid and polymerizing its monomer: distillation, oligomerization, and polymerization. The reaction was carried out in 4 l sealable flasks, on magnetic stirrers and heaters, with temperature and pressure probes, and connected to a pressure regulator. During distillation sample temperature is brought to 150 C over 90 minutes and maintained for 60 minutes and PLA concentration increases from 90% to 100% as measured by acid-base titrations. Oligomerization phase was a reduction in pressure to 10 mmHg and temperature was raised to 200 C. The polymerization step was maintenance of the reduced pressure and temperature for 89 hours. The condensate was also separated with gel filtration chromatography and measured with a RI detector. Fourier Transform Infrared Spectroscopy was used to analyze molecules functional groups.

====Stereoselective Polymerization for a racemic monomer with a racemic catalyst Direct Production of the polylactic acid stereocomplex from racemic lactide====
http://www.cem.msu.edu/~smithmr/Publications/ja9930519.pdf Stereoselective Polymerization for a racemic monomer with a racemic catalyst Direct Production of the polylactic acid stereocomplex from racemic lactide by Radano et al uses a stereoselective catalysts to polymerize L(+)- and rac-lactide to comprehensive products tacticity. Tacticity is the stero-relation between adjacent chiral subunit (same side or different side). Tacticity has important effects on the polymers interactions and crystallinity, and Poly L(+)lactic acid has a Tm = 180 and the poly rac-lactic acid Tm is near room temperature. Tsuji et al first noted the Tm of combined stereoregular L and D polymers was raised almost 50 C. The stereoselective catalyst was a Schiff base aluminum alkoxide.

====A Highly Active Zinc Catalyst for the Controlled Polymerization of Lactide====
[http://cbs.ewha.ac.kr/pub/data/2003_04.pdf A Highly Active Zinc Catalyst for the Controlled Polymerization of Lactide] by Williams et al (2003) details a Zinc alkoxide compound paired with a ligand that has high reactivity and high molecular weight products. Zinc is an attractive catalyst due to low cost, but it has complicating aggregation behavior. Ligands help prevent this behavior and modulate desirable characteristics; the ligand (HL) used for this study was made by refluxing N,N,N′-trimethylenediamine, paraformaldehyde, and 2,4-di-tert-butylphenol. The ligand was reacted with Et2Zn to yield LEtZn which was then reacted with EtOH to produce LZnOEt the zinc alkoxide catalysts. The catalysts structure was examined in solid state (X-ray crystallography, mass spectrometry) and catalytically relevant solution state (NMR, PGSE) and was found to be dimeric in solid state and monomeric in solution state. This information allows rate equations to be solved. The PLA MW was measured with SEC-MLS and monitored with 13C NMR. The catalyst was found to be effective in L/LZnOEt ratios up to and at concentrations as low as 0.7 mM, higher than any other zinc catalysts reported. The active site is the ethoxy group and reaction is sensitive to exchange agents.

=====Sources still to be summarized=====
http://www.imm.ac.cn/journal/ccl/1208/120803-663-01061-p2.pdf

http://193.146.160.29/gtb/sod/usu/$UBUG/repositorio/10281082_Lonnberg.pdf

http://www.ch.ic.ac.uk/marshall/4I11/Coates2000.pdf

http://www.ch.ic.ac.uk/marshall/4I11/Coates2002.pdf

==Polylactic acid value adding==

=====(Poly)lactic acid: plasticization and properties of biodegrable multiphase systems=====
[http://144.206.159.178/FT/862/34291/586822.pdf (Poly)lactic acid: plasticization and properties of biodegrable multiphase systems] by Averous (2001) experimented with measuring the properties of PLA prepared with different plasticizers. Plasticizers included: glycerol, polyethylene glycol, citrate ester, PEG monolaurate, and oligomeric lactic acid. various mixtures of PLA with thermoactive starch polymers (TSP) were prepared and tested. Plasticizer treated samples show a decrease in Tg (glass transition temp) and therefore Tm (melting temp). Oligomeric lactic acid followed by low molecular weight polyethylene glycol were effective plasticizers while glycerol was ineffective. Finding effective methods to combine PLA and TSP would enhance the product.

=====Processing and Mechanical characterization of plasticized Poly lactide acid films for food packaging=====
[http://www.e-polymers.org/journal/PAT2005ePolymers/page/Oral%20Presentations/Section%20B/Martino_Ver_nica_Patricia.pro.1728860278.pdf Processing and Mechanical characterization of plasticized Poly (lactide acid) films for
food packaging] looks at the use of 4 plasticizers to increase beneficial characteristics for film.

Polylactic acid/Research Development

2015-01-06T08:11:55Z

ChuckH: /* Bacillus coagulans */

''We are like dwarfs on the shoulders of giants, so that we can see more than they, and things at a greater distance, not by virtue of any sharpness of sight on our part, or any physical distinction, but because we are carried high and raised up by their giant size.''

=Literature review=
Below is a review of peer reviewed publications and expired patents covering the areas of lactic acid from microorganisms, purification of lactic acid to polymerization grade quality, and methods of a polymerization of polylactic acid. An effort was made to reference sources that are freely available online outside of subscription databases, but in certain areas of recent progress sources requiring subscription are used. The information below informs the rationale of the proposed manufacturing protocol.

==Process Reviews==

====L (+) lactic acid fermentation and its product polymerization====
[http://www.scielo.cl/pdf/ejb/v7n2/a08.pdf L (+) lactic acid fermentation and its product polymerization] (2004) by
Narayanan et al reviews the production of lactic acid and its use as a plastic monomer. The synthetic route of lactic acid is four steps that involve fixating an activator cyanide group to an acetylaldehyde to form lactonitrile, hydrolysis of lactonitrile with sulfuric acid to yield lactic acid and ammonium salt. For purification via reactive distillation lactic acid is esterified with methanol to methyl lactate and water, methyl lactate is distilled, and hydrolyzed to lactic acid with the addition of water. The production of lactic acid from biological sources is through the fermentation of high energy carbohydrates to lactic acid by Lactic Acid Bacteria. Lactic acid is neutralized and precipitated with calcium hydroxide. Calcium lactate is collected and hydrolyzed with water. For purification lactic acid is esterified with methanol to methyl lactate and removed via distillation, before hydrolysis with water. Measurement of lactic acid can be obtained by HPLC, NAD+ colorimetric assay, or gas chromatography, in order of preferability.

Lactic acid bacteria have been extensively studied, particularly lactobacillus used in dairy preparation and lactobacillus species used for lactic acid production include ''Lactobacillus delbreuckii'' subspecies ''bulgaricus'', ''Lactobacillus helveticus'', ''Lactobacillus amylophylus'', ''Lactobacillus amylovirus'', ''Lactobacillus lactis'', ''Lactobacillus pentosus''. Rhizopus oryzae are also stereoselective LAB as well as yeasts such as'' Saccharomyces cerevisiae'' and ''Kluyveromyces lactis'' and have been investigated for their usefulness. Lactase enzymes are stereospecfic and heterolactic species have two isoforms, some species induce their second enzyme only under high concentrations of lactic acid. Certain species also contain allosterically regulated as well as unregulated isoforms. Genetic engineering on ''lactobacilli'' has shown success in controlling stereospecficity of products, reaction rate and yield; ''Rhizopus oryzae'' mutants are also under study. Favorable feedstocks are high sugar or starch plants. Nitrogen sources represent a major cost to the industry with yeast extract demonstrating superior performance to cheaper alternatives.
Techniques to increase yield include pretreatments, simultaneous saccharification, and nutrient supplementation (especially nitrogen - yeast extract).

Different bioreactor configurations have been studied and batch-wise and continuous reactor sketches are provide. Lactic acid fermentation is inhibited by increasing lactic acid concentrations and methods of filtration or pH control by alkali addition are utilized to increase yield. Methods to remove lactic acid product from the fermentation batch include ultrafiltration, ion-exchange resins, and electrodialysis. Continuous cell recycle reactors have shown high performance and utilize membranes to retain cells while removing media. Cell immobilization by biofilm establishment shows higher performance to free floating culture systems. High cell concentrations make it much more difficult to maintain optimal conditions in all parts of the reactor and can stress the cells causing stereoisomerization. Various configurations using plastic chips to increase surface area but gas exchange is a major issue. R. oryzae have a mycelium form which further complicates agitation and gas exchange.

Purification is the major challenge to lactic acid fermentation production and a variety of schemes including membrane separation, solvent extraction, and vacuum distillation. A solvent extraction using a volatile amine weak base (VAWB) is suggested by the author but consumes the volatile reagent during the purification. Table 2 contains information on the various reported polycondensation procedures. Successful polycondensation depends on the proper selection of an azeotropic solvent. Superior polymer properties are reported for ring opening polymerization including higher molecular weight by an order of magnitude, monomer conversion, linearity of product. A catalyst of f 0.05% stannous octoate is suggested. Various processes to increase the sustainability of the process has been investigated including alternatives to salt addition, intensification of membrane configuration, and selection of benign solvents.

====Polylactic acid technolgy====
[http://www.jimluntllc.com/pdfs/polylactic_acid_technology.pdf Polylactic acid technolgy] by Henton (2005) reviews production, purification, and polymerization. Discusses Cargill Dow's plant which is the largest producer at 400,000,000 lb PLA per year and produces over half the market. The plant uses continuous fermentation, preliminary lactide production followed by purification with vacuum distillation and catalytic ring opening polymerization with a tin catalyst. Purification technologies utilize a variety of characteristics of lactic acid to separate it from the broth including filtration, electrodialysis, ion exchange, distillation, liquid and solid extraction, and esterification. Tin octoate is the basis catalyst for lactide polymerization which converts LA to stereospecific form. PLA characteristics include crystallinity which affects Tg and Tm. Life cycle analysis of a accounts for the energy, wastes, and emissions produced in a process and upstream and downstream to measure the sustainable efficacy of the process.

====Development of Four Unit Processes for Biobased PLA Manufacturing====
http://www.isrn.com/journals/ps/2012/938261/ Development of Four Unit Processes for Biobased PLA Manufacturing by Chae Hwan Hong, Si Hwan Kim, Ji-Yeon Seo, and Do Suck Han (2012) obtain lactic acid from E coli and purify and polymerize polylactic acid on a pilot scale. They divide the process into four steps fermentation, separation, lactide conversion, and polymerization. Fermentation is performed by E coli KCTC 2223 on LB media in shaking flasks or a bioreactor, with fermentation pH maintained at 6.4 by addition of ammonium hydroxide. A maximum yield of approximately 50% of the input glucose at 60 g/L of D-lactic acid was obtained. Separation was performed by stacked electrodialyis to obtain concentrated ammonium lactate, followed by water splitting electrodialysis using bipolar and ion specific membranes to obtain pure lactic acid. To polymerize the lactic acid a two step process of lactide production followed by high molecular weight polymerization. Lactide formation started with removal of free water at 85°C in vacuum followed by addition of catalysts (zinc oxide or Sn(OEt)2) with a mass fraction of 1~5%. The temperature was raised to 150°C and maintained until no more water was produced, and the temperature was raised to 235 C for an hour. Zinc oxide was found to catalyze high molecular weight oligomers 7760 g/mol with a yield of 85% in a short period. A ring opening procedure started with drying the lactide at 60 C followed by catalytic polymerization with ~250 ppm tin(II)bis(2-ethylhexanoate) at 180°C and 1 hr was found produce ~150 g/mol polylactic acid.

====A Literature Review of Poly(Lactic Acid)====
[http://naldc.nal.usda.gov/download/4048/PDF A Literature Review of Poly(Lactic Acid)] (2001) by Donald Garlotta.

==Alternative routes==
Microbial is an established and viable route to lactic acid production that is an alternative to the petroleum based racemic producing process, however there are other routes using further engineered organisms or catalyzed direct reactions.

=====Engineering a Cyanobacterial Cell Factory for Production of Lactic Acid=====
[http://www.researchgate.net/publication/230620095_Engineering_a_cyanobacterial_cell_factory_for_the_production_of_lactic_acid/file/79e41502cd9dab3579.pdf Engineering a Cyanobacterial Cell Factory for Production of Lactic Acid] (2012) by S. Andreas Angermayr, Michal Paszota, and Klaas J. Hellingwerf transforms Synechocystis PCC6803 with Bacillus subtilis L-lactate dehydrogenase and transhydrogenase. Expression of the transhydrogenase is deleterious, but coexpression with dehydrogenase mediates the effect and increases lactic acid production. NADH is used as the hydrogen donor and the transhydrogenase is selected to increase the concentration relative to NADPH.

=====Catalytical conversion of carbohydrates in subcritical water: A new chemical process for lactic acid production=====
[http://144.206.159.178/FT/616/601140/12505447.pdf Catalytical conversion of carbohydrates in subcritical water: A new
chemical process for lactic acid production] investigates the effects of different salts on the conversion of hexose and triose under subcritical aqueous conditions with a focus on lactic acid production. Fructose is found to be superior to glucose with a conversion of 48%, while trioses had higher conversion rates, the highest being dihydroxyacetone with 86% (g g−1) conversion. Catalysts tested include Co(II), Ni(II), Cu(II)and Zn(II), with Zn(II) being superior and utilized as ZnSO4. Temperature, and residence time were altered in a range from 200 to 360 C and residence times from 3 to 180 s, and pressure was kept constant at 25 MPa. The experimental setup used two stainless steel reactors (tube 1: i.d. 1.0 mm, length 700 mm, volume 0.55 cm3; tube 2: i.d. 3.0 mm, length 700 mm, volume 4.95 cm3), with temperature control from a heat block and with flux being controlled by an upstream HPLC pumping in substrate. Downstream of the reactor is a heat exchanger to dissipate heat, spill valve to relieve pressure, and three way valve to direct the process stream to waste or product containers. Conversion, yield and selectivity, are calculated. Fructose can be completely degraded within 2 min at 260 C over ZnSO4 catalyst and the time further decreased with an increase in temperature, with 300 C completing conversion within 20 s. Furthermore selectivity increases from ~35% to 48% when temperature is increased from 260 C to 300 C.

==Feedstocks==
Lactic acid production by microorganisms is based on conversion of sugars to a lower energy product (lactic acid) due to an unavailability of oxygen for respiration. Feedstocks containing sugars can come from a variety of sources, but ideally it should not compete with food crops. Sources of sugar rich material that do not compete with food crops include sorghum, degraded lignocellulose, and alternative sources such as lipid extracted algal cake. Lignocellulose contains a large amount of fixed carbon and is available in large amounts as the vegetative tissue of harvested crops but is recalcitrant to degradation. A wide variety of feedstocks can be used and must be optimized to an individual situation.

===Carbohydrates crops===
=====Optimization of Lactic Acid Production from Cheap Raw Material: Sugarcane Molasses=====
[http://www.pakbs.org/pjbot/PDFs/44(1)/49.pdf Optimization of Lactic Acid Production from Cheap Raw Material: Sugarcane Molasses] (2012) by Umar Farooq, Faqir Muhammad Anjum, Tahir Zahoor, Sajjad-ur-rahman, Muhammd Atif Randhawa, Anwaar Ahmed, and Kashif Akram compared lactic acid production of lactobacillus delbrueckii using sugar cane molasses as a feedstock over a range of temperatures and feedstock concentrations. The important characteristics of a feedstock for lactic acid are low cost, minimum contaminants, rapid fermentation rate, high lactic acid production yields, little or no by-product formation and year round supply. The agricultural byproduct of sugar cane includes a molasses that contains 45-60% sugars including sucrose, glucose, and fructose. Lactobacillus delbrueckii was isolated from an indigineous yoghurt population by procedure by Harrigan (1998). Fermenation was carried out at 34ºC, 38ºC and 42ºC with 0, 6, 12, 18 and 24% substrate levels without apparent pH control for 7 days. The media contained (g 100mL-1); peptone 10.0, meat extract 10.0, yeast extract 05.0, Tween-80 01.0, K2HPO4 02.0, Sodium acetate 05.0, tri-ammonium citrate 02.0, MgSO4.7H2O 0.2, MnSO4.4H2O 0.05. Total sugars and lactic acid were measured over the experiment on a 24 hr basis. The highest temperature of 42 C was the most productive. The second highest substrates concentration, 18%, achieved the highest lactic acid concentration 11.27 g/ 100 ml, yield 85%, and productivity achieving peak sugar usage on the 3rd day.

===Lignocellulose===

=====Fermentable sugars by chemical hydrolysis of biomass=====
[http://www.pnas.org/content/107/10/4516.full Fermentable sugars by chemical hydrolysis of biomass] (2010) by Joseph B. Binder and Ronald T. Raines utilized an ionic liquid, 1-ethyl-3-methylimidazolium chloride (Emim)Cl, with an acid catalyst, HCl and H2SO4 to demonstrate efficient hexose and pentose release from cellulose and lignocellulose biomass. The process is further improved through the slow addition of water to drive the reaction toward glucose formation over degradation products despite the hydrophobicity of cellulose. The corn stover was first treated with Emim before addition of HCl and water. With the addition of water being gradually increased to 43% over 1 hour the glucose yields were increased to 90%. The hydrolysate was run over an ion-exchange column and the resulting conversion product was used as a feedstock for E coli and yeast and performed equitably with an insignificant trend towards better performance by the hydrolysate under low oxyygen conditions. The major cost of the process is in the column chromatography step. The authors speculate on better performing biocatalysts that utilize pentoses (such as Bacillus coagulans).

=====A Study of the Acid-Catalyzed Hydrolysis of Cellulose Dissolved in Ionic Liquids and the Factors Influencing the Dehydration of Glucose and the Formation of Humins=====
[http://www.cchem.berkeley.edu/atbgrp/files/ChemSusChem%202011%204%201166.pdf A Study of the Acid-Catalyzed Hydrolysis of Cellulose
Dissolved in Ionic Liquids and the Factors Influencing the Dehydration of Glucose and the Formation of Humins]

=====Hydrolysis of lignocellulosic materials for ethanol production: a review=====
[http://stl.bee.oregonstate.edu/courses/ethanol/restricted/SunCheng2002.pdf Hydrolysis of lignocellulosic materials for
ethanol production: a review] (2002) by Ye Sun, Jiayang Cheng.

====Detoxification of dilute acid hydrolysates of lignocellulose with lime====
[http://www.ncbi.nlm.nih.gov/pubmed/11312706 Detoxification of dilute acid hydrolysates of lignocellulose with lime]

===Microalgae===

=====Nannochloropsis salina biomass to lactic acid and lipid=====
[http://www.sciencedirect.com/science/article/pii/S1369703X1200191X# Nannochloropsis salina biomass to lactic acid and lipid] (paywalled) by Talukder and Wu examines the suitability of oleaginous Nannochloropsis algal cake after lipid extraction for lactic acid production by Lactobacillus pentosus.

==Lactic acid bacteria==

Choice of lactic acid producing microorganism must take into account a number of factors including productivity, stereoisomer production, feedstock flexibility, difficulty culturing - including contamination. Lactic acid production for fermentation is not an uncommon capability including human muscle tissue. A number of microorganisms with prodigious lactic acid production have been isolated and characterized and include well-known members of the lactobacillus genus such as acidophilus and delbrueckii, bacillus bacteria such as bacillus coagulans, and some fungi such as Rhizopus oryzae. Choosing an organism and strain that with high lactic acid productivity needs to consider the molecular information available on these strains as many are under intense study. Lactobacillus exist as many well established strains that are well characterized from their use in yogurt making and early adoption to the lactic acid production industry, while bacillus coagulans has recently been identified in a number of environmental isolation efforts and is now under intense study with multiple strain genomes being recently sequenced. Organisms are available with a variety of licenses from biological specimen supplier American Type Culture Collection (ATCC).

====Bacillus coagulans====
Bacillus coagulans has been an organism of recent research focus due to its possible applications in biomass conversion. To further this work genome sequencing has been performed by American and Chinese research groups e.g. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3905273/ and draft sequences have been published http://www.ncbi.nlm.nih.gov/genome/?term=CP002472 http://genome.jgi-psf.org/bacco/bacco.home.html. There is a D-LA dehydrogenase gene present that functionally expresses in E coli, but there is no detectable endogenous activity most likely due to nonexpression. B. coagulans has been isolated a number of times from the environment based on lactic acid productivity and it is under intense study for application due to its thermotolerant growth and robustness. Bacillus coagulans thermophilic nature not only removes the necessity of a sterilization of feedstock, but it overlaps with fungal lignocellulases optimal temperature and pH giving possibility to using low value lignocellulose agricultural byproducts. Bacillus coagulans is related to a well studied organism Bacillus subtilis and its molecular biology is being characterized. Plasmid transformation using electroporation has been described and vector sequences for a B coagulans/ E coli plasmid.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3165500/pdf/zjb4563.pdf
http://genome.jgi-psf.org/bacco/bacco.home.html

=====Non-Sterilized Fermentative Production of Polymer-Grade L-Lactic Acid by a Newly Isolated Thermophilic Strain Bacillus sp. 2–6=====
[http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004359 Non-Sterilized Fermentative Production of Polymer-Grade L-Lactic Acid by a Newly Isolated Thermophilic Strain Bacillus sp. 2–6] by Qin et al examines Bacillus coagulans lactic acid fermentation capacity in batch and fed-batch mode with unsterilized feedstock. The strain was newly isolated and high productivity and optical purity was achieved in both cases suggesting it may be a promising organism for lactic acid fermentation. The productivity obtained are higher than other reported strains. The report obtained 730 isolates at 55 C growth from 7 soil samples and the 2-6 strain was selected as the most productive lactic acid producer. Bacillus coagulans identity was assigned based on 16S rRNA gene sequence and an enantiomeric ratio of very high L:D enantiomers. NAD-dependent lactate dehydrogenase activity could was only detectable for the L-lactate dehydrogenase through active stained native PAGE, demonstrating enzymatic activity is entirely L-lactic specific. Initial screens utilized 97 g/L glucose and higher glucose concentrations were examined for higher productivity. Concentrations of glucose above 133 g/L were found to inhibit glucose consumption and lactic acid productivity and 97 g/L and 133 g/L glucose concentrations were used for further optimization. The nutrient requirements of the strain for nitrogen source and vitamins were investigated and the most cost effective media components of glucose 97–133, YE 12.6, soy peptide 1.2, cottonseed protein 3, NaNO3 1, NH4Cl 1, were found to produce 95% of maximum yield. Two phases of lactic acid production were identifiable in batch mode from 0-15 hour during which cell growth and lactic acid productivity were coupled and 15-30 hours when cell density reached stationary phase and lactic acid production continued to complete consumption of the glucose, albeit at a slower rate. Three fed-batch regimes were tested and the effectiveness of continuous feeding and pulse feeding were found to be superior to exponential feeding. Fed-batch experiments were conducted in 5 l and 30 l volumes with no noticeable differences in rates or products. Analysis of organic acid products using organic acid HPLC columns revealed no other detectable products. Overall, Bacillus coagulans strain sp 2-6 is a highly promising strain for the production of enantiomeric pure lactic acid in an industrial process.

=====L(+)-Lactic acid production from non-food carbohydrates by thermotolerant Bacillus coagulans=====
[http://www.springerlink.com/content/a846520t8g026738/fulltext.pdf | L(+)-Lactic acid production from non-food carbohydrates by thermotolerant Bacillus coagulans] by Ou et al examines the ability of Bacillus coagulans 36D1 to utilize carbohydrates from lignocellulosic materials treated with fungal lignocellulases. Lignocellulose materials could be a low cost source of sugars, but there are several limitations to implementation of an efficient industrial process, mainly the cost of treatment to breakdown recalcitrant lignocellulose material, complex product mixture produced by many microorganisms in industrial use, and low yield of desired products by homolactic organisms. Bacillus coagulans displays traits that may allow it to overcome these hurdles to adoption of biocatalytic lignocellulose lactic acid production. As a thermophilic organism with a growth temperature of 50-55 C and favors slightly acidic conditions lignocellases are not inhibited during simultaneous fermentation allowing a decrease in the amount of costly enzymes. Coagulans consumes the released hexoses and pentoses relieving product inhibition and creating a productive pathway. Coagulans possesses the pentose-phosphate pathway for efficient use of pentose sugars unlike other industrially known strains which possess the phosphoketolase pathway resulting in equimolar production of acetic acid and lactic acid (lowers efficiency and complicates purification). Despite its apparent advantages coagulans titer of lactic acid (depending on the strain and conditions) is often lower than is reported for other lactic acid bacteria. This study utilized salting out of the lactic acid product using calcium carbonate (CaCO3) and demonstrated titers of over 100 g/L.

=====Engineering Thermotolerant Biocatalysts for Biomass Conversion to Products=====
[http://www.osti.gov/bridge/servlets/purl/979455-cpKL66/979455.pdf Engineering Thermotolerant Biocatalysts for Biomass Conversion to Products] a technical report by K. T. Shanmugam, L. O. Ingram & J. A. Maupin-Furlow describes progress on characterizing B coagulans metabolism.

====Bacillus genetic transformation====

=====Development of plasmid vector and electroporation condition for gene transfer in sporogenic lactic acid bacterium, Bacillus coagulans=====
[http://download.bioon.com.cn/view/upload/month_0906/20090616_8a78ff4923330e867f1eOFHGOoTkD5Hq.attach.pdf Development of plasmid vector and electroporation condition for gene transfer in sporogenic lactic acid bacterium, Bacillus coagulans] (2007) by Mun Su Rhee, Jin-woo Kim, Yilei Qian, L.O. Ingram, K.T. Shanmugam contructs a plasmid Being of the same genus as the laboratory model organism Bacillus subtilis may allow the utilization of a number of laboratory plasmids to be platforms for coagulan optimization. Comparable G-C content appears to be the major limiting factor in interspecies transformation in the bacillus genus.

=====Interspecific Transformation in Bacillus=====
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC278154/pdf/jbacter00454-0221.pdf Interspecific Transformation in Bacillus]
by Julius Marmur, Edna Seaman, James Levine

Plasmid maintenance often requires continuous application of a selection pressure or else the unnecessary plasmid is jettisoned or lost during replication. Further research is needed into methods of genomic integration through homologous recombination/ strand break repair integration or protoplast transfer. Alternatively, genetic mutants with interruptions to necessary nutrient pathways can be obtained and the reintroduction of nutrient genes reintroduced as a marker.
http://www.google.com/patents?hl=en&lr=&vid=USPAT5843720&id=2eYAAAAAEBAJ

====Lactobacillus====
Lactobacillus is the lactic acid fermenator used in the production of fermented foods (from yogurt to sourdough) and has been used in the industrial fermentation of lactic acid. It produces a racemic mixture of D/L-lactic acid, but its growth characteristics are well known and its productivity is high enough to be profitable.

=====Biotechnological Production of Lactic Acid and Its Recent Applications=====
[http://www.aseanbiotechnology.info/abstract/21021670.pdf Biotechnological Production of Lactic Acid and
Its Recent Applications]

=====Optimisation of media and cultivation conditions for L(+)(S)-lactic acid production by Lactobacillus casei NRRL B-441=====
[http://download.bioon.com.cn/upload/month_0811/20081102_df48a9c25ad1c920285eJ4RBX4RJnzRY.attach.pdf Optimisation of media and cultivation conditions for L(+)(S)-lactic acid production by Lactobacillus casei NRRL B-441] (2001) by M. Hujanen, S. Linko, Y. Y. Linko, M. Leisola uses fed batch shaking flask fermentation of glucose with Lactobacillus casei using malt extract as a nitrogen source. Lactobacillus casei was chosen for its favorable sterioisomer ratio and the study aimed to optimize the fermentation process using industrially relevant growth conditions with a low cost nitrogen source. Maximum concentration obtained was 118 g/L from 160 g/L glucose and maximum productivity of 4.4 g/L/h was achieved at 100 g/L glucose at 15 hours fermentation. Malt sprout extract to glucose in a ratio of 53.8:100 was used throughout the study for a standard amount of nitrogen:carbon 22:100. Growth was conducted 1.5 l bioreactors at 35 °C, pH 6.3, 200 rpm, with pH adjustment by NaOH addition. Lactic acid and glucose were determined by HPLC using an Aminex HPX-87H+ cation-exchange column and consumption of glucose and the production of lactic acid was monitored with a YSI 2700 Select Biochemistry Analyzer. Malt sprout extract used as sole nitrogen source was found to show a loss in productivity but could be effectiviely used to supplement reduced concentration of yeast extract, down to 4 g/L. Resting fermentation was also conducted but showed a slight loss in productivity.ided by fermentation time). The maximum productivity with yeast extract was 6.0 g l at 16 h fermentation time compared to 4.9 g/l/g at 16 h by malt sprout extract and resting cells were 3.5 g/l/h.

=====Comparison of lactobacillus delbrueckii and bacillus growth and lactic acid productivity=====
[http://www.sciencedirect.com/science/article/pii/S0141022906000329# Comparison of lactobacillus delbrueckii and bacillus growth and lactic acid productivity. (paywalled)]

====Rhizopus oryzae====
=====L(+)-lactic acid production by pellet-form Rhizopus oryzae R1021 in stirred tank fermenter=====
[http://144.206.159.178/FT/158/86077/1455313.pdf L(+)-lactic acid production by pellet-form Rhizopus oryzae R1021 in stirred tank fermenter] by Bai et experimented with growth parameters effects on culture growth in a continuous run fermentor. Parameters under study included NH4NO3 concentration, CaCO3 addition timing, agitation speed and aeration rate, and inoculation concentration and effects on growth morphology and lactic acid were studied. Pellet form exhibits higher lactic acid productivities and inoculation of 10e6 spores/ml and addition of CaCO3 at 8 hours exhibited pelleted forms. Lactic acid yield was ~72.5% and with 300 rpm and aeration of 0.6 vvm yield increased to 74.5%. Biomass is limited by oxygen transfer, high biomass is necessary for high turnover of glucose to lactic acid. Biomass to lactic acid productivity was found to be highest with 2 g/l NH4NO3, 100 g/l glucose, 300-600 rpm, and 0.6-1.2 vvm. Repeated cycles using the R. oryzae culture showed sustained viability through the 7th cycle and an increase in lactic acid yield to 80%.

=====Optimization of lactic acid production with immobilized Rhizopus oryzae=====
[http://www.academicjournals.org/ajb/full%20text/2012/26Apr/Tanyildizi%20et%20al.htm Optimization of lactic acid production with immobilized Rhizopus oryzae] (2012) by Muhammet Şaban Tanyıldızı*, Şule Bulut, Veyis Selen and Dursun Özer uses polyurethane foam as a matrix and alters basic fermentation conditions.

==Lactic acid production and purification==

Early purification methods involved precipitation of a lactate salt, filtration, and hydrolysis back to lactic acid. This method had high recovery rates, but it produced large amounts salt waste (calcium sulfate) and consumed large amounts of chemical substrates (calcium hydroxide and sulfuric acid). Alternatively other salts could be used that produce a waste that is easier to handle and recover, and under consideration is the universal base sodium hydroxide.

Lactic acid cannot be easily distilled in high purity, but an ester with a small chain organic alcohol can be separated from impurities over a moderate sized distillation column. Reactive distillation of an ester of methanol and lactic acid over a 20 stage distillation column yields high purity ester that can be hydrolyzed back to the acid form. This process is capital and energy intensive, but it gains efficiency in large scale production. The process should be investigated for feasibility and efficiency on a small scale.

Lactic acid must be purified in high quality from the fermentation media in order to be suitable for polymerization. Advances in purification have involved semipermeable membrane sieves and more recently electrophoresis technology. Electrodialysis has been widely adopted for large scale organic acid production. A commercialized route of lactic acid production for polymerization from fermenation uses conventional electrodialysis to separate and concentrate the lactate salt (a basic waste stream can be recycled to the fermentor), followed by watersplitting ED with bipolar membranes to produce a highly concentrated lactic acid. Another method to eliminate the use of a pH balancing base and the production of a waste salt is size selective microfiltration, ultrafiltration and nanofiltration in a crossflow configuration.

http://www.sciencedirect.com/science/article/pii/S0960852412014460 Open fermentative production of l-lactic acid by Bacillus sp. strain NL01 using lignocellulosic hydrolyzates as low-cost raw material (paywall)

====Membrane separation====

=====Process intensiﬁcation in lactic acid production by three stage membrane integrated hybrid reactor system=====
[http://www.sciencedirect.com/science/article/pii/S0255270112002516# Process intensiﬁcation in lactic acid production by three stage membrane integrated hybrid reactor system] describes lactic acid fermention without alkali addition by the constant removal broth and separation through microfiltration and two stage nanofiltration. Innovative use of size /salt selective membranes to separate lactic acid from the fermentation broth utilizes pressure and crossflow filtration to with microfiltration and two stage nanofiltration (NF-1 and NF-2 membranes manufactured by Sepro) to produce high quality (96%) grade lacic acid. The author claims significant gains can be made in productivity and utilized a highly available feedstock of sugar cane water. The physical formulas of crossflow filtration and economic impact of widespread implementation are proposed. Membrane filtration is shown to be less energy demanding in addition to not producing significant waste. Avoiding the phase changes present in the current industrial salting out method leads to membranes significant energetic and capital cost reductions. L(+)-homolactic acid lactobacilli dulbreike is used as a biocatalyst, achieved high yields, and is available from ATCC. The fermentation broth must be sterilized before fermenation and is maintained at 40 C. Procedural techniques also are presented including: a 15 hour lag phase before fermentation broth is started through filtration, and gradual increase in up to ~16 kg/cm2 pressure driving the polishing NF-1 step over the first 12 hours as a means to reject undissociated lactate while allowing lactic acid passage. The nanofiltration stage with NF-2 membranes is conducted at 13 k/cm2. The authors convincingly argue this process intensification can be conducted on a small scale, possibly even based on solar power.

=====Process intensification in lactic acid production: A review of membrane based processes=====
[http://www.sciencedirect.com/science/article/pii/S0255270109001986 Process intensification in lactic acid production: A review of membrane based processes] (pay-walled) (2009) by Pal et al reviews membrane based separation advances in lactic acid purification. The broth contents that need to be separated are cells, nutrients, unconverted carbon, water, and lactic acid and membrane based approaches include microfiltration, ultrafiltration, nanofiltration, reverse osmosis and electrodialysis. Separation based on size from larger to smaller pore size is through microfiltration, ultrafiltration, then nanofiltration. Cells and proteins are the main causes of membrane fouling and system design needs to minimize their adsorption. Microfiltration (pores 0.1-1.2 microns) retains cells and allows other broth components to permeate. Nanofiltration (pores no larger than 0.1 nm) has been shown to be able to retain sugars while allowing lactic acid to permeate. Research has focused on coupling these two membranes to effectively separate lactic acid while allowing cell and sugar recycle in a continuous operation fermentor. Pressure is needed to drive flux, low pressure (1–2 kgf/cm2) for microfiltration, and higher pressure (6–15 kgf/cm2) for nanofiltration. PH and cross flow velocity have been identified as a key parameter for fluxes with an increase in both corresponding to an increase in flux. A variety of membrance configurations have been tested including tubular, frame and plate, and hollow fiber modules. The highest performance ultrafiltration unit reported is by Sikder et al with a laboratory-synthesized polysulfone-cellulose acetate blend microfiltration membrane in a cross flow configuration (see below: Synthesis and characterization of cellulose acetate-polysulfone blend microfiltration membrane for separation of microbial cells from lactic acid fermentation broth).

[[File:EP0393818A1_fig1.png|200px|thumb|right|General process overview]][[File:EP0393818A1_fig2.png|200px|thumb|right|Detailed view of electrodialysis configuration]]
=====Production and purification of lactic acid=====
[http://www.freepatentsonline.com/EP0393818.pdf Production and purification of lactic acid] European Patent EP0393818A1 issued to Glassner and Datta of the Michigan Biotechnology Institute on October 24 1990 details a commercialized route of lactic acid production from fermentation bacteria. The process uses Lactobacillus acidophilus (ATCC 53681 which cannot be located in the [http://www.atcc.org/ ATCC catalog] fed with corn steep liquor and corn oil and reports yields of 80% of the theoretical maximum, with low contamination in the order of less than 1% protein and 10 ppm sulfate ions. The process adds a salt to form lactate complexes which is processed with conventional electrodialysis to create a cell free concentrated lactate salt stream and a dilute broth which is returned to the fermentation chamber. The lactate stream is concentrated through evaporation and processed to a relatively concentrated and purified fraction using water splitting electrodialysis. Strong acid followed by weak base ion-exchange columns are used for polishing to create a purified product of polymerization grade. The process was tested on small 1-2 l, pilot 80 l, and large 500 l scales and productivity and efficiency remained constant as correlated to substrate density and cell density (margin between cell growth versus LA production). The process was tested with continuous batch and cell recycle fermentation. The process is reported to have several advantages including high productivities and recovery rates, low energy requirements (~0.5 kwhr/ lb LA), the possible reuse of salt anion and cation after recovery from the electrodialysis unit, and the dual use of electrodialysis to separate cells from whole broth for recycle without compromising the purity or efficiency of the electrodialysis step.
The process details are as follows. A fermentation media containing 1.0-4.0% steep corn liquor and 0.1-1.0% crude corn oil were combined in water, the concentration of carbohydrates is 20-120 g/l and preferably 40-100 g/l. the media is sterilized and inoculated with 5% inoculum. Growth conditions are maintained with agitation at 75 rpm and a temperature between 20-50 C, and preferably 39 C. The media pH is maintained between 4.8 and 5.7 through the addition of carbonates or hydroxides, preferably sodium or ammonium hydroxide. At a cell concentration of 2.5E10-3.0E10 high lactate productivities can be maintained in the order of 2.0-2.5 g/l/hr with a product concentration of approximately 75-90 g/l. Continuous culture fermentation was conducted in seal flasks using a peristaltic pump to remove broth and additions of an equal volume of fresh broth and salts. A cell recycle fermentor consisted of a growth chamber, a 0.2 micron ultra-filtration unit that returned cells to the chamber, and an effluent capturing container. Whole broth was filtered through 200 mesh to remove debris before direct addition to the electrodialysis chamber.
The conventional electrodialysis unit consists of 8 stacks of anion and cation permeable membranes with a total surface area of 102.4 cm2. The electrolyte used was 2.5 M NaOH. A representative configuration is displayed in figure 2, however adaptions may be made by the user. The configuration displayed contains distribution flow gaskets (18), anion permeable membranes (19), cation permeable membranes (20), parallel cells (21) consisting of 18+19+20, and end cells (22 and 23) consisting of 19+20+ end caps (24). End cell 22 is connected to the cathode (25) via the a connector (27), and end cell 23 is connected to the anode (26) through a connector (28), both end cells are connected to a rinse system that circulates a electrolyte solution (such as NaSO4 or lactate salt). Fermentation broth is passed through a screen (13) and passed to the electrodialysis unit via line 14, basic solutes are passed through the parallel cells and returned to the fermentor through a continuation of line 14. Line 15 circulates a lactate salt solution in the parallel cells and lactate from the broth is concentrated through the anion permeable membranes (19) and collected on the effluent side of the system. The collected effluent is further concentrated via evaporation.

=====Process development and optimisation of lactic acid puriﬁcation using electrodialysis=====
[http://144.206.159.178/FT/549/63720/1083859.pdf Process development and optimisation of lactic acid
puriﬁcation using electrodialysi] by Madzingaidzo et al examines purification of lactic acid from fermentation broth using mono and bi-polar electrodialysis. A mono-polar membrane selectively allows cations or anions to traverse the layer, while a bi-polar layer is made of a cation and anion membrane that splits water molecules into H+ and OH- for charge balancing. An electrical current is applied to the dialysis chamber to separate molecules according to their charge and mono and bi-layer membranes create channels concentrated with certain components. In mono-layer electrodialysis a alternating semipermeable membranes starting with a cation membrane next to the anode (+), a dilute stream feeds through center from which lactic acid is concentrated through a anion exchange membrane towards the anode. Charge is balanced from an electrode rinse solution that circulates next to the electrodes. A bi-polar uses bi-polar membranes to separate the electrode rinse solution from the concentrating channels creating sections holding a base, salt and final acid form. A measurement of % current efficiency (current used to transport molecule from input to concentrated stream/ total current) is used to evaluate the process.

*Reverse osmosis

=====Sources still to be summarized=====
[http://www.sciencedirect.com/science/article/pii/S0011916409008996 Synthesis and characterization of cellulose acetate-polysulfone blend microfiltration membrane for separation of microbial cells from lactic acid fermentation broth] (paywalled)

[http://144.206.159.178/FT/986/206651/5195502.pdf] An electrokinetic bioreactor: using direct electric current for
enhanced lactic acid fermentation and product recovery

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC203522/pdf/aem00131-0098.pdf Novel Method of Lactic Acid Production by Electrodialysis Fermentation

[http://oatao.univ-toulouse.fr/2918/1/Bouchoux_2918.pdf http://oatao.univ-toulouse.fr/2918/1/Bouchoux_2918.pdf]

http://www.sciencedirect.com/science/article/pii/S0011916411010290# Separation of lactic acid from fermentation broth by cross flow nanofiltration: Membrane characterization and transport modelling (paywall)

http://link.springer.com/article/10.1007%2Fs10098-011-0448-z?LI=true (paywall)

====Reactive Distillation====

=====Lactic acid purification=====
[[File:US2350370.png | 200 px | thumb | Right | US patent 2,350,370 ]]
[http://www.google.com/patents/US2350370 Lactic acid purification] issued to Schopmeyer June 6 1944 covers a method to purify lactic acid from fermentation broth by the use of calcium carbonate salts and esterification with methanol for fractional distillation. The fractional distillation set-up includes a boiler containing methanol and lactic acid and a catalyst (H2SO4) that delivers vapors to a fractionation column that allows the separation of a concentrated lactic acid liquor of ~10-50%. The salting out of calcium lactate uses calcium sulfate which is concentrated and converted to acid form through treatment with sulfuric acid, calcium sulfate forms an insoluble fraction. The concentration was usually 40-60% lactic acid and ethanol can also be used as the esterification. The esterification procedure uses a steam jacket with the following substrate mole ratio 1.5:1:0.005 methyl alcohol: lactic acid: sulfuric acid. Start-up of purification uses 80% lactic acid substrate (depending on concentration), 20 methanol, and a small amount of catalyst. Steady-state is maintained by addition of substrates and catalyst, and recycling of methanol.

=====Optimization of Batch Reactive Distillation Process: Production of Lactic Acid=====
[http://www.aidic.it/escape20/webpapers/34Edreder.pdf Optimization of Batch Reactive Distillation Process: Production of Lactic Acid] by Edreder (2010) develops a model for esterifying lactic acid with methanol and distills the methyl lactate, the lactic acid is recovered by hydrolysis. The purity analyzed was 80-99% molefraction, it took 4 refluxes to theretically reach the highest purity.

=====Recovery of lactate esters and lactic acid from fermentation broth=====
[http://www.google.com/patents/US5210296 Recovery of lactate esters and lactic acid from fermentation broth]
issued to Cockrem et al details a method for continuous recovery of lactic acid from fermentation broth using reactive distillation with an alcohol.

====Solvent Extraction====

http://www.google.com/patents/US4771001 Production of lactic acid by continuous fermentation using an inexpensive raw material and simplified form of purification issued to Bailey et al on September 13 1988 deals with a method for production of lactic acid from a the raw sugar source whey permeate and purification solvent extraion. The operational advantage of such a system is the high cell densities that can be achieved and maintained however this raises the challenges of preventing fouling particularly for membrane based cell recycling.

==Polylactic acid polymerization==

====Melt–solid polycondensation of lactic acid and its biodegradability====
[http://www.sciencedirect.com/science/article/pii/S007967000800097X Melt–solid polycondensation of lactic acid and its biodegradability] T. Maharanaa, B. Mohantyb, Y.S. Negi examines the developments in polycondensation formation of PLLA with a set of 4 catalysts. With a decade of research into the technique the reaction dynamics and structure of different stereoisomers has been examined by many investigators. The polycondensation polymerization routes is being investigated for its lower cost and capital investment over the ring opening procedure despite initially producing a polymer of less desirable parameters, such as high melt viscocity, discolorization, and difficulty achieving high molecular weight products. Tin oxide formed from tin chloride with a protonic acid (such as p-toluenesulfonic acid - TSA) is a potent catalyst that can be used in such low concentrations that purification isn't necessary. The polymerization mechanism model originally proposed by Moon involve the coordination of terminal carboxyl condensation with the hydroxyl group on the center carbon. TSA may not be catalytically involved in the reaction, but it may occupy a tin catalytic site to increase the favorability of the desired reaction over side reactions. The reaction can achieve high molecular weight PLLA (ca. 105 Da) by the catalysis of tin(II) chloride dihydrate with an equimolar amount of TSA within 35 h under 0.13–2.66 kPa pressure and within a temperature range of 180–200 C with an average yield of 67%. TSA evaporates during the process and a second addition can further assist the reaction. Solid state polymerization uses temperatures above Tg, but below Tm and sometimes plasticizers to increase terminal end mobility (reaction substrate) to form PLA of high MW with desirable properties.

====Syntheis and Properties of High Molecular Weight Poly(Lactic Acid) and its resulting fibers====
[http://www.cjps.org/EN/article/downloadArticleFile.do?attachType=PDF&id=11239 Syntheis and Properties of High Molecular Weight Poly(Lactic Acid) and its resulting fibers] by Zhang and Wang tests the polylactic acid polymerization melt/solid polycondensation process with a number of catalysts. The now commercial route uses a first step of azeotropic dehydration with reflux, in a high boiling point, aprotic solvent like diphenyl ether to produce 50 kDa polymers. The second step joins these fibers with reduced pressure and a tin and protic acid catalyst. This study uses SnCl2·2H2O/p-toulenesulfonic acid monohydrate (TSA) and SnCl2·2H2O/maleic anhydride catalyst for the first step and TSA in the second step. This improves upon Moon et al. with the addition of TSA in the second step because the environmental polarity was found to be shifted in the first step. Polymer MW had leveled off in step 1, but it continued in step 2 with the addition of more catalyst (TSA). SnCl2·2H2O/maleic anhydride was found to be a more effective catalyst due to the less crystalline nature which allowed further polymerization in the amorphous regions. An increase in reaction temperature for the second step was found to be effective up to 180 C and degradative at higher temperatures. The process starts by combining 400 g distilled lactic acid is with the designated catalyst (0.5% wt SnCl2·2H2O and 0.4% wt TSA or maleic or succinic anhydride)and sealed in the reactor. The reaction is heated to 150 C 4 hrs , the reaction is then heated to 160 C and the pressure reduced to 500 Pa for 4 hrs. After an initial low-weight polymerization the reflux condenser is removed and 0.4% wt (of starting lactic acid) TSA is added to the reactor. The temperature is further increased to 180 C and the pressure reduced to 300 Pa for 10 hrs. The polymerization product was dried and processed used standard melt spinning procedures before a final draw between 150-200 C under nitrogen. The final fiber product was characterized with FTIR, DSC, an Ubbelohde viscosimeter, and tensile-testing machine. Final spinning produced a fiber made of high molecular weight polymers and has high tensile strength.

====Melt/solid polycondensation of l-lactic acid: an alternative route to poly(l-lactic acid) with high molecular weight====
[http://144.206.159.178/FT/862/34857/596552.pdf Melt/solid polycondensation of l-lactic acid: an alternative route to
poly(l-lactic acid) with high molecular weight] by Moon et al (2000) describes a method that yields high weight PLA on the order of 500,000 daltons through a condensation reaction using a tin chloride dihydrate/p-toluenesulfonic acid binary system. They report that reaction temperatures below the Tm (melting point) of PLA yields a better product and is referred to as melt/solid polycondensation. oligo(l-lactic acid) (OLLA) is mixed with tin(II) chloride dihydrate (SnCl2) (0.4 wt% relative to OLLA) and p-toluenesulfonic acid (TSA) (an equimolar ratio to SnCl2). The mixture is heated to 180 C and the pressure reduced to 10 torres over the period of an hour followed by maintenance for 5 hrs. The product consisting of 20,000 dalton polymers is ground and heated to 105 C under vacuum for 1-2 hr to crystallize the polymers. Solid-state post-polycondensation was initiated by increasing the temperature to 150 C and reducing the pressure to 0.5 Torr. Treatment was continued over 30 hours, but molecular weight peaked between 2-10 hours and drastically reduced after 20 hours. The results showed a method to obtain high molecular weight PLLA with comparable characteristics to the lactide ROP synthesis. The method used here catalyzes the first step of dehydration to form lactide and the lactide ROP step follows. The high activity of the catalyst and the ability to move through the amorphous PLLA may be driving the reaction by concentrating ester tails and catalyst in the amorphous regions during crystallization.

====Basic properties for film polylactic acid produced direct condensation polymerization of lactic acid====
[http://www.csj.jp/journals/bcsj/J-STAGE/6808/pdf/68_2125.pdf Basic properties for film polylactic acid produced direct condensation polymerization of lactic acid] by Ajioka characterizes the polylactic acid products of different catalysts and solvents under 130-250 C. Polymerization was commercially pursued from an isolated dilactide intermediate, but direct polymerization is possible due to improvements in kinetic control, removal of resulting water, and suppression of depolymerization. Solvents controlled the rate of reaction based upon their boiling point and the ability to remove water and a Dean Stark trap used, diphenyl ether results shown. Tin and protonic acids catalysts were found to have superior performance with tin(II) chloride achieving highest efficiency and high molecular weights. Zinc catalysts produced maximum 150 kDa weight polymers at 160 C. Weights and flow rates comparable to dilactide process and usable for injection molding. D and L enantiomers were polymerized in ratios of 50/50 to 0/100 respectively. Pure L form had the highest strength and molecular weight. 13C NMR of direct condensation PLA showed 5 carbonyl signals, an additional lower signal from adjacent L subunits. <br />
Direct synthesis of PLA general protocol <br />
In a reaction chamber with a Dean Stark trap 40.2 g 90% lactic acid and 0.14 g tin were dissolved in 400 ml organic solvent for 2 hr at 140 C. The trap was replaced with a tube containing 40 g molecular sieve (3 A) for azeotropic separation for 20 to 40 hr at 130 C. At half volume 300 ml chloroform was added and catalyst removed with filtration or extraction. PLA product was by precipitation by 900 ml methanol and washing over suction with methanol. <br />
Cyclic oligomer production <br />
10.0 kg of 90% lactic acid azeotropically dried 81.1 kg diphenyl-ether organic solvent with 6.2 kg tin catalyst at 150 C for 2 hr. This was followed by recycling of solvent using 4.6 kg molecular sieve (3 A) for 40 hr at 140 C. The reaction was concentrated to 70 kg, cooled to 40 C, and PLA crystals collected. The reaction was concentrated to 5.8 kg. A 11.6 kg hexane was added to the filtrate and an oil separated with 5.8 kg acetonitrile and 1 M HCl. An oily substance was collected after 30 min of agitation and washed with 5.8 kg water. The washed product was dissolved in 2.9 kg chloroform and combined with 4 l isopropyl alcohol and a final precipitated product collected over suction and dried with reduced pressure. Final yield 350 g.

====Synthesis of polylactic acid by direct polycondensation under vacuum without catalysts, solvents and initiators====
Synthesis of polylactic acid by direct polycondensation under vacuum without catalysts, solvents and initiators by Achmad et al details a procedure. The authors recommend PLA be pursued using processing plants capable of fermenting feedstock, purifying lactic acid, and condensing the product as is proposed for the OSE product ecology. Streptococcus bovis is a LAB suggested for use, but the species is also linked to pathogenicity. The process used by the researchers used three phases for treating the lactic acid and polymerizing its monomer: distillation, oligomerization, and polymerization. The reaction was carried out in 4 l sealable flasks, on magnetic stirrers and heaters, with temperature and pressure probes, and connected to a pressure regulator. During distillation sample temperature is brought to 150 C over 90 minutes and maintained for 60 minutes and PLA concentration increases from 90% to 100% as measured by acid-base titrations. Oligomerization phase was a reduction in pressure to 10 mmHg and temperature was raised to 200 C. The polymerization step was maintenance of the reduced pressure and temperature for 89 hours. The condensate was also separated with gel filtration chromatography and measured with a RI detector. Fourier Transform Infrared Spectroscopy was used to analyze molecules functional groups.

====Stereoselective Polymerization for a racemic monomer with a racemic catalyst Direct Production of the polylactic acid stereocomplex from racemic lactide====
http://www.cem.msu.edu/~smithmr/Publications/ja9930519.pdf Stereoselective Polymerization for a racemic monomer with a racemic catalyst Direct Production of the polylactic acid stereocomplex from racemic lactide by Radano et al uses a stereoselective catalysts to polymerize L(+)- and rac-lactide to comprehensive products tacticity. Tacticity is the stero-relation between adjacent chiral subunit (same side or different side). Tacticity has important effects on the polymers interactions and crystallinity, and Poly L(+)lactic acid has a Tm = 180 and the poly rac-lactic acid Tm is near room temperature. Tsuji et al first noted the Tm of combined stereoregular L and D polymers was raised almost 50 C. The stereoselective catalyst was a Schiff base aluminum alkoxide.

====A Highly Active Zinc Catalyst for the Controlled Polymerization of Lactide====
[http://cbs.ewha.ac.kr/pub/data/2003_04.pdf A Highly Active Zinc Catalyst for the Controlled Polymerization of Lactide] by Williams et al (2003) details a Zinc alkoxide compound paired with a ligand that has high reactivity and high molecular weight products. Zinc is an attractive catalyst due to low cost, but it has complicating aggregation behavior. Ligands help prevent this behavior and modulate desirable characteristics; the ligand (HL) used for this study was made by refluxing N,N,N′-trimethylenediamine, paraformaldehyde, and 2,4-di-tert-butylphenol. The ligand was reacted with Et2Zn to yield LEtZn which was then reacted with EtOH to produce LZnOEt the zinc alkoxide catalysts. The catalysts structure was examined in solid state (X-ray crystallography, mass spectrometry) and catalytically relevant solution state (NMR, PGSE) and was found to be dimeric in solid state and monomeric in solution state. This information allows rate equations to be solved. The PLA MW was measured with SEC-MLS and monitored with 13C NMR. The catalyst was found to be effective in L/LZnOEt ratios up to and at concentrations as low as 0.7 mM, higher than any other zinc catalysts reported. The active site is the ethoxy group and reaction is sensitive to exchange agents.

=====Sources still to be summarized=====
http://www.imm.ac.cn/journal/ccl/1208/120803-663-01061-p2.pdf

http://193.146.160.29/gtb/sod/usu/$UBUG/repositorio/10281082_Lonnberg.pdf

http://www.ch.ic.ac.uk/marshall/4I11/Coates2000.pdf

http://www.ch.ic.ac.uk/marshall/4I11/Coates2002.pdf

==Polylactic acid value adding==

=====(Poly)lactic acid: plasticization and properties of biodegrable multiphase systems=====
[http://144.206.159.178/FT/862/34291/586822.pdf (Poly)lactic acid: plasticization and properties of biodegrable multiphase systems] by Averous (2001) experimented with measuring the properties of PLA prepared with different plasticizers. Plasticizers included: glycerol, polyethylene glycol, citrate ester, PEG monolaurate, and oligomeric lactic acid. various mixtures of PLA with thermoactive starch polymers (TSP) were prepared and tested. Plasticizer treated samples show a decrease in Tg (glass transition temp) and therefore Tm (melting temp). Oligomeric lactic acid followed by low molecular weight polyethylene glycol were effective plasticizers while glycerol was ineffective. Finding effective methods to combine PLA and TSP would enhance the product.

=====Processing and Mechanical characterization of plasticized Poly lactide acid films for food packaging=====
[http://www.e-polymers.org/journal/PAT2005ePolymers/page/Oral%20Presentations/Section%20B/Martino_Ver_nica_Patricia.pro.1728860278.pdf Processing and Mechanical characterization of plasticized Poly (lactide acid) films for
food packaging] looks at the use of 4 plasticizers to increase beneficial characteristics for film.

Stationary Hydraulic Power

2014-12-26T09:47:15Z

ChuckH: /* Small storage */

= Introduction =
A stationary hydraulic power installation is similar to a "shop air" compressed air system. Typically a central power unit (pump) provides pressurized hydraulic fluid to a plumbing system, which distributes it to multiple points of access around a machinery installation or a building. In the early 20th century municipal hydraulic power flourished [http://www.subbrit.org.uk/sb-sites/sites/h/hydraulic_power_in_london/index.shtml in London], and dockyards often had substantial stationary hydraulic installations. While this type of installation is relatively uncommon in current practice, it has potential advantages in the [[GVCS]] ecosystem. This page is an exploration of stationary hydraulic power implementation issues.

[[File:PWM_generator.png|thumb|Hydraulically driven electrical generator with PWM speed regulation]]
Benefits
* High peak-to-average-power loads are easily handled
* Hydraulic energy can be efficiently stored for load leveling
* The same hydraulic-powered tool with quick-connect hose fittings can be used
** in the shop,
** in a remote location with a [[Powercube]], or
** as an accessory to the [[LifeTrac]].
* Shop tools benefit from the high power density of hydraulic actuators

It is also fairly simple and efficient to drive an electrical generator from a hydraulic motor, possibly with a switch-mode hydraulic control for speed regulation. See also [[Steam_Hydraulic_Hybrid_Electrical_Generator |Steam-Hydraulic Electrical Generator]]

= Design Principles =

== Constant Pressure ==
In contrast to simple mobile hydraulics (like the [[Initial_LifeTrac_design#OSTrac_Hydraulic_System |LifeTrac design]]), a stationary hydraulic power system must support a number of independent tools which can be running simultaneously (e.g. used by different people) without interfering with each other. This requires a ''constant-pressure, variable flow'' system, rather than the ''constant flow'' approach which is common in small mobile machinery.

== Constant-Pressure pump systems ==
The most common industrial approach to making a constant-pressure hydraulic power unit is to employ a variable-displacement pump driven by a constant-speed electric motor. Vane pumps, and axial piston pumps (with adjustable swash plates), are popular designs. However, alternative approaches are possible, including
* fixed-displacement gear pump on a variable-speed motor
* cyclic (on/off) pump action charging a pressure reservoir ("[http://en.wikipedia.org/wiki/Hydraulic_accumulator hydraulic accumulator]")
** this is similar to an air compressor cycling on and off to keep a shop air tank up to pressure
** a continuously-running gear pump may be intermittently connected to the accumulator, through an automatic valve under pressure-sensor control (this is similar to an "unloader" valve commonly used on large shop air compressors). A standard [[Powercube]] can be connected in this mode.
* A [[Steam_Engine |steam engine]] with variable valve timing can adapt its output speed and power dynamically to a varying hydraulic system load.
** A [[Steam_Engine_Design/Suggestions#Crankless_.28Free_Piston.29_Hydraulic |free-piston]] engine is particularly appropriate here

== Hydraulic Accumulator Function ==

A hydraulic accumulator is an energy storage device. Several styles of operation are possible, depending on the amount of stored energy (which may be expressed as the number of minutes of operating load contained in the accumulator).
* Large storage (hours of operation)
* Small storage (minutes of operation)
* Pulse absorption (seconds or less)

=== Large storage ===
Large storage applications may be compared to the battery banks used in solar electric systems, which carry the operational load when the sun is unavailable.

[[File:Bristolaccumulator.JPG|thumbnail|Raised-weight accumulator at Bristol Harbor, England]]
Hydraulic accumulators have ''much'' lower energy density than electrochemical batteries, so a huge device is needed. Historically, the most practical devices for this purpose have been raised-weights, which are a very simple technology. Compared with batteries, this can also be quite efficient: there is effectively zero self-discharge loss, and charge/discharge losses are limited to seal friction in the lifting cylinder. Operating at a 20-ft lift, a raised weight stores 2 horsepower-hour per 100 tons; a 100-ton cube of concrete is about 11 feet on a side. (The same 2 hp-hr could be stored in about 100 lb of lead-acid storage batteries).

Early stationary hydraulic systems most commonly operated with water at around 50 atmospheres (700 psi), a pressure range similar to modern oil-hydraulic passenger elevators. Elevator cylinders ("[http://eeco-elevatorcomponents.com/Jacks.html jacks]") are commonly made up to 50 ft or so in length. For the GVCS ecology, it would be desirable to operate at a higher system pressure, perhaps 2000psi.

A raised-weight accumulator can be supported on several small-diameter cylinders with an aggregate piston area adequate to support the weight at nominal system pressure. This type of design is quite modular, as capacity can be added
* by fitting more cylinders and adding proportionately more material to the weight
* by stacking cylinders in series (increase the lifting distance)
* by connecting additional modular accumulator capacity -- simply a cylinder and weight -- at any location in the hydraulic distribution system.

As with any installation capable of storing considerable energy, the potential for dangerous accident should be considered. The collapse of a raised-weight structure is a relatively benign failure, compared to a compressed-gas explosion, for example.

=== Small storage ===

Small storage applications apply to systems where prime-mover capacity (e.g. a steam or internal-combustion engine) is available to carry an intermittent operational load, but takes some time to start and come on line. In this situation, the accumulator serves the function of [http://en.wikipedia.org/wiki/Operating_reserve spinning reserve] of electrical utilities. Small storage accumulators are also very important in the very common situation where the prime mover does not have the capacity to handle peak load but can support the average load.

High peak-to-average loads arise both directly (e.g. CEB, drill press) and indirectly (e.g. hydraulically-driven electrical generator powering an arc welder).

In a small-scale installation, the hydraulic system is often completely idle. When the system is in "standby" (nobody is using hydraulic power at the moment), the lines remain pressurized. If there is no major leakage, the main pump can be turned off and the accumulator will maintain pressure. When a tool is connected and fluid begins to flow, the pump will turn on. A small-storage accumulator can seamlessly provide hydraulic power while the pump starts up. The pump turn-on can be triggered by a pressure drop or by an accumulator-capacity sensor.

For these applications gas-bladder accumulators are at least as suitable as raised weights. The compressed-air/hydraulic [http://fluidpowerjournal.com/wp-content/uploads/2012/12/FPJTD09_CC.pdf "open accumulator"] achieves much higher energy density than a gas bladder with a tradeoff in increased complexity.

=== Pulse absorption ===

Hydraulic shock and surge loads arise from valves that open or close quickly or actual mechanical shocks that are part of the tool operation. It is helpful to isolate the main distribution system from these shocks, which can cause momentary peaks or dips in pressure to other tools, higher frictional flow losses, and extra stress on the distribution piping. Small gas-bladder accumulators located close to the tool (either incorporated at the tool itself, or at the quick-connect outlet it is fed from) serve this need.

== Constant-Pressure Tools ==
For use on a constant-pressure shop supply, a tool's flow path should be ''blocked'' (no flow) when it is not in use. In contrast, on a constant-flow mobile system, a subsystem's flow path is ''open'', through the "power beyond" valve gallery to tank return, when it is not in use. This is a concern for tools which incorporate their own valving; for example, it may be necessary to make a porting change in order to connect a [[CEB Press]] to the constant-pressure shop supply line. On the other hand, a simple actuator which connects to the LifeTrac hydraulic takeoff (and expects to be controlled by the LifeTrac HTO control valve) will operate equally well from an appropriate "shop" control valve connected for constant-pressure supply.

== Hydraulic pressure transformation ==

In most multi-circuit hydraulic applications, efficiency is poor because the operational cycle requires the load pressure and load flow to vary widely, but the prime mover/pump can only be optimized for a single pressure/flow operating point. Efficiency is improved with load-adaptive pumps (variable displacement, load sensing circuits). However this technique optimizes dynamically to a single circuit's load and does not scale to many circuits driven by a single pump -- the situation in a constant-pressure stationary hydraulic power distribution system.

[[File:PWM_flowcontrol.png|thumb|240px|PWM transformer to drive constant-flow load from constant-pressure system]][[File:LinyiGuTransformer.png|thumb|240px|Using two valves, this design dynamically transforms to either higher-pressure/lower-flow ''or'' lower-pressure/higher-flow]]
[[File:IHTfloatingCup.png|thumb|240px|Hydraulic transformer "floating cup" design from Innas BV]]
Efficiency and other benefits accrue with the availability of "hydraulic transformers" which convert input hydraulic power at one pressure/flow level to hydraulic output power at a different pressure/flow level; this is most useful when the transformation ratio is dynamically adjustable. Four approaches are:
* piston intensifier (fixed transformation ratio): pressure applied to a large-area piston pumps fluid from a small-area piston, typically using a "stepped" piston with two different diameters.
* pump intensifier (fixed transformation ratio): a fixed-displacement hydraulic motor drives a fixed displacement hydraulic pump where there is either a different displacement per revolution or a mechanical gear ratio between the motor and pump
* "reverse hydrostatic drive": a hydraulic motor drives a variable-displacement hydraulic pump.
* [http://www.innas.com/IHT.html this] proprietary hydraulic transformer made by Innas
* [http://www.me.umn.edu/~pli/papers/RannowIMECE2006.pdf switch-mode] hydraulic transformer like this from Cao et al [http://dx.doi.org/10.1115/IMECE2006-13453 ], [http://sklofp.zju.edu.cn/lygu/SMHPS.ppt] in China
Note that the last two approaches are relatively new (less than a decade old).

A switch-mode hydraulic transformer may be an effective way to operate constant-flow ("open-center"-design) tools from a constant-pressure stationary hydraulic power system.
[[Category:Hydraulics]]

Stationary Hydraulic Power

2014-12-26T09:43:49Z

ChuckH: /* Small storage */

= Introduction =
A stationary hydraulic power installation is similar to a "shop air" compressed air system. Typically a central power unit (pump) provides pressurized hydraulic fluid to a plumbing system, which distributes it to multiple points of access around a machinery installation or a building. In the early 20th century municipal hydraulic power flourished [http://www.subbrit.org.uk/sb-sites/sites/h/hydraulic_power_in_london/index.shtml in London], and dockyards often had substantial stationary hydraulic installations. While this type of installation is relatively uncommon in current practice, it has potential advantages in the [[GVCS]] ecosystem. This page is an exploration of stationary hydraulic power implementation issues.

[[File:PWM_generator.png|thumb|Hydraulically driven electrical generator with PWM speed regulation]]
Benefits
* High peak-to-average-power loads are easily handled
* Hydraulic energy can be efficiently stored for load leveling
* The same hydraulic-powered tool with quick-connect hose fittings can be used
** in the shop,
** in a remote location with a [[Powercube]], or
** as an accessory to the [[LifeTrac]].
* Shop tools benefit from the high power density of hydraulic actuators

It is also fairly simple and efficient to drive an electrical generator from a hydraulic motor, possibly with a switch-mode hydraulic control for speed regulation. See also [[Steam_Hydraulic_Hybrid_Electrical_Generator |Steam-Hydraulic Electrical Generator]]

= Design Principles =

== Constant Pressure ==
In contrast to simple mobile hydraulics (like the [[Initial_LifeTrac_design#OSTrac_Hydraulic_System |LifeTrac design]]), a stationary hydraulic power system must support a number of independent tools which can be running simultaneously (e.g. used by different people) without interfering with each other. This requires a ''constant-pressure, variable flow'' system, rather than the ''constant flow'' approach which is common in small mobile machinery.

== Constant-Pressure pump systems ==
The most common industrial approach to making a constant-pressure hydraulic power unit is to employ a variable-displacement pump driven by a constant-speed electric motor. Vane pumps, and axial piston pumps (with adjustable swash plates), are popular designs. However, alternative approaches are possible, including
* fixed-displacement gear pump on a variable-speed motor
* cyclic (on/off) pump action charging a pressure reservoir ("[http://en.wikipedia.org/wiki/Hydraulic_accumulator hydraulic accumulator]")
** this is similar to an air compressor cycling on and off to keep a shop air tank up to pressure
** a continuously-running gear pump may be intermittently connected to the accumulator, through an automatic valve under pressure-sensor control (this is similar to an "unloader" valve commonly used on large shop air compressors). A standard [[Powercube]] can be connected in this mode.
* A [[Steam_Engine |steam engine]] with variable valve timing can adapt its output speed and power dynamically to a varying hydraulic system load.
** A [[Steam_Engine_Design/Suggestions#Crankless_.28Free_Piston.29_Hydraulic |free-piston]] engine is particularly appropriate here

== Hydraulic Accumulator Function ==

A hydraulic accumulator is an energy storage device. Several styles of operation are possible, depending on the amount of stored energy (which may be expressed as the number of minutes of operating load contained in the accumulator).
* Large storage (hours of operation)
* Small storage (minutes of operation)
* Pulse absorption (seconds or less)

=== Large storage ===
Large storage applications may be compared to the battery banks used in solar electric systems, which carry the operational load when the sun is unavailable.

[[File:Bristolaccumulator.JPG|thumbnail|Raised-weight accumulator at Bristol Harbor, England]]
Hydraulic accumulators have ''much'' lower energy density than electrochemical batteries, so a huge device is needed. Historically, the most practical devices for this purpose have been raised-weights, which are a very simple technology. Compared with batteries, this can also be quite efficient: there is effectively zero self-discharge loss, and charge/discharge losses are limited to seal friction in the lifting cylinder. Operating at a 20-ft lift, a raised weight stores 2 horsepower-hour per 100 tons; a 100-ton cube of concrete is about 11 feet on a side. (The same 2 hp-hr could be stored in about 100 lb of lead-acid storage batteries).

Early stationary hydraulic systems most commonly operated with water at around 50 atmospheres (700 psi), a pressure range similar to modern oil-hydraulic passenger elevators. Elevator cylinders ("[http://eeco-elevatorcomponents.com/Jacks.html jacks]") are commonly made up to 50 ft or so in length. For the GVCS ecology, it would be desirable to operate at a higher system pressure, perhaps 2000psi.

A raised-weight accumulator can be supported on several small-diameter cylinders with an aggregate piston area adequate to support the weight at nominal system pressure. This type of design is quite modular, as capacity can be added
* by fitting more cylinders and adding proportionately more material to the weight
* by stacking cylinders in series (increase the lifting distance)
* by connecting additional modular accumulator capacity -- simply a cylinder and weight -- at any location in the hydraulic distribution system.

As with any installation capable of storing considerable energy, the potential for dangerous accident should be considered. The collapse of a raised-weight structure is a relatively benign failure, compared to a compressed-gas explosion, for example.

=== Small storage ===

Small storage applications apply to systems where prime-mover capacity (e.g. a steam or internal-combustion engine) is available to carry an intermittent operational load, but takes some time to start and come on line. In this situation, the accumulator serves the function of [http://en.wikipedia.org/wiki/Operating_reserve spinning reserve] of electrical utilities. Small storage accumulators are also very important in the very common situation where the prime mover does not have the capacity to handle peak load but can support the average load.

High peak-to-average loads arise both directly (e.g. CEB, drill press) and indirectly (e.g. hydraulically-driven electrical generator powering an arc welder).

In a small-scale installation, the hydraulic system is often completely idle. When the system is in "standby" (nobody is using hydraulic power at the moment), the lines remain pressurized. If there is no major leakage, the main pump can be turned off and the accumulator will maintain pressure. When a tool is connected and fluid begins to flow, the pump will turn on. A small-storage accumulator can seamlessly provide hydraulic power while the pump starts up. The pump turn-on can be triggered by a pressure drop or by an accumulator-capacity sensor.

For these applications gas-bladder accumulators are at least as suitable as raised weights. The compressed-air/hydraulic [http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.158.30 "open accumulator"] achieves much higher energy density than a gas bladder with a tradeoff in increased complexity.

=== Pulse absorption ===

Hydraulic shock and surge loads arise from valves that open or close quickly or actual mechanical shocks that are part of the tool operation. It is helpful to isolate the main distribution system from these shocks, which can cause momentary peaks or dips in pressure to other tools, higher frictional flow losses, and extra stress on the distribution piping. Small gas-bladder accumulators located close to the tool (either incorporated at the tool itself, or at the quick-connect outlet it is fed from) serve this need.

== Constant-Pressure Tools ==
For use on a constant-pressure shop supply, a tool's flow path should be ''blocked'' (no flow) when it is not in use. In contrast, on a constant-flow mobile system, a subsystem's flow path is ''open'', through the "power beyond" valve gallery to tank return, when it is not in use. This is a concern for tools which incorporate their own valving; for example, it may be necessary to make a porting change in order to connect a [[CEB Press]] to the constant-pressure shop supply line. On the other hand, a simple actuator which connects to the LifeTrac hydraulic takeoff (and expects to be controlled by the LifeTrac HTO control valve) will operate equally well from an appropriate "shop" control valve connected for constant-pressure supply.

== Hydraulic pressure transformation ==

In most multi-circuit hydraulic applications, efficiency is poor because the operational cycle requires the load pressure and load flow to vary widely, but the prime mover/pump can only be optimized for a single pressure/flow operating point. Efficiency is improved with load-adaptive pumps (variable displacement, load sensing circuits). However this technique optimizes dynamically to a single circuit's load and does not scale to many circuits driven by a single pump -- the situation in a constant-pressure stationary hydraulic power distribution system.

[[File:PWM_flowcontrol.png|thumb|240px|PWM transformer to drive constant-flow load from constant-pressure system]][[File:LinyiGuTransformer.png|thumb|240px|Using two valves, this design dynamically transforms to either higher-pressure/lower-flow ''or'' lower-pressure/higher-flow]]
[[File:IHTfloatingCup.png|thumb|240px|Hydraulic transformer "floating cup" design from Innas BV]]
Efficiency and other benefits accrue with the availability of "hydraulic transformers" which convert input hydraulic power at one pressure/flow level to hydraulic output power at a different pressure/flow level; this is most useful when the transformation ratio is dynamically adjustable. Four approaches are:
* piston intensifier (fixed transformation ratio): pressure applied to a large-area piston pumps fluid from a small-area piston, typically using a "stepped" piston with two different diameters.
* pump intensifier (fixed transformation ratio): a fixed-displacement hydraulic motor drives a fixed displacement hydraulic pump where there is either a different displacement per revolution or a mechanical gear ratio between the motor and pump
* "reverse hydrostatic drive": a hydraulic motor drives a variable-displacement hydraulic pump.
* [http://www.innas.com/IHT.html this] proprietary hydraulic transformer made by Innas
* [http://www.me.umn.edu/~pli/papers/RannowIMECE2006.pdf switch-mode] hydraulic transformer like this from Cao et al [http://dx.doi.org/10.1115/IMECE2006-13453 ], [http://sklofp.zju.edu.cn/lygu/SMHPS.ppt] in China
Note that the last two approaches are relatively new (less than a decade old).

A switch-mode hydraulic transformer may be an effective way to operate constant-flow ("open-center"-design) tools from a constant-pressure stationary hydraulic power system.
[[Category:Hydraulics]]

PSoC Torch Height Sensing

2014-09-21T22:52:21Z

ChuckH: /* Cypress PSoC4 Pioneer Board for Capacitive Torch Height Sensing */

= Cypress PSoC4 Pioneer Board for Capacitive Torch Height Sensing =

We are evaluating whether this board can provide operating height sensing for an oxyfuel torch and initial height sensing for a plasma torch. This is an [[Sensing_Distance_from_Work_Piece|important funtion]] required in the [[CNC Torch Table]].

The PSoc4 ("Programmable System on a Chip") is a small ARM microcontroller with flexible peripherals. One of the peripheral functions is Cypress' "CapSense" capacitive touch sensing. A relevant demo project, using the Arduino-form-factor "Pioneer" board is [http://www.element14.com/community/message/76985 here].

Update: there is a smaller Cypress dev board now for only $ 4

[[Image:ProximityDetection.jpg]]

== ChuckH testing ==
=== 10 Jan 2014 ===
Important note on PSoC4 capacitance sensing: must use PRS clock mode to avoid nonlinear "dead spots" in sigma-delta A to D conversion.
===12 August 2013===
Make 4-sector ring for testing.

[[Image:QuadRing.jpg|300px]]
===29 July 2013===
Current thoughts:
# Coil spring support (see 24-July pics) is nifty for tolerating side impacts, but it swivels too freely about its vertical axis. Maybe it's just too cute and we should use a solid piece of conduit instead.
# I am skeptical about the performance of the ring sensor over edges, holes, and anything else that is not a simple uniform plate of metal.
## Simple minded control would cause torch to dive down when approaching an edge or passing a cutout
## Logic could tell z-axis to "hold position" (i.e. stop tracking) if we know that an edge or gap is coming up, but this would require much more sophisticated and brittle CAM programming
## My preferred solution would be a 4-sector ring, and assuming that at least one sector will be over solid metal. There may still be corner cases missed by a "track Z by the closest sector reading" policy but not many.
## Most commercial cap-sense ICs are set up to handle lots of inputs (i.e. keypads) so this is only a ring-fabrication and wiring issue. Making the ring out of PC-board material sounds good.

===27 July 2013===
[[Image:Flatring500_150.png|thumb|0.05-in steps .50-.15-.50 in]]
Results from new flat aluminum sensing ring
# Signal is large, had to adjust PSoC A to D parameters to avoid overload
# Easily discriminates .050 inch steps, verified up to 0.5 inch standoff
# Loss of signal strength at edge of plate: 0.25 inch standoff over solid plate measures the same as 0.10 inch standoff centered over plate edge.

===24 July 2013===

Working on a new sensing ring featuring
# Made from sheet metal, the larger electrode area should provide more signal
# Coil spring mount
## Protects against accidental damage because it bends when hit but springs back to original position
## Coax signal line runs through hollow center of coil spring, providing a grounded secondary shield
## Wood split clamp provides electrical insulation for ring

[[Image:RingOnSpring.JPG|160px]] [[Image:ring_on_spring_test.jpg|480px]]

===21 July 2013===

We would like to place the circuit board in a shielded enclosure a foot or so from the torch itself, especially in the case of plasma torch application. Therefore I tried connecting the sensing electrode through about 2ft of coaxial cable. I used RG6/U type "CATV" coax (used with cable TV and antennas) because it is a foam core, low-capacitance cable, nominally ~16pf/ft. The PSoC chip supports "driven shield" so I used it. There are two subtypes of driven shield, "precharge by Vref buffer" and "precharge by IO buffer", it is not yet clear which is most appropriate.

To help protect the CapSense input pin from noise spikes (specifically a concern about plasma torch RF noise damaging the chip) I placed a 12pf capacitor in series with the sensing electrode. I made a ring shape out of insulated 14AWG solid house wiring:

[[Image:RingElectrode1.jpg|640px]]

[[Image:RingElectrode2.jpg|320px]]

Initial tests show plenty of signal close to the plate (the steps in this staircase are 0.050 inch movements), but sensitivity dropping off by 1/4" or so:

[[Image:full050steps.png]]

However the following technical issues need to be explored:
# Is the sensor adequately protected against plasma noise damage?
# How should the system reject long-term (time, temperature, etc.) drift?
# Will there be enough signal for oxyfuel cutting height tracking?
# Despite using shielded (coax), there is still some sensitivity to objects near the cable and circuit board.
# How will the system respond to sensing near the edge of a workpiece (where only half of the ring is over the work)? An informal check showed significant signal loss.

In addition we have to develop code which uses the distance sensing information to control a z-axis motor. This could run on the RAMPS Arduino, or it would be possible to execute this code on the PSoC4 Pioneer board; it has a pretty capable microprocessor. For that matter, the PSoC could also handle arc voltage sensing for a plasma torch.

CNC Torch Table 2/Control Overview

2014-09-21T20:52:40Z

ChuckH: /* Oxyfuel (oxyacetylene, oxypropane, etc) cutting torch */

{{Template:Category=Torch Table}}

=Overview=
<html><img src="https://docs.google.com/drawings/pub?id=1SKGaBa6N21DPzXm9ILuqwPubc6nnRSBAARbkKaEU9hw&w=480&h=360"></html>

=Motor controller and drivers=

==RAMPS==
Dan's using [[RAMPS]] in Oct 2013 to get the table up and running ASAP. The plan is then to replace it with something beefier so we can go faster.

==Alternatives==
See [[Stepper Motor Controller]] and [[Stepper Motor Driver]].

=Software=

==G-code Prep==
[[File:Toolchain.svg|thumb|toolchain pathways]]
[[ImplicitCAD]] (see also [[Parametric_Design_Pilot_Project]])

[[Gcodetools]]

[[DXF_to_G-code_Conversion_Tutorial]]

[[Computer_to_Microcontroller]]

Nesting software would be useful. Example commercial product [http://www.mynesting.com/ here]. Anything open source?

[[DXF_to_G-code_Conversion_Tutorial#Piercing|Gcode preheat]]

Correction for torch cut kerf width ("cutter compensation" in CNC lingo) needed. G40/G41 but grbl does not interpret these.

==G Code Runner==
aka firmware aka motor controller (distinct from motor driver)

This is the firmware running on Arduino which converts a series of G-code commands to step/direction pulses for the drivers.

===Marlin===
When Dan Benamy was getting things going again in Oct 2013, he was using Marlin because grbl doesn't work with RAMPS out of the box. Marlin also has pretty much out of the box support for 2 drivers feeding 2 motors on Y which we use for out long axis because it has 2 motors.

* I cloned marlin from github and checked out the Marlin_v1 tag.
* Edited Configuration.h
** #define MOTHERBOARD 35
** #define DISABLE_E true // For all extruders
** #define TEMP_SENSOR_0 0 // Since we don't have temp sensors
** #define TEMP_SENSOR_1 0 // Since we don't have temp sensors
** #define DEFAULT_AXIS_STEPS_PER_UNIT {128.9304,142.5,200.0*8/3,760*1.1} // nov 1 2013- x and y are the right ballpark for the ose torch table at fef, see https://github.com/OSE/CNC-Torch-Table-OSE/issues/4#issuecomment-27460371 for where these numbers came from
** I set the "*ENDSTOP_INVERTING" consts as appropriate for our endstops by running gcode M119, seeing if an endstop was triggered, pushing the button, and running M119 again. If the logic was backwards, I flipped the appropriate boolean.
** I set the travel limits. There are 6 starting with "X_MAX_POS". I set the mins to 0. I set x and y max to 300 and z max to 150 for testing. Once we're calibrated and the table is fixed, we'll make these much bigger.
* I made home = 0,0,0 = the corner of the torch table near the ping pong table with the tool head fully down. Then I can stand at one end of the table and look down at it and it the standard x is right, y is up orientation. And when looking at it from the side, positive z is up.
* Edited Configuration_adv.h
** Uncommented "#define Y_DUAL_STEPPER_DRIVERS". I used Y because Marlin doesn't support dual drivers on X. We'll use Y as the long axis, X as the short axis, and Z as height. The 2nd Y will be output on the 2nd extruder port (E1, http://reprap.org/wiki/RAMPS_1.4#Wiring)
* Edited pins.h
** In the section for motherboards 33, 34 35, added "#define Y2_STEP_PIN 36", "#define Y2_DIR_PIN 34", and "#define Y2_ENABLE_PIN 30". This is a Marlin bug and I've submitted a fix upstream- https://github.com/ErikZalm/Marlin/pull/635
* Opened Marlin/Marlin/Marlin.pde in the arduino ide and clicked to compile and load it to the arduino.

=== grbl ===
When someone (Chuck?) was working on using the steppernug, they were running a modified grbl fork https://github.com/chuck-h/grbl/tree/edge. Changes from standard grbl [https://github.com/grbl/grbl]:
* Hardware I/O reassignment for steppernug interface
** different pin assignments on Arduino
** I2C extender
* substantially revised [[CNC_Torch_Table_Control_Overview#Limits_and_Homing|homing code]]
** dual X axis
** deep changes to stepper drive algorithm (implementing independent-axis trapezoidal move control during homing, as opposed to standard coordinated-axis move control for cutting) which should improve performance on long, limited-aceleration axes like torch table X and Y.

==Sending G Code to Firmware==

In Oct 2013, Dan can't find host software (gcode sending) that works with marlin. He tried about 8 different programs. For now the process is to use Printrun/Pronterface and copy/paste 3 or so gcodes at a time into there, wait for them to execute, and run the next batch. Pasting them all at once fails (machine does the wrong thing) probably because the instruction buffer in marlin isn't big enough.

See [[GcodeCommunications]] for a list of programs to send the g-code file from a host computer to a controller.

===Hardware===
Talk to Arduino with USB, or for longer distance RS422 e.g. [http://www.mouser.com/ProductDetail/Maxim-Integrated-Products/MAX3488ECSA+/?qs=sGAEpiMZZMvbyeSUH4qH%2fEqdkzg%252bEBoj MAX3488E]

== Testing ==
[[Stepper_Testing|Testing]]

Here's a test gcode file which Dan Benamy hand wrote. It works on marlin and draws a 2 hole by 1 hole plate- https://github.com/OSE/CNC-Torch-Table-OSE/issues/20

=Limits and Homing=

This whole section hasn't been updated for the Oct 2013 work using RAMPS. See https://github.com/OSE/CNC-Torch-Table-OSE/issues/11 for some of this with RAMPS setup.

Also note that docs from before Oct 2013 refer to the long axis as X but with RAMPS and marlin we had to make the long axis Y.

==Dual-motor homing==
The x axis (long axis) has 2 stepper motors. In the steppernug system, these have separate driver modules which receive identical step, direction, and enable signals.

For zeroing, the x axis needs to decouple - so if we get the x axis out of parallel, we can jog the x axes back into parallel by hitting their home switches independently. Steppernug supports this by allowing the Arduino to control a gate which blocks step pulses to the second driver module; in this condition the second motor will freeze and only the first motor will move. There is no provision for moving the second motor without moving the first, but that function is not required for the homing algorithm.

==Axis sequence==
# We will home the Z axis to its upper position first, just in case there are obstructions to clear during the X and Y axis homing.
# X and Y axes will do their initial fast moves to find home simultaneously (overlapped homing) to save time.
# The Y precision home movement will be performed.
# The dual-X-axis precision home maneuver will be performed.

==Limit and home switch configuration==

[[File:HomeLimit.PNG]]

''(TODO: add illustration showing distance coded reference mark options)''

''(Unconfirmed proposal at this time)'' [[User:ChuckH|ChuckH]] 23:42, 20 October 2012 (CEST)

Each axis has two switches: a '''limit switch''' and a '''home switch'''.
* The '''limit switch''' is activated at *either* end of travel. Its function is to protect against machine damage.
** Attempting to move further into the limit when the limit switch is active will cause all axis movement to stop, the torch to be shut off, and any other "safe shutdown" operation to be performed.
** The limit switch could be hit if the program erroneously commands the tool to move beyond the edge of the table
** The limit switch could also be hit if the torch table loses step (e.g. by hitting an obstruction) and subsequently performs a movement which takes it to the edge of the table
** The limit switch ''may'' be implemented as two physical switches wired in parallel, or the machine construction may permit a single switch to be used.
** Repeatable precision of actuation point is not very critical.
** This function is especially important if the table is expected to do automated cutting without constant human supervision.
* The '''home switch''' transitions between inactive and active at a point partway through the legal travel of the machine.
** For example, it might be active at the negative end of travel, and go inactive after 6 inches of movement.
** The home switch is used only for locating a repeatable zero position when the machine is powered on (or when recovering from lost steps)
*** Note that the logical "machine zero" coordinate may be placed at any programmed position relative to the physical home switch.
** Repeatable precision may be important
*** For the dual-motor axis, to establish accurate squareness
*** For all axes, to pick up in the middle of an interrupted job
*** If fixturing is used for repeat "production style" operations
** (''update, 14-July-2103:'') Instead of responding to a single flag location, the home switch could be actuated many times by multiple flags along the travel, with carefully designed nonuniform spacing between flags
*** This implements "distance coded reference marks" (DCRM), e.g. [[http://www.rls.si/en/dcrm-distance-coded-reference-mark-system--15934]], [[http://www.heidenhain.de/presentation/posa/en/index/N10584/N108A7/N10926.html]], [[http://www.newall.com/upload/content/file/SHG-TC%20-%20Distance-Coded%20Protocol%20-%20USA%20Ver%2004-07-05.pdf]]
*** DCRM is often applied to incremental linear encoder systems; the same principle is effective here using motor step count as the "incremental scale".
*** Using DCRM, the axis only needs to traverse two flag transitions after startup in order to unambiguously determine absolute position.
** By construction, the home switch is active at one end of travel and inactive at the other
*** This allows the machine to know which end of travel it is at in the event the limit switch is activated
*** This, in turn, allows the machine to permit recovery movement from the limit condition back into legal travel, while ignoring a command to go further into the limit zone.

There is an alternative switch configuration which places individual limit switches at the positive and negative limits of legal travel. However the configuration above is preferred because it supports faster homing and simpler control logic. Specifically:
# The substantial distance between the end of travel and the home switch location gives the machine overtravel room to do a controlled stop from high speed: maximum slewing speed can be used during initial homing without risk of slamming into the physical end-of-travel.
# Home switch placement can minimize the typical startup time.
#* If an axis is usually parked near one end of travel, the home switch can be placed there
#* If the axis position on startup is random, placing the home switch in the center of travel will minimize the average seek time.
#* DCRM can be implemented to obtain short startup/home times no matter what the starting position.
# The "safety shutdown" limit-switch function can be always active, and is independent of homing
#* The alternative approach requires logically repurposing a limit switch as home switch during home operations

==Switch Types==

The steppernug interface provides 5V power to sensor switches so either electronic or mechanical switches are easily accommodated.
* Mechanical microswitches are simple and effective.
* A Hall switch (e.g. [[Hall_Effect_Sensor_Module|this]]) is rugged but its position precision is probably only suitable for limits, not home switches.
* An optical interrupter (e.g. [http://www.mouser.com/ProductDetail/Sharp-Microelectronics/GP1A75EJ000F/?qs=%2fha2pyFaduhmXejJv184BikaBEqZykWweNnmsglkeuWVbMieAKIiNg%3d%3d Sharp GP1A75EJ000F]) can give precisely repeatable homing.

== Switch response time ==

The home switch should respond within one motor step time at the "creep speed" used for final approach. This speed might be ~100 steps/sec which gives us ~10ms.

The limit switch should respond quickly enough so that an emergency stop initiated by the switch will stop the machine motion before it hits a mechanical stop. This time is dependent on a lot of different design parameters, but is probably at least 10ms.

The limited response speed required allows us some latitude for noise suppression.

Since all switch signals pass through the I2C expander for I/O, there is about 150 usec (0.15ms) added, see [[Stepper_Testing#timing|here]].

=Torch control=

Software can use an M code to start the cut (e.g. open cutting-oxygen valve, strike plasma arc).

A second M code could shut down the entire torch (e.g. at the end of an unsupervised cutting session).

See also [[CNC_Torch_Table/Research_Development#Cutting_Torch]]

==Plasma Torch==

[[Plasma_Cutter_Design#Plasma_Cutter_PC_Interface]]

[http://www.metalwebnews.com/howto/plasma/presentation.pdf This presentation] on plasma-cutting accurate holes also suggests that ramping down plasma current while torch is still moving is good practice. (It makes the electrodes last longer.)

[[Sensing_Distance_from_Work_Piece|Z-axis arc voltage height control]]. Needs design work.

[[Plasma_Cutter_Cut_Speed_as_a_Function_of_Metal_Thickness|Cutting speed]]

Hypertherm:

[[File:PlasmaSpeed.jpg|400px]]

==Oxyfuel (oxyacetylene, oxypropane, etc) cutting torch==

During cutting, an oxyfuel cutting torch is literally burning the steel with a blast of oxygen; most of the heat comes from oxidizing the iron. However to start a new cut ("piercing") you must preheat the steel, relying on the acetylene or LPG for heat. After the steel is red hot you boost the oxygen flow and make the cut. We will want an oxygen-rated valve controlled by the microprocessor. "Oxygen-rated" mostly means the valve is thoroughly cleaned of all oil or flammable solvents that tend to explode on contact with pure oxygen; good practical reference [http://www.gmcscuba.com/pdf/CONVERTING%20DIVE%20TANKS%20FOR%20OXYGEN%20SERVICE.pdf here]. A solenoid valve like [http://www.lesman.com/acatalog/ASCO_8210_Oxygen-Service_Valves.html this] in combination with an ordinary regulator would give basic on/off control, but see better suggestions below.

Fairly technical application note about how to do good oxyfuel machine cutting from ESAB: [http://www.esabna.com/literature/Gas%20Apparatus/Miscellaneous/Oxy-Fuel_Cutting_Quality_0558006464.pdf]

[http://www.cnczone.com/forums/cnc_plasma_waterjet_machines/98346-cnc_oxy_fuel_discussion-25.html#post778595 This] ''long'' forum thread contains a lot of information about implementing small-shop CNC oxyfuel with programmed preheat, pierce, and cutting gas controls, auto ignition, etc. Based partly on this information, here are some control design suggestions for an Arduino-based CNC like [[CoolRAMPS]] or [[CNC_Torch_Table_Control_Overview#Steppernug_Driver_and_Interface_.28alternative_to_CoolRamps.29|Steppernug/grbl]]:
* use dome loaded regulators (e.g. Victor DL700 [http://www.amazon.com/Victor-0780-1188-DL700-500-Dome-Regulator/dp/B0047684PG] [http://victortechnologies.com/IM_Uploads/doclib_8016_DocLib_2331_56-0679%20%20DL%20700%20External%20Dome-Loaded%20Regulator%20Part%20Bulletin.pdf]) driven by regulated shop air [[File:DL700.png|thumb]] [[File:VTS250.png|thumb]]
** general description of spring- and dome-loaded regulators [http://www.documentation.emersonprocess.com/groups/public/documents/bulletins/debul2008x012.pdf here]
** It appears that almost any standard screw-handle regulator can be converted to "dome loaded" by sealing up the housing cap and replacing the screw/spring with an air pressure fitting. See video below. A classic dual-stage like the [http://victortechnologies.com/IM_Uploads/doclib_8039_DocLib_2310_56-0623%20VTS%20250%20Series%20Regulators.pdf VTS250] should work very nicely for conversion
** As with manual regulators, if oxy- or fuel-tank pressure exceeds inlet rating of dome-loaded regulator, a first-stage tank regulator will be required.
** With the dome-loaded regulators, gas on/off as well as pressure setting can be obtained with low-cost shop air components and small valves (e.g [http://www.ebay.com/itm/4V130C-06-DC24V-Solenoid-Air-Valve-5-port-3-position-/290652595990 4V130C],[http://www.automationdirect.com/adc/Shopping/Catalog/Pneumatic_Components/Pneumatic_Valves_-a-_Accessories/Solenoid_Air_Valves_-a-_Accessories/5-port_(4-way),_3-pos.,_Body_Ported_-z-_Manifold_(AVS-5,AM_Series)/AVS-523C1-24D AVS-523C1])
** Using a [http://www.digikey.com/product-detail/en/MPXHZ6400AC6T1/MPXHZ6400AC6T1CT-ND/2057456 solid-state pressure sensor] for feedback, the Arduino can set the regulated pressures to programmed levels by actuating the pneumatic valves (increase/decrease loading pressure until feedback is correct). See video below and code on [http://github.com/chuck-h/ose-gaspressurecontrol github].
* use an electric igniter ([http://www.americanrvcompany.com/Dometic-2931132019-Reignitor-Refrigerator-Part-Camper-Trailer-RV RV fridge igniter], [http://www.amazon.com/GrillPro-20620-Electric-Button-Igniter/dp/B000FJVKNM BBQ igniter], [https://www.sparkfun.com/products/11218 spark coil]).
* follow the sequencing of x,y,z motions, pressure changes, on/off, and ignition described by the folks on the forum thread above.
** Develop a library of pressure/time/positioning parameters for different material thicknesses and tip sizes that can be applied automatically by the G-code programming; this should minimize setup time and tweaking.

<html>
<script type="text/javascript" src="http://s3.www.universalsubtitles.org/embed.js">
(
{"video_url": "http://www.youtube.com/watch/?v=H3Z3EHqTn44"}
)
</script>
</html>
<html>
<script type="text/javascript" src="http://s3.www.universalsubtitles.org/embed.js">
(
{"video_url": "http://www.youtube.com/watch/?v=WcUnHnZJ8xU"}
)
</script>
</html>
<html>
<script type="text/javascript" src="http://s3.www.universalsubtitles.org/embed.js">
(
{"video_url": "http://www.youtube.com/watch/?v=uwCbohxajOY"}
)
</script>
</html>

Installing a [http://www.clippard.com/part/MNV-1K needle valve] at the solenoid air valve improved control smoothness a bit compared to video above.

[[Image:ClippardNeedle.jpg|300px]]

=== oxygen ===

The cutting oxygen for the torch must be high purity (according to the ESAB note above less than 95% purity simply will not cut steel, and >99.5% is required for best quality). Until recently, this meant cryogenically separated oxygen, depending on a large capital plant, and thus the user must rely on commercially provided tank oxygen. For some 30 years, [http://en.wikipedia.org/wiki/Pressure_swing_adsorption pressure-swing-adsorption (PSA) separators] have been available, but standard designs do not remove argon and therefore result in about 95%-oxygen, 5%-argon output gas. PSA construction is low-tech and works very nicely at small scale, e.g. portable breathing-oxygen units, and would be quite suitable for OSE. 95% purity is probably adequate for the preheat flame (ChuckH conjecture). For higher-purity cutting oxygen, PSA can be extended with additional zeolite materials [http://www.ou.edu/class/che-design/a-design/projects-2007/Oxygen%20Generator-Presentation.pdf] or activated carbon [http://www.airsepcpd.com/airsepcpd/pdfs/12779.pdf]; despite [http://cr4.globalspec.com/blogentry/20384/To-Build-an-Oxygen-Concentrator-or-Not this discussion] there is no clear record of small-scale DIY implementation of 99% oxygen PSA.

=== oxyacetylene ===

Recommendations from Victor:

[[File:Victor_Oxy_Acetylene.jpg]]

Commercial oxy-fuel machine cutting heads
* [http://www.pierce.cz/production/components-for-building-and-retrofiting-cutting-machines/autogenni-motorizovana-rezaci-hlava.htm?lang=en Czech] one with capacitive height sensor feature

Components offered by JB: [[CNC_Torch_Table_Log#Oct._21.2C_2012]]

== Oxy-propane, -natural gas, etc ==
[http://www.cousesteel.com/AndysPlace/PropaneAcetylene.html Propane] instead of acetylene. Note the large preheat oxygen flow (not in a consistent stoichiometric ratio to fuel) in this chart. Odd.

[[File:VictorLPGcutting.png]]

Would [[Gasifier|gasifier-gas]] or [[biogas]] & oxygen work? Probably, as natural gas is primarily methane and is a commercially successful cutting-torch fuel.

=See Also=
[[Distributed_CNC_Motion_Control]]

[[Category:CNC Torch Table Prototype II]]
[[Category:Vann]]

Anthony douglas log

2014-09-21T19:51:41Z

ChuckH:

=June 18=

Wow, did I not do any logging sing june 3? Hm. I have been using dropbox instead for my documentation. Honestly, the wiki is just too kludgy, slow, has too many limitations, and requires an internet connection, which we often don't have for one reason or another.

Dropbox also sucks, though, I have noticed it fails to sync, and this has been a real barrier in a number of cases.

I am there fore trying to switch to google drive.

The publicly accessible link to the google drive folder is here:
https://drive.google.com/folderview?id=0B12wZ5LxhSYndWNpaVViMU5tNkU&usp=sharing

Google drive Sync sounds a lot like dropbox. We will see.

The torch table is now moving in a way that is quite accurate, less than 0.18% linear repeatable error, which can be reduced further by changing a file. Basically it will be more accurate than our best measuring instrument, the calipers.

It is highly repeatable, not missing steps or slipping. After 5 times around the table it was within 0.2 mm.

I got the z axis under control of the arduino yesterday, so it can be controlled on a relative position basis in gcode. It also has a manual control. The z axis is important even in this open loop fashion to aid in piercing, and to ensure the tip does not snag on slag piles.

I think it will be relatively easy for someone who knows C to implement the feedback loop for the arc voltage and z height from this point. I am learning C now but hope to be gone real soon, so it won't be me.

The toolchain for the files is working except for circular holes, which should be a minor problem, to the degree it might take about 3 person hours to process the Liberator's .dxf files fully, to account for kerf, lead in and lead out, and the pathing order is also ok. I have tested it on ld-3, one of the brick press parts, and may do more later today.

Processing for piercing is working, we can get reliable piercing. It requires that you open the gcode and modify it manually, but the process is reliable and really quite fast, it only takes a couple minutes of person time. Gabriel has modified the lasaurapp to insert the pierce gcode in the right places, but the gcode is hard codded in, so if we need to change the timings that is a bit of a problem, although we can ssh into the beagleboneblack and change the source.

Cut quality is still poor with oxy. Ultimately oxy is a poor technology for the application, it has a wide kerf, is messy and more hazardous, has very poor accuracy due in large part to variable kerf, and produces vast amounts of heat compared with plasma. These latter 2 in particular are real deal breakers re a serious fabrication machine. The former is nearly self explanatory, although you can make some things with poor accuracy, it is one of the fundamental enabling characteristics of manufacturing methods, and we really do need more than the 3 mm over 25 cm oxy is expected to get. The latter means that accuracy is even more poor for holes, because the heat causes excessive melting.

We should not waste any more time on oxy. We have to stop this feature creep stuff and actually decide what we want, then go do it.

Although the reader may hope to be able to get it working better by getting the parameters worked out, the fundamental limits I describe are widely accepted in the industry and will not be overcome. I am doubtful that it might be useful to someone somewhere because it supposedly has a lower operating cost, because those operating cost figures assume cheaper gasses than such people will probably have, and they are perfectly capable of doing this figuring out themselves. Even if we get oxy working as well as it can with our poor quality equipment, they be almost back at square one as they will have different equipment anyway, and we cannot describe many of the settings quantitatively, which means they will not be able to use it anyway practically. We will not be adding to the knowledge base by further work on oxy. And in any case, we should be spending our time on the *most* important things, not just random things that are kind of maybe useful.

The only reason to continue with oxy is to use it ourselves, and it makes a poor tool anyway, as mentioned.

The shielding is the main thing that needs to be done to use plasma. It is no minor task, but manageable. I would have been working on it, but I can't even turn on the plasma cutter without an air dryer, and Marcin is not willing to get anything other than a very particular $400 refrigeration based unit which is mail-order only from harbor freight.

So progress has essentially come to a halt.

Gabriel and Aidan and to some degree maybe Stephen and whoever they bring on board will take this from here.

My task is mainly to document and backup things before I go, make sure they are accessible. Fortunately almost 80% of the stuff I have done here is also useable for plasma.

As a final note, I need to talk to Marcin on what the reason for insisting on Oxy was, as it has been a serious mistake that has prevented progress, but is compounded by the failure to move on getting the plasma ready in time to keep up with development.

A machine that cuts metal parts to good tolerance, with a good cost to performance ratio, that is open source and passably well designed and built. That is what we need, and nothing else will do.

=June 3=
Here is the link to the dropbox folder: https://www.dropbox.com/l/UqQL7SkTXMTFwY38YEfrdo? . You should be able to download anything in the dropbox from that page, or all from a .zip file. This approach of a dropbox, plus a publicly accessible link, allows us to practically upload and sync files from our computers, and to a lesser degree phones, which is good for videos and pictures, while also ensuring anyone in the world has ready access to them for a relatively long way in to the future. Hopefully a couple years, I have no idea what dropbox's policy is. Within a year the info will be mostly obsolete, though, as the next version of the table should have been implemented, and the results published.

Ultimately it should all be on the wiki, for the longer term (OSE implements periodic wiki backups), but the wiki has a 50 meg file limit, is slow as molasses, limitations on file types, needs things need to be manually updated, and is otherwise impractical, in the end, to use.

=June 1=
I uploaded the backup of the dropbox folder today, to the wiki, for the torch table. The next step is to import things into the dev board. I haven't been doing that as I have been the only one working on it. The file should be named Dropbox_folder_for_torch_table_and_router_v2_may24_onwards.7z on the wiki when the upload completes.

Today I was looking into doing a repeatability test with the table, to see if we can detect any/when the steppers skip, basically, and what they skew of the table is. The thing is that it looks like it will be a lot easier to do with a working z axis. And that shouldn't take too long to get working. The main problem is that I don't know much C. So I spent about 5 hours today learning some more, and then I will need to learn about the arduino environment specifically, then it's a very minor matter to get the arduino to accept input from a switch and output to the drivers.
=May 29=
I have made some more progress on the torch table. The main thing right now is piercing. The oxy torch needs to stop briefly before it proceeds with each cut line, to allow time for the operator+torch to turn on the o2 lance and proceed with cutting. I was experimenting with the torch, and I think it may not be able to pierce while the o2 lance is on, but further experimenting with the gas flow rates is called for.

I have tried several approaches to get the thing to pierce:
-Use a line segment of different color at the beginning of each cut, and tell it to cut very slowly there. Doesn't seem promising as the system cuts all non-black lines first, instead of going in the order in which they appear on the cut diagram. I also had to figure out where the lasersaur starts the cut lines in order to decide where to put the red lines, and need to add this discovered logic to the documentation (it's in my notebook presently).
-Use the manual pause button in the lasaurapp interface. Impractical because lasersaur takes a few seconds to actually pause after you tell it too. Oi.
-export the processed .svg as g-code, then modify the g-code and feed it back to the driveboard. A promising approach, except after modifying the g-code, which took a good part of my day, I discovered there is no way of actually getting the driveboard to simply read a g-code file. The g-code is part of the internal processing; the svg is converted to a g-code file, then the g-code is fed to the atmega from the bbb, which interprets it as it is streamed in. K. But there are no provisions for circumventing the svg-processing part and using g-code directly. This is a fundamental omission, I think, as during testing and hacking, you always want to be able to test a system piecewise, and the flexibility loss you suffer by omitting piecewise use of the machine is a real problem. As seen here; we want to do something ever so slightly different than the designers had in mind, and the system is relatively hard to shimmy into this role.

An important lesson to remember when designing future systems. Although if I knew more Python and linux it would still be manageable, modifying the source code is still a level of bother that is a lot greater than just having provisions to import and execute a g-code file, which the system almost inherently has. I may pull something off in this vein yet.

Remaining to be investigated are:
-Get the system to read a g-code file that I put on the bbb via ssh.
-use the stop mode to pause/resume the cut manually. Again, timing is a problem.

In other news, I repaired the interned connection in the shop by running a cable down there, after being stymied by not having the passwords for the router and isp, and therefore not being able to do it using a wireless connection.

I did not order the pcb or parts for the capacitance sensor for the torch table yet, because I found the arduino is capable of implementing basic capacitance sense capability with almost no additional hardware, and frankly I was going to but got dragged away to work on the microhouse, and manage personal stuff which takes a lot longer than it ought to under these conditions. However the range and signal to noise ratio might not be as good as the separate sensor. So we might have a problem there, or we might have a particularly elegant solution in the end. It's a small gamble.

A lot of my time has been consumed with helping with the microhouse, which is not so micro any more, having it's size tripled, plus a big deck added. We spent all weekend on it, and some time on Monday and yesterday.

I also really need to put a lot of this down to figure out my travel itinerary, and get tickets etc. Getting out of here is a real problem, as getting a ride out to a normal city is difficult.

I still don't know when I will leave, it depends on when can get a ride, and what my investigation of low cost travel options reveals. There are also still a few parcels that have things I need to take with me which are taking forever to get here. My time here has been epic and life-changing, as I expected, but I frankly started wanting to leave some time ago. 2.5 months is more than enough time here.

So ultimately the priorities right now are the torch table and the documentation thereof, and getting out of here.

=May 24=
Some more progress on the torch table has been made, but I have been able to spend quite little time on it, overall. Yesterday I had to go in to town, help plant the garden, etc. and today we are building the microhouse porch.

Bittorrent sync has problems regarding edit conflicts - it sometimes wipes out recent changes made to a file, so we are switching back to dropbox. To see the files in the dropbox, this link should work for anyone who wants to see:
https://www.dropbox.com/sh/i28hx6enwcl9u8b/AAC7BtGtDiiY-BALI6rrYp-6a

There is nothing there at present. I need to copy the stuff from the bittorrent sync folder, but currently the computer that has the stuff on it is somewhere else, apparently not connected to the internet, because it is not syncing with me. I thought Kyle also had a copy of the folder, and this other computer did. Apparently not. So now I am stuck without the files I had been working from.

=May 21=
I have made some progress on the torch table; it now operates over the whole table. I spent quite a bit of time on attaching the limit switches. Got some progress on piercing logic. Was not able to find any metric bolts or allan keys in the hardware store, so we still cannot attach the z axis unit.

The plan for the z axis is to order the pcb and parts for the sensor, assemble it with one of the arduinos here, and one of the stepper drivers (we have a spare), and hopefully Skylar can program the arduino, otherwise I can hobble to do so.

The gases will be constantly on, for now. To terminate a cut you just move the torch head extra fast, which the controller will do automatically for us anyway, since it is just transiting from the end of one cut to the beginning of another. This might end up leaving a slight tail or notch in the piece, though. A way to control the O2 valve would solve this, but I don't know if the operator could control it, as you'd have to time things just right, such that you turn it off just as it finishes the cut, which I don't think you'd be able to do very well anyway.

For now, this will be a pretty crude cutting system, but it will make a solid platform for use as a plasma torch table later.

I have made much less progress on this than I could have, though, because I am constantly pulled away by a million other things here. Not distractions, just things like helping to take a fence down, trying to find a way to get into the city to do essential personal things, get some new shoes, stay clean and fed, stay in shape, find a place to work without constant disruption. All minor things here are much more time consuming, and this decimates the time I have to spend on the actual reason for being here rather than somewhere else.

I think this is a problem that can totally be solved relatively easily, but it requires changes in the culture and infrastructure, something too long-term for me to practically work on, given I am leaving soon.

=May 16=
Got the torch table x and y finally mostly working today!

Next, I need to change the working area of the system, attach the limit switches a bit better, speed up the steppers. try an dvg file down the tool chain, probably affix and hang the cables a bit better, then we need the z axis controller. Then some sort of logic for piercing looks like the next hardest issue.

It occurs to me that almost all the time spent thus far was on saving money, and not very much, either. Also, that much of that time, in turn, was spent overcoming limitations like a lack of electrical tape, etc. which are very inexpensive things. Clearly there is much room for increasing the rate of development work here. We could have been where we are now two weeks ago.

A video of the table moving can be found in the torch table stuff folder. It is currently stuck in a corner of the table, because I have the stepper motors turned down to 1/16 steps per pulse, and because the driveboard etc. software constrains the working area to what it things is the size of the lasersaur bed.

I have added some info to the documentation files in the torch table folder, as well. I think the approach of using more general pupose tools is turning out to be much better and more powerful already. Just basic things like inserting a table, making sure you don't loose your work, etc. is easy, by applying tools better suited for the task. If it takes 4 times as long to do things with a given tool set, then you will only get 1/4x as much done in any finite time.

=May 15=

I have been making some progress on the cnc torch and router table. Here is some documentation on wiring and parts I took an hour to make today, for anyone doing something with it in the future.

There is a copy of everything in the following bittorrent sync folder, too, view only key:BXKD32CVOIQBVYLHYXNPCJLAKPQWWBMYU.

It takes forever to upload anything, it should be named Torch_table_stuff_summer_2014.zip so you should be able to find it that way. I may or may not have the chance/remember to put the file url here later.

One thing that looks like it might hold us up is the z controller, I haven't heard anything from skylar about it at all.

=May 13=
Things have been going well on the torch table. I have been seriously under the weather, but hopefully will be doing better soon. These are hard conditions to operate under, even after I have had time to set up some.

Tyler has got the mechanical drawing of the existing table done. We have made a lot of progress in picking apart and understanding the driveboard from the lasersaur, and in overcoming the usual huge number of minor barriers, and I made a wiring diagram for us to follow:https://docs.google.com/drawings/d/1tT_dwtOEHOU2znsg3k915PcJW_YMGrmoXdlzTLb3FdY/edit . We have an ongoing problem with the conflict between the advantages of google docs for sharing vs. the severe performance limitations it has. I think a good approach is to use google drive, or better yet, bittorrent sync (although version control and edit conflicts are a problem for that). Then we can use practical, general purpose tools, but still share the files. Granted you can't edit them in real time like this, but for a lot of stuff you don't have more than one person editing it anyway at one time. However the documents can still be readily shared, including withe world.

Google docs is good for performance requirement documents, etc. but it is too slow and limited for a lot of stuff.

There have been a lot of false starts, unfortunately, but basically we are focussing on getting the xy robot working from .svg files, and then tacking on a separate z axis controller and a bunch of manual intervention to cut to a useable oxy-fuel torch table of sorts. You will have to stand there and supervise it, ignite it etc. though. There are no gas control valves, ignition, pierce detection or flame-out detection, etc.

This is largely because plasma is a more accurate technology anyway, so what we really want is plasma. And integrating the z axis with the driveboard controller is also an important thing to do, so it can be used for milling, to reduce manual intervention, etc.

=May 5=
Ok, so we made some progress on the torch table today. Tyler is drawing the existing table in Solidworks, Devin is up to some stuff, and I was assembling a list of parts, and things we need to do, with a focus on the things that we are most sure will need to be done sooner or later. Doing these things first helps to ensure that the time spent is not going to be thrown down the drain later; it provides a sort of known-good way of getting at least a bit of traction at the beginning of the project, which will be built upon.

Now I need to sort of save my work by doing something someone else can build upon, if I were to disappear tomorrow, for example, and also to communicate with the rest of the team what I have learned and whatever news I have.

Things to do: There is a document on the kitchen table we are using to add todo things and things to acquire as we think of them. It would be nice if we could have both a high level of accessibility of the kitchen table document, while also the benefits of a google doc, but ultimately if we have to pick one it seems like the paper is still the better choice. Google docs just are too slow and take too long to access. I noticed that they are usually forgotten and remain unused, with the result that we fail to keep track of things or use documentation altogether. Having a shopping list on paper that we actually use rather than one on google docs that is not accessible, forgotten about, or for whatever reason not actually used, is not as good, ultimately.

Ok, so after having a look at the lasersaur manual,

Very basic system diagram thus far, it is far from detiailed or complete. I don't know yet if we need a 24 v psu.. The stepper motors are actually 4.5 volts, 2.5 amps. It depends if anything on the driveboard or the motor controllers actually needs 24 v, or if it is only used for other things, i.e. switched by but not used by the drive board.

The current set resistors should be about 26.1 kohm, or something close to that, according to the equation in the lasersaur manual.

We may be able to use the same driver to drive both x axis motors. otherwise, it looks like just parallelizing 2 drivers should be fine.

I looked up the motors, and they are probably compatible with the lasersaur software. The steps per mm of travel will need to be adjusted, hopefully that won't be too hard.

a toolchain example is .svg file (vector graphic from e.g. inkscape) -> bbb, then streamed to the atmega on the driveboard, which does the gcode interpreting, and handling the state of the robot.

Looks like we can defeat all interlocks and the door switches easily enough. The main safety interlock can double as a master power switch, apparently.

There is a spare stepper motor in this box of electronics, here. We can probably use it fine, although it occurs to me generally that we have a problem at OSE with a poor stock of standard useful things, which really slows things down and holds things up, sometimes. The just in time thing doesn't work well here. It's another story, but it would probably not be a bad idea to have a couple extra arduino, stepper, screwdriver bits, 5/8 inch bolts etc. just handy as a matter of course.

For z height control ultrasonic looks promising still, but making our own ultrasonic sensor is a small project of it's own. An arduino avr or pic, stepper controller, we can use the power supply from the lasersaur (5v) and the same stepper and gecko drive looks like the most promising approach. We could use a different, smaller and cheaper stepper driver, but we have a spare or even two of the geckos, so I don't think it makes sense for now to try to use a different driver. My main standing concern is the beam path of the ultrasonic sensor, and the supposed 1mm resolution of the sensor. The positional envelope we want to stay in is +/-1/16', only 1.5 mm, so you want higher resolution than that, really. The commercial ultrasonic based controllers don't do anything about the beam, I noticed. They just measure slightly to the side of the torch head.

link to edit and view the document:t
<html><iframe width=100% height='900' frameborder='0' src='https://docs.google.com/drawings/d/1lnLfF9f3C9OKZBMUT5onRaV4g4zPDihh_IF-hMiryLo/edit'></iframe></html>

Standing questions, which I hope to improve on, tomorrow, include:
-brushes for the flats to keep out debris? This could end up being important to avoid jams, although easy to improvise it may need to be done wone way or another.
-power supply situation?
-how easy is it to set the steps per inch
-use a compensation table with the lasaurapp?
-we need to get on with ordering the stuff like limit switches etc. Assemble part numbers, consult the others and combine their lists, do some shopping and email MArcin a list of stuff, distinguish between what will be needed sooner or later for progress, and what is nice but optional, or based on the current proposed way forwards.
-acceleration and deceleration rate of the steppers needs to be addressed to avoid missed steps
-general mechanical fit of the system needs to be investigated, and what needs doing identified

I read a bit on existing models and projects, and found the Torchmate growth series table, which is a commercial version that is a lot like what we are trying to do here, apparently. It is a table with replaceable toolheads that can do milling and routing, too. Not accurate milling the way a bridgeport, for instance, can, but it could do the rough machining and bulk removal which would really help a ton.

= April 30 =
The CEB press was completed in the nick of time, and Scott, the buyer, will test it further before leaving for far off places with it. Retail price is $9k, plus you need a power cube to run it, 2 for 12 bpm. The accuracy of the blocks coming from the machine is excellent, we got it to within 1/16 on all dimensions for a couple of test bricks.

Interestingly, the accuracy on the width-wise dimensions, which stems from the width of a plasma cut plate of steel, is within 1/64th, which comes from the accuracy that the plasma cutter has. So basically the accuracy of the cutter was successfully leveraged there. It seems clear to me that it can be elsewhere, too, and that this will cut the labor requirements of manufacture a great deal.

The Microhouse structure and roof is also done, with only some more interior stuff like putting the the very last of the laminate flooring, ladder for the loft etc. in left. Now the main focus is the torch table.

I haven't actually bought a ticket yet to anywhere, for better or for worse. The thing is that it changes so much here depending on who else is present, what the current focus is etc. that I might as well almost be in a different place. I had thought that I had really had my fill and it was time to go soon. But I want to see how things go in the next week, as I am tempted to stay further, maybe another month even, if I find I am contributing a good amount and also learning a lot.

But today I really, really need to get in to Cameron to do some personal things. One of the major problems I have had here is the accumulation of personal things that I cannot get done because of the lack of access to the things present in a city, and secondly because of the increased time it takes to do normal routine things like cooking and cleaning that inhabiting in a group environment of this nature (which is not like some other group environments) entails.

I hope to get together with the guys and get some performance based design criteria down for the torch table, and place some orders for parts we know we will need, etc. We also need to ask Marcin about the history of the table etc.
=April 23=
Today was the last day of the Microhouse (structure) build. Tyler, Kyle, Devin and myself went down to the workshop to have a look and start the torch table development. We started a folder system using bittorrent sync to share files, hoping it will be more reliable than dropbox. We are going about making the design requirements, but still need to bring Marcin on board so things are congruent with the larger scale plans. From the look of things like now from what we know of the large scale movement of the enterprise, it doesn't look like it makes any sense to use the oxy acetylene torch. Instead, we should skip straight to working on the plasma torch head approach. Also, it may make a lot more sense to get this existing table working first, before we try to reach out to the advantages that gridbeam might bring. More of a bird in the hand worth two in the bush sort of thing. Aligning this table looks a lot easier than building a new one.

=April 20=
We had a great day yesterday; the ceb press was breaking down in a variety of interesting ways, difficult enough to figure out to be interesting and educational, but not enough to stop us. We have 5 different types of easily spotted jams, plus some software bugs which are harder to see happening unless you already know the software. Also it is not clear what the origin of some of the jams is; it may be that they start as software bugs but then become something else, which we would see as mechanical clogging, for instance. They can all be smoothed out relatively easily when we build the next press, I think. We stayed up late, I stayed till about 10 pm, pressing bricks. We figure we need about 3000 to 4000 bricks in total.

The drawer cloggage, bridging, bashing and jamming against the drawer roller,

Other bugs we spotted include the misalignment of the rear piston and the whole structure back there, the design of the top of the hopper area, etc.

The importance of an actual pulverizer became clear; a substantial fraction of the soil dumped on the grate would normally not go through, and we would brush it off or manually pulverize it, joking about how you might someday build a machine to do this (and some people of course chiming in with the old "zat would never work!" refrain while unable or unwilling to say even vaguely why they thought as much. It's particularly funny when people say that about something that you already are confident works pretty well and is widely used).

=April 18=
Hm, I've been pretty bad about filling in my log recently. Largely because there wasn't much to tell. We've been getting the place, mostly the hab lab, ready for the influx of 24 people for the microhouse workshop that starts on Friday. Tonight will be the inaugural dinner.

We planned for and bought food, did some more trim and painting, assembled bunk beds and moved things around.

After the microhouse workshop there is another one, and then we are going to be advancing the torch table project until mid May.

=April 15=
We assembled bunk beds, put in carpet, moved things around, etc. Kyle and Chris have arrived, so with James Slate it is more exciting here. We still have to do something about the food for 20 people, and dinner for 22.
=April 14=
Pretty good day today. We got what we expected to get done re preparing the infrastructure for the upcoming workshop. I volunteered to use the paint sprayer, a dirty task, but I was happy to do it as I am a fan of the use of labor multiplying machines like this. I discovered the spray nozzle was very poor, though. It, I gather, is supposed to put paint in a line. But it applies a great excess to the end of the line. The spray nozzle thing is fixed and non-adjustable. I don't know how they managed to do things this way, as it leaves a line on the wall of extra paint. I tried to compensate by moving the nozzle around some extra.

I also ran in to the problem of the paint being too translucent to cover the wall beneath sufficiently in one coat. The main limiting factor in how much you can put on in one coat is the formation of drips of paint. Particularly a problem for a ceiling, of course, especially one with areas that encourage flow to a point, as this one does. I was conservative for room 1, but on the next room I did I, in trying to find the optimum, put too much on, and got dripping. Nasty state of affairs. I reduced thickness for the next room, but not quite enough, still it wasn't nearly as bad. But I knew a second coat was almost out of the question, certainly with the sprayer, as the stuff needs to be put back in the room. We could cover things with plastic, though. Multiple coats of paint has always struck me as an absolutely abominable divider of labor power, though. I mean it nearly doubles the amount of work to two coats, and sometimes 3 is needed. Can we seriously not just invent a paint that has a better opacity to viscosity to drying rate performance, here? What if we add a thixotropic agent to the paint - thixotropic substances are liquid when they are under relatively high shear forces, but become solids when they are left mostly alone. So the paint goes on as a liquid, but it becomes a weak solid - sort of a gel - after application. That would certainly allow an increase in layer thickness. Or we could load more pigment particulates per liter of paint to increase opacity. It needs to be nearly double, though. What if we use flakes instead of spherical particles? If they aligned in the right way maybe that would improve the pigment per unit volume to opacity ratio. Especially if we could get them to align after application to the surface somehow. Make them electrets, or embed magnetic particles within them in the right orientation... or there may be some approach using surface physics or something. A paint that saved you from needing a second coat would sell like hotcakes to painters the world over.

=April 13=
Hey, where did my entries until april 12 go?? Well I ain't re-writing them now. Basically what has happened since the ninth is that we poured the foundation for the microhouse, planned what we need to do to be ready for the April 18 workshop, and got on with some of the ordering, and shopping. Dorkmo arrived yesterday, so that is great to have another person here helping. James slade is supposed to come down some time soon, too. There is a lot of painting, cleaning, fixing up etc. to do to ensure we are ready to house and feed 20 workshop participants for 5 days, then about as many for 3 days more after, for the CEB workshop.

We encountered an interesting situation in which we designed a bunk bed to build, needing 4 in the near term and 6 for the longer term, but found that the BOM would cost $125 at Menards, and a bunk bed on amazon.com would be $150 after shipping. It uses a metal frame, instead of wood. I think we may have been able to slash the price of ours by using less wood, or maybe we would find that metal pipes ended up cheaper. I think it is an important case study that should not be forgotten. We had a similar situation with the paint sprayer. We should be able to make stuff like this by now. When we look at the things we want made, we are not able to make them. Also, the things we want done, our equipment cannot do. Why? And why should we focus on ourselves, though? Well, if we look at the example of FOSS, I have read that the main reason it came into existence and was built to it's current point is that software engineers like it better, it making their jobs and lives a lot better and easier. The benefits that accrue to non-software engineers are mainly a form of collateral benefit. But we should expect such benefit.

=April 9=
Hopefully today we will finish up and power up the mixer. I have collected a lot of notes that need to be input and acted on, for the documentation of the next version of the source of the mixer. Then we need to do some stuff on the CEB press.

If I could only say one more thing here, it would be that I think it is also very important that OSE specify a set of standard fabrication tools, input materials such as stock, welding wire, etc. and training states for the people in it. By tools I include the building, safety garmets, drill bits, everything. The tools can be used for the training, I am currently quite persuaded that as long as safety is paramount you can learn over time how to do things effectively, with access to the internet and, ideally, a teacher here and there.

Things are really picking up, the weather is more hospitable, I think the next month and a bit are going to be very, very interesting and productive :).

I have been trying for a long time to learn both python and Inventor, and keep wishing I had learned it already. It's the nature of capital, of course, much like how many people who rent homes take a very long time to make a down payment on a house; accumulating capital is often pushed out because of the everyday press of other things, preventing long term progress.

=april 8=
We are very much expecting to finish the pulverizer build tomorrow. There is some trouble with the shaft, and the tooth bars just need to be bolted on, and that's it. The bucket also serves as a front end loader. Then we need to integrate the output of the build process into the product development, as enabling others to efficiently produce another unit is central to the enterprise. We have the time lapse as a record of the process, and also the time logs we have been keeping. I really wish, and I said this at the beginning, that we had a camera or several, documenting the whole process. The camera misses a lot. Even just now, I went in and asked if there were any shots of the shaft, so I could look at it instead of taking it all off to look at it. No. The shaft has been kicking around for many days of build time, and there is still no clear picture of it anywhere?

The real test, IMO, will come some time after the build process, to see how well we integrate the experience from the completely untested alpha into the tested once then overhauled beta version of the source code for the mixer, as well, of course how well the mixer works, and compares with units you can obtain in other ways.

=april 7=
Pretty good build day. I replaced the propane tank regulator this day, I think. I have been forgetting about my log to some degree, and will try to fill it in at the end of each day. When we are not actually at our computers the value of filling it in during the day is really too low.
=April 6=
Hoping to do just a little more today on the build, but I have a backlog of domestic work too, cooking, laundry, all that sort of thing that really adds up.

BTW for anyone who is not already aware, my plan is to stay till mid may, from the beginning of May the plan is to work on the torch table. But the soil mixer must be done for the upcoming workshops. I still need to install ubuntu on this computer, too, and there are some other things.

The hose for the hot water heater leaks propane, so that is a problem that we need to try to fix real soon, as it must be 2 or more pounds a day lost. We can turn it off except for showers, that will slash it severely. The welder was taking up a lot of time by malfuctioning, a problem that seems almost trivial to design around. The wire feed was incapable of overcoming the resistance to the motion through the liner and tip, is all. The liner is a ferromagnetic steel, so it collects filings etc. I think this was an important factor, as I disassembled and checked the resistance to motion on a range of counts, and it was only the liner that was unusually high, although still not that bad, it is kind of hard to push a wire. Sheer variety of things that can go wrong yet could be easily designed away seems to highlight to me how the tools around us are designed with criteria very different than what the user's desires are, which the users often blame on incompetence of the manufacturers, or just assume that it's harder than it is to design things to meet our needs better, even in the more obvious ways. I think the truth is that this sort of thing is mainly caused by the design criteria being so different than what the role and manner in which we want to use the tool.

In a way this is really important, because although the equipment designed at FeF may not seem super sophisticated, merely the congruence of what we are designing for and what the tool will be used for can get us enormous gains in the cost to performance ratio of the tool. The question is often asked of open source projects: how do you possibly expect to improve on the cost to performance ratio of the stuff from closed source, conventional manufacturers, when they have so much capital and experience at their disposal? I think this aformentioned reality is part of the answer. Ultimately the best argument is the success of prior open source projects, though, at doing so.

update: Good day indeed, today. The freedom of working on the weekend was actually very helpful, just being more free to use my time as I found suitable. Although I started later and stopped for an hour or two there, I got about as much and maybe more done, I think, and also got some domestic stuff done, too. I put the holes in the tine modules, then marshalled the nuts and bolts and got some kinks worked out there, got the welder #4 mostly working again by replacing the torch liner, finished welding the tooth bars, ground them, ground the angle plate in the bucket, tacked it in place, got the bearings fitting on the shaft and in place ok, got some progress on the motor mount, fixed a missing hole problem, and investigated some potential build and development process improvements.

=April 5=
It's the weekend! Yay! I want to go back to the workshop and do some more stuff. We try to take the weekend off, which I think is a very good idea, and enlightened. Enthusiasm and the energy that a project team has is not in opposition to making good decisions regarding a division of one's time.

The thing is that this is the sort of thing that I would love to be able to do on the weekend at home.

=April 4=
The wiki just destroyed all my edits, and my retrospective edits for the past 2 days, which included the build process. The edit window indicated "view source", and had the entries in the window, indicating they were part of the source of the page. Still, I highlighted the area and pressed control+c for basic disaster mitigation, so I would have a copy on the clipboard in case. Then I pressed f5 to reload the page to get an actual edit window, and while it was loading, right clicked, to be extra sure it copied it by clicking on the right click context menu. The copy etc. options were greyed out. The page reloaded and everything is gone, including in the history. I don't have time to add it back now, as it is 10:30 and we need to proceed with the build process.

I input my time sheet and updated my log for the last 1.5 hours. Time to go!
[[File:TIMESHEET_INPUT.ods]]
=march 31=
We have finished the dozuki guide today, I just went over it to check for bugs etc. now.

In the afternoon I finished limewashing 2 more hotel rooms, we will see tomorrow if they need another coat.

= march 28 =
We worked on the fabrication instructions today. There was some backtracking due to some co-ordination issues. The illustrations for the dozuki are also being made. My completed fab instructions need to be integrated with an older, incomplete version for which we have some illustrations, otherwise the illustrations would need to be re-done.

I did some limewashing got about half a room done, much faster than usual. The trick I developed was to splash limewash on, then spread it into an even layer with the paintbrush, because otherwise the rate of material transfer from bucket to wall is a major bottleneck. Not much limewash comes with the bucket. A super soaker type squirt gun would work very well here, greatly increasing the rate of limewashing, with the current mix. I doubt it would clog, and if it did you could unclog it periodically and still end up with a large improvement factor. Ultimately this shows the importance of actually going ahead and trying things out on the ground. There is a lot of gold to be found in both armchair thinking and research and discussion, but I think that what is often left off the table is the sort of exploration that just gave me a 3x speed improvement; it includes a certain skepticism regarding the essentiality of sticking with the usual approaches. Our situation is never exactly the same as what others face, and that opens up room for doing things differently. A sprayer may seem attractive, for instance, but it wouldn't help much at the perimeter of the walls anyway, because it would get a lot on the roof. Secondly, we only have a 1.5 rooms left for now, so investing the time and effort in inventing a sprayer makes little sense.

source note: to reduce cracking, spraying the wall enough that it darkens, then allowing it to sit for about 5 minutes helps a bit, to reduce cracks by maybe 35%. It is important with this method to start at the top and work down, or you get splashes and drip marks. Set up the ladder, fill the bucket only a bit full so it is comfortable to hold, paint near the ceiling carefully. Then you can start splashing. Holding the rim of the bucket close to the wall, use the brush to sort of paddle out limewash, to get it on the wall. Proceed in a line, and stack the lines as far as you can reach. Get an idea of how much a splash covers after spreading after a few full repetitions of the splash and spread, and spread your splashes accordingly. Then spread with horizontal brush strokes, followed by long vertical stokes for the desired texture. Any drips or splash marks should be gone over with the brush within less than a minute or two, or they may partially dry and leave an undesireable mark, although going over repeatedly with the brush can help reduce these. The brush abrades the wall and gets mud in the limewash if you scrub hard, so try to press lightly. We want a layer as thick as we can get without dripping (which with this mix, 1:1:0.2 by volume of lime, water and salt, does not appear to increase cracking over a thin layer), and to reduce the mud contamination in hopes on not needing to do a second coat, which would greatly increase workload. If you do need a second coat, try to use uncontaminated limewash.
=March 27=
disassembled tine module, for production of a 3d exploded view of the tine module [[SoilPulverizertines_disassembled.skp]]

=March 26=
A load of gravel came first thing today, I took a humble video and put it on youtube. (currently sideways, I'm hoping youtube will have the capacity to rotate it after upload, http://youtu.be/0BfR3y66ATk) Order from Sweiger shop for the steel placed ( based on what the BOM, accessible through the dev board through dozuki, specifies, minus what we had in stock, plus some extra while an order is being placed) . Got the hydraulic diagram up, too [[Soil_Mixer_-_Overall_Machine_-_Hydraulic_Diagrams]]. The only thing there really is the cushion valves, and it would be nice to know more about what lies within the lifetrac cabin, but this sort of system diagram, which specifies inputs and outputs, without bothering with the actual details of what is in the box, has many advantages, too.

In the afternoon we spread some gravel, I finished the interior painting and put the carpet and beds back, and put some carpet from the silo to put in the hab lab while the original tiles are awaiting washing. Whoever's idea it was to use carpet tiles deserves a thank you, as they have proven more suited to the hab lab than normal carpet many times. Some weak adhesive on the back of them would be good, though, as they stick up sometimes and you can trip on them.

=March 25=
Starting today at 9. The main thing is the bom and then the order from swieger (Sweiger?) shop, then the hydraulics diagram with google Draw. Andrew is doing the fabrication procedure.

google docs has a bit of a problem: when I go to the workshop, I can't edit the spreadsheet anymore, because google docs can't handle not having an internet connection. I cut and pasted the BOM into Calc for now, then will paste it back into the bom.

got he hydraulics diagram done, will put them up tomorrow
=March 24=
I worked on the bill of materials, then went and searched the workshop to determine what we did and did not have in stock here, and so what we need to order. I'm getting a bit more familiar with the shop, but I still missed some stuff that we had in stock, thinking we did not.... anyway, it was good news in the end, we have all the hydraulic parts, and many of the others, too.

Then we did some painting in the rooms, including our bedrooms, so we slept outside them tonight, because of the fumes. There is still more painting tomorrow, so it will be the same tonight. In the evening Marcin stopped by, and we did some review of the bom and what we had in stock, and what parts/materials need to be ordered for the mixer build. I'll review the bom again, knowing where the stock is kept this time, produce a derivative file that is less verbose as a list of stuff to submit as an order from swieger shop, then email Marcin the list, make any changes needed, and fax it to swieger shop using the faxzero.com service (why swieger doesn't accept orders by email I don't know).
=March 21=
Friday, we spent today on the mixer changing the DXF files in an attempt to greatly reduce the amount we'd have to pay the fab shop to cut the steel for us. By keeping the big plates and many of the strip pieces aside to cut ourselves from plate with a torch by hand or stock strops with the ironworker, we slashed the bill from $2000 to $750 or so. I made some progress on installing Ubuntu, too, and installing, freecad, openscad and librecad, mainly a matter of overcoming error after error.

We spent the afternoon limewashing and preparing a room for limewashing, then we started a narrated historical tour of FeF, which I'm hoping we can do more of on Monday.

=March 20=
We spent this morning, mostly, fixing a couple holes and propagating the changes through the dependent files for the mixer. We got 1.5 rooms of limewashing done, in the afternoon. I got eh ubuntu live usb working, after finding the computers would not boot from a cd, and I made some progress installing it. I was reminded that Linux installation always seems to have a problem with partitions; the installer is incapable of resizing partitions, and gparted is fritzy, so I boot back into windows to free up space on a partition, then will reboot to ubuntu to try again. Minor progress on the bom and also the fab drawings.

=March 18=
Starting in the design stuff. First, the review of the 3d model, then we can export to dxf for and, check the scaling, combine the dxfs into a single file in librecad so they can be cut from a 4 by 8 sheet. Andrew is presently increasing the polygon count, too, so those circles and stuff are a little more circular, as I noticed some of the holes on the CEB press are clearly polygons after cutting, although I suppose this is small fries, it is something that it would be nice to address for the future, to improve the cost to performance ratio in some cases. Actual round holes are a useful thing.

Export from sketchup to to-scale DXF file is now complete!

[[File:Soil_mixer-pulverizer_march_18_sketchup_to_dxf_CAM_files.zip]]

The orthographic views of the weldments are exported too, the next thing for them is to dimension them. That shouldn't take too long in Inventor. LibreCAD doesn't snap to the lines in the drawing, so the dimensions come out with long strings after the decimal point based on how closely you could get your mouse cursor, and you can't edit the text after, it just becomes lines.

But now we move to infrastructure stuff, mainly whitewashing that hotel room.

=March 17=
Design stuff in the morning was mostly spent getting Inventor working, looking into importing Sketchup files, reading about Geometric dimensioning and tolerancing, and investigating libreCAD for use in dimensioning the outputs of the sketchup to DXF converter tool. The afternoon infrastructure stuff entailed removing the rest of the adhesive from the front windows, cleaning up around the microhouse, painting much of the interior of the MH, then we did some consultation with Marcin on the design, and turned to domestic labor, getting food, firewood, etc. Later in the evening Andrew and I had a closer look at the 3d sketchup model and found a number of errors that we were glad to catch at this stage, but it means we should go over the model to double check things. I suspected this would happen, but it's not really regression, just part of the development process, I think, here. Not like loosing a file or something. We should be checking each other's work anyway, and expecting errors, especially when trying to shimmy a program like sketchup into the role we want it to fill here, and with all of us relatively inexperienced users of the software. Certainly not in all cases, but I think much more so than is usually assumed, teamwork of this sort can overcome the need - and mean real need, of course they would be able to do things faster, but as long as we get there in a reasonable time frame - for more experienced people.

=march 16=
My log entries keep disappearing, for reasons that are unclear. Some kind of conflict with the multiple tabs open. Anyway, today we cleaned the hab lab and got personal stuff done. One issue that has come up is the presence of CCA wood in the wood fuel pile, and therefore probably arsenic in the ash of the furnace and campfire. According some research just now, http://www.noccawood.ca/docs/ccawood.pdf indicates that a 12 foot long 2 by six contains enough arsenic to kill 250 adults. So I had to think for a second when I saw Andrew vacuuming up ash around the fireplace, releasing a cloud of it into the hab lab. It has probably happened before, though.

Otherwise, I have gotten Inventor mostly working, about 6 days after I first started trying, we cleaned up the hab lab, set some mouse traps, collected non cca wood etc. I have been trying to encourage recovery from my cold as much as I can, too. The time consumed by the tiredness is infuriating, indeed. I have been reading on dimensioning and tolerancing, and hope to learn and do some of that for the soil pulverizer this evening.

=march 15=
Turns out I actually have a cold, I realized last night, probably accounting for the voice and unusual level of tiredness recently. Great timing. From prior reading on the subject, apparently one of the only known orally consumed things that helps is 500 to 1000 mg vitamin C, if taken within 3 days of the onset of the cold, which going by the onset of the voice symptoms, is already passed. Normally I take 500 mg per day of Vitamin C for that very reason; so that the times that I do get a cold, I have been taking it, before it is too late, not having known whatever was wrong with me was a cold. The other thing is zinc nasal spray, but it has the side effect of a relatively high risk of destroying your sense of smell, permanently. Echinacea, the other preparations in the pharmacy, don't actually help address the tiredness, actual viral infection etc. I went into the pharmacy once and looked up the ingredients on the labels of all the nostrums. I suppose a cough suppressant might reduce transmissibility. I am coughing very little anyway, though. They usually resolve in seven to ten days but some can last for up to three weeks.[12]
http://en.wikipedia.org/wiki/Common_cold#Management

Done the final review modifications to the sketchup file, and exporting all parts to .dxf files. They are uploading now, the file named "Pulverizer anthonyd mar15 8 40 pm 2013.zip "[[File:Pulverizer_anthonyd_mar15_8_40_pm_2013.zip]](the wiki can only upload a single file at once, apparently, and indeed give errors if you try more at a time by opening multiple upload windows) Next we need to dimension it. We take the weekend off, but I wanted to do this as an exercise, partly; the thing is this is the sort of thing I normally do on my weekend, learning things and trying to check things off my todo list. It only took about 40 minutes so not too bad; otherwise I focused on advancing things that I can't do during the weekday 9 to 6 hours. I went to the shop to see if I could repair one of the bicycles for quick trips into maysville, and found that there is a bike in nearly working condition, just the front tire needs to be pumped up. Couldn't find a bike pump, though. Will have another look tomorrow. I discovered exercise equipment in one of the side rooms of the hab lab, and moved some of the equipment from the grain silo in there, so we have a compete kit. It brings to mind something someone printed out and left on the table here, the integrated human page from the wiki, advocating for, among other things, a balanced life style. I have not been exercising explicitly since I got here, really. Our bodies are a reflection, in part, of the lives we live, our history, so this heralds regression in my fitness levels, unless I can get a good exercise routine worked into my days here. The weights will really help, certainly, but in practice there is nothing like an actual gym, I know from experience. The intensity of the exercise can't practically be matched, it is mainly a matter of the geometry involved with applying an optimal level of resistance to the various muscle fibers over their range of motion.

Inventor is downloading yet again. Error after error, data corruption, incompatibility, their silly download manager complicating things by breaking down, amazing. They should just use bittorrent.

=March 14=

Something has malfunctioned with this wiki page, as my definitely saved entries for today have gone missing. I will have a look at the history later to figure it out. Anyway, in summary, we spent till about 2 on domestic labor, including cleaning and buying food, and taking a break to say goodbye. The afternoon was spent on whitewashing, painting, removing tape adhesive and other infrastructure stuff. Then we did a final design review of the latest soil mixer/pulverizer prototype. The slated changes are still slated, but I have gone ahead and extracted dxf files from the sketchup file for the parts that will not change. I will then go and export the changed parts, it shouldn't take long to change things and export them. Then we proceed with the dimensioning, to produce a set of drawings for fabrication here on the farm. The drawings will not be super fly, as it is for use here in the prototyping process, mostly. For example, even the plate parts should have edge views, but that would take twice as long to export the files, and it took me about 2 hours just now, and there is very, very little use for drawings of the side of a part made from a plate of uniform thickness when you have the face drawing and thickness.

'''Announcement to all others at OSE:''' Just know that my voice seems to be giving out. I'm pretty sure it is from all the talking, and near shouting. I noticed we tend to have to speak loudly due to background noise. I have probably put out more sound energy in the last week than any week of my life, I think! I seem to remember that it is very important to rest your voice when this happens, or you risk permanent damage. So I absolutely must talk less. When I do speak I will have to speak more quietly, too. Also I will try to use signals and gestures instead. I noticed I make the gesture for "I can't hear" a lot, the hand by the ear...:)

=March 13=
Last day for most of us present here. Yesterday Andrew, Marcin, Catarina, Chris and I talked about continuing to volunteer here longer, because Andrew and I do not need to return to school as the others do. The plan is for the two of us to continue to accomplish things here on the same schedule, of CEB press in the morning, and infrastructure expansion in the afternoon, until the end of April, which is absolutely great. I was uncertain and didn't want to seem clingy, probably I went too far with that, but it is a fascinating, incredibly worthwhile and rich project here, and I was very much hoping I would find there were opportunities to continue helping to advance it, and all the learning by doing that goes along with that.

todo:
Finish the pulverizer/mixer fabrication instructions for the overall and rotor, this includes adding some pics and the note regarding the relative position on the tines on the tine modules and a few other things (if the tine modules are identical, then the tines will all line up, which is not really what we want.) Doing this gives me a head start on doing the other parts, so I have that on my personal todo list and hope I won't have to jettison it, due to things on the list that I have committed explicitly to doing. Also included herein, is to get the drawings done thus far up on Dozuki. Inventor is done downloading, so I may be able to do something useful with that, too.

The afternoon will probably be lime washing and painting, and progress on the microhouse.

links or list for documents I have added to thus far, to be linked to for easy locating later, for now these are place holdersj:
The dozuki fab instructions guides and the wiki pages that are linked to from the master development board/spreadsheets for the soil pulverizer/mixer tool.
http://opensourceecology.org/wiki/Soil_Mixer_Design_Rationale

I've got most of the parts exported to dxf, and will do the modified ones tomorrow. I am taking a moment to note here, though:
=March 12=
Got an error message when trying to install the 32 bit version of Inventor, which took since yesterday to download. The 32 bit version won't run on windows 8, so I need to download the 64 bit, back to square one. The importance of having your means of production with you or handy. Andrew had a similar problem, not having his SolidWorks with him. Probably because he never used his laptop to with it.

The morning was spent progressing on the fabrication plan for the soil mixer/pulverizer. This is particularly helpful as it helps iron out some off the design details, such as the manner in which the tine modules interface to the rotor shaft etc. They can be found linked to on the wiki through Dozuki under "build instructions" for the overall and also for the rotor module. I would greatly prefer to add some images, but the feature to add images to the wiki of the existing pulverizer to make things more clear to the reader, and also for Dozuki was not functional at the time, though it seems to be working now for the wiki, so I may revisit this later.

The afternoon was spent moving the swimming pool (parts), limewashing, cleaning at the microhouse, moving lumber and other small tasks that add up.

Very interesting discussion around the fire last night, as you might hope when people who are interested in a project like this come together.
=Tuesday, March 11=
Morning design. Eric and I measure the tines modules and the more critical rotor dimensions, so he can model it in scad. I document the process itself, in [[Process used march11 2013 to model an object for concept sketch in scad]] [http://opensourceecology.org/wiki/Process_used_march11_2013_to_model_an_object_for_concept_sketch_in_scad]. My abilities in Inventor are too limited for now to do this in a reasonable time frame, I think, but I will download a copy now so I can try to draw things tonight. I decided to focus on other things until now, since there are others in the group who can draw well, to be the most effective team player I can. I still need to get the pictures I have taken up non trovebox, I was hoping to do so this morning, but the internet connection was down.

This afternoon I spent mostly on preparing the exterior wall of the hab lab, then limewashing it, and painting the interior with the yellow.

=Monday, March 10=
We made good progress in the design of the pulverizer/mixer, essentially settling on the high level design and finishing the 3d sketchup model. Going out to see the stuff was a great aid, and seemed to inspire and catalyze thinking in the group. In the afternoon I and some others focused on finishing the microhouse interior walls, with the chicken wire and plaster/pearlite mix. I returned in the evening and did another batch, timing myself it took 28 minutes to mix and apply a batch of the plaster mixture, we will certainly be done the lower layer tomorrow, then there is a final finish layer. I am going to bed now immediately after this, entering the log entry and eating, I think, as I have been getting increasingly sleep deprived over the past week. Yesterday and today I tried to remove the ton of malware on this computer with avg free, malwarebytes and the online trendmicro software, which have helped, but there is still something interfering with the browser severely.

=Sun Mar 9, 2014=
*Pulverizer and mixer design session in the morning.
*Afternoon work included cutting plywood sheets w/ table saw with Coltan, painting the boards, then helped mud up the cracks in the micro house, moving some scrap metal and helping with the dishes. One interesting thing was the difficulty of stuffing the mud into cracks and against the wall due to it's failure to stick well, then the discovery later in the day that mud near the fire was far stickier and would have been a great labor saver. It shows the importance of a brief practical exploration period. Another thing that made a huge difference, which I expected probably existed, was the technique Marcin showed us to get the mud in the walls; take a trowel with mud piled on it and force it against the wall with another, with the first trowel held underneath.

TightWire Alignment

2014-08-11T05:52:42Z

ChuckH:

Tight wire alignment is a technique for measuring straightness of large equipment components. ([http://www.powerhousetool.com/align.htm example supplier]) It has a long history although it has been largely displaced by optical methods. It may be appropriate for creating straight movement axes in [http://flowxrg.com/2011/12/01/concrete-lathe-manual-v1-10/ lathes], [[CNC_Torch_Table | torch tables]], and other machine tools (especially appropriate for [[Shonda_Research |concrete-bed, grouted-ways designs]] in a start-from-scratch model).

== Principle ==

A wire stretched between two points establishes a nearly straight line. Gravity causes a sag which can be predicted accurately if the tension (e.g. from a hanging weight) and wire material are known. The distance from the wire to an object of interest (e.g. a guideway, bearing housing, travelling slide, etc) is usually measured manually with a micrometer device which "beeps" on electrical contact with the wire.

== Optical sensor ==

As an alternative to manual micrometers, a close-up camera may observe the wire position. Kevan Hashimi at [http://www.opensourceinstruments.com/WPS/ Open Source Instruments] describes such an instrument for scientific work. Here we describe a low-cost adaptation to the machine-alignment task. The procedure for aligning ways is
* If no carriage exists yet, fabricate a kinematic slider to ride on the ways
* Place brackets (if necessary) and string a tight wire parallel to the ways.
* One wire support is a pulley wheel; hang a dead-weight for tension.
* Mount the mirror assembly (described below) to the carriage or slider, centered on the tight wire.
* Attach a video camera to the carriage, looking into the mirrors. Close focus ("macro") is useful.
* Run the carriage up the ways, recording video
* run processing program on the video, which will report deviations along the travel (sensitivity better than 0.0005 inch should be achievable)
* adjust ways with shims, repeat tightwire measurement.
* apply grout and allow to harden, holding ways in permanent alignment.

This sensor relies on a single camera looking at images of the tight wire in two small mirrors. The assumption is that some kind of electronic camera (webcam, cell phone, etc) will be available on an ad hoc basis, but is not permanently dedicated to the instrument.

=== Proof of concept ===

''Note:'' This is just a proof on concept "mock up", I don't think this design is stable enough to be usable yet.

For testing I used an LG Optimus cell phone camera. This camera can capture stills and moving video.

==== Parts of the optical sensor: ====
[[image:TightwireParts.jpg|400px]]

I used nylon "invisible thread" 0.005-inch diameter. Steel would probably be better (more opaque, for starters).

==== Assembled ====
[[image:TightwireAssembled.jpg|400px]]

The mirrors are placed so that the images of the wire (when centered) are colinear with the reference marks. By doing the video measurements relative to the reference marks we make the exact location of the camera non-critical.

==== Set up for checking lathe way straightness ====

The company where I work has a lathe, so I set up this trial on it.

[[image:TightwireOnlathe.jpg|400px]]

Sample camera frame:

[[image:TightwireStill.jpg|400px]]

Clearly some repositioning of the mirrors would help. Ideally we could get a reflected image comparable to this (which was taken with the same cellphone camera, but with no mirrors and a more careful setup):

[[image:TightwireCloseup.jpg|400px]]

The necessary image processing program has not been written. It could possibly be written as a macro in [http://imagej.nih.gov/ij/ ImageJ], a great open-source image/vision program.

Features needed:
* Extract centerlines of wire images (one in each mirror)
* Extract centerlines of reference lines
* Establish displacement of wire image from reference line
* Establish scale factor from spacing between the two reference lines
* Adjust for angle between the two reflected sightlines (it won't be exactly 90 degrees)
* Adjust for wire sag (need to know tension weight and density of wire material)
* Report table of x- and y- deviations from centerline along travel distance.
* Report deviations from straightness (i.e. deviation from best-fit straight line)

Shonda Research

2014-08-10T19:26:33Z

ChuckH:

new data dump

=tool dependency =

[[File:Tool flow.JPG|tool flow for the multimachine project]]

*types of machine tools capable of being build by concrete and floating precision (spindle requirements and any other precision parts listed) (manhy of the tool description are taken from wikipedia)

*the three basic requirements for building precice machine tools is ways for linear movement, housings for bearings and spindles, and flat matting surfaces for alignment. unfortunately to get all three of these at the required level of presision takes machine tools ... and it becomes a recursive loop. However if a purpose build temporary setup is made using dial indicators and precision levels (cheap, by first world country standards, tools) then the process can be boot strapped and one machine can make parts for a second and then between the two most other machines can be made.

*so starting with a the production of a lathe, the only precise parts are the spindle (bearings will be purchased and spindle is just a pipe, housing will be boot strapped or outsourced) and the rails (which only have to be long enough for making spindles for other machines (~2 ft travel). Once a lathe is built that can produce spindles for a centerlss grinder hardened shaft can be ground to tolerances of within a thousandth. then with spindle and way production capability a surface grinder or mill with surface grinding capability can be made. those three machines will give the three required operations of linear movement, spindles, and mating faces.

*lathe: a machine tool which rotates the workpiece on its axis to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry about an axis of rotation.
**requires: a stiff spindle(roller bearings generally) with a chuck adapter on the end, 2 axis or movement, one long way and another about ¼ the length of the long axis, a tail stock with a morse taper, a quick change gear box for threading parts (only on manuals, hybride and cnc will use tachometer and servos to thread)
[[File:Centerless grinder.jpeg|thumb|overhead view of centerless grinder]]

*Versamil attacment for lathe: a milling head attachment for the lathe with 2 axis of movement, a vertical linear travel (Y axis) and a rotary axis around the Y axis (B axis) plus a spindle with a quick attach plate for various attacment (milling, grinding, Gear cutting, off center drilling). this allows us to (much slower), create parts of this caliber [[http://www.youtube.com/watch?v=139z62o6OhA&NR=1&feature=fvwp]]
**requierments: a vertical axis (4 thinner ground ways mounted between plates), a motor mount with pulleys ending in a spine coupler capable of running 4 000 RPM),
*Centerless grinder: Centerless grinding is a method of material removal through grinding [[http://en.wikipedia.org/wiki/Grinding_(abrasive_cutting)]], similar to centered grinding except for the absence of the spindle. It has high throughput, i.e. a large number of parts can be manufactured in a short time.
** requires: two accurate grinding spindles (4000 rpm and around 100rpm respectively), one of which should be able to rotate 10 degrees and travel to increase the diameter ground, and the ability to align both spindles and work blade along the same axis
*mill: A milling machine is a machine tool used to machine solid materials. Milling machines are often classed in two basic forms, horizontal and vertical, which refers to the orientation of the main spindle. Both types range in size from small, bench-mounted devices to room-sized machines. Unlike a drill press, which holds the workpiece stationary as the drill moves axially to penetrate the material, milling machines also move the workpiece radially against the rotating milling cutter, which cuts on its sides as well as its tip. Workpiece and cutter movement are precisely controlled to less than 0.001 in (0.025 mm), usually by means of precision ground slides and leadscrews or analogous technology. Milling machines may be manually operated, mechanically automated, or digitally automated via computer numerical control (CNC).
**requires: three axes of linear travel (2:1:1 lengths) and a spindle, aditional axis can be added for more utility and easier use.
*surface grinder: Surface grinding is used to produce a smooth finish on flat surfaces. It is a widely used abrasive machining process in which a spinning wheel covered in rough particles (grinding wheel) cuts chips of metallic or non metallic substance from a workpiece, making a face of it flat or smooth.
**some of the work that a surface grinder would do can be done with a Milling machine that can run 4000 rpm but at lower accuracy
**requires: three accurate axis, and a grinding spindle
*cylindrical grinder: The cylindrical grinder is a type of grinding machine used to shape the outside of an object. The cylindrical grinder can work on a variety of shapes, however the object must have a central axis of rotation. This includes but is not limited to such shapes as a cylinder, an ellipse, a cam, or a crankshaft
**requires: 2 axis of linear movement, one turn table, and two spindles (one lathe, one grinding)
*drillpress
**requires: quill (allows a spindle to move along its z axis while maintaining accuracy), and spindle. everything else is preference for moving tables and slides.
*bandsaw (vertical and horozontal): for cutting stock to size
**requires: heavy hindge(horizontal) or linear (vertical), and hydraulic clamps (possible autofeed of stock)
*arbor press (hand or hydraulic): for seting parts on an arbor or broaching holes, etc
**requires

=links for yahoo multimachine lathe=

*description of centerless grinder setup [[http://www.fivesgroup.com/fivescinetic/en/News/Articles/Documents/Centerless%20Grinding%20Article%2001_05_07_MMS.pdf]] [[http://www.buffaloabrasives.com/prod_details.php?cat=6]]
[[http://www.efunda.com/processes/machining/grind_centerless.cfm]]

*link dump for multimachine meta-project.

*taper dimension links [[http://www.victornet.com/reference/Morse_Jacobs.html]]

*pipe schedule chart [[http://www.crestwoodtubulars.com/pipe-schedule-chart.html]]

*bearing suppliers in st Joseph [[http://www.applied.com]][[http://www.ibtinc.com/]]

*VersaMil attachment for milling on a lathe [[http://concretelathe.wikispaces.com/file/view/versamil.pdf]][[http://www.amazon.com/Milling-Operations-Lathe-Workshop-Practice/dp/0852428405/ref=sr_11_1?ie=UTF8&qid=1213590781&sr=11-1]]

*Ohio source for hardened and ground shafting plain or predrilled (quote for 2X 8' long 3" O.D. 60RC rails $1500)[[http://www.nookindustries.com/linear/LinearShafting.cfm#PreDrilled]]

*spirit level accurate to 5 ten thousandths over 10" costing $61.25 [[http://www.grizzly.com/products/Master-Machinist-s-Level-8-x-0005-Per-10-/H2682]]

*original patent for concrete machine tools by Lucien yeoman (I think) [[http://flowxrgdotcom.files.wordpress.com/2011/07/4622194_process_for_forming_concrete_mac.pdf]]

*main site for the graphic designer for the yahoo lathe multimachine group, Tyler Disney [[http://flowxrg.com/]]

*yahoo groups for the multimachine [[http://groups.yahoo.com/group/multimachine/]][[http://finance.groups.yahoo.com/group/Multimachine-Concrete-Machine-Tools/]]

=Review=

==Chuck==
21-Sep-2011

Great work, Shonda! Adding some thoughts/reactions.
* Consider building centerless grinder first. Use this to produce rails for lathe.
* If necessary, follow up the centerless grind by lapping with a ring lap. It should be possible to obtain ways with diameter consistent to a few tenths.

=== Lathe ways ===
I like the idea of adjusting two ways straight and parallel then grouting in place. The classic vee-flat ways (or round-flat) are kinematically correct. Parallel round ways are overdetermined. Nonetheless, my suggestion is to use parallel round ways but design the carriage to accommodate slight variations in way spacing.

Adjusting ways to straightness is an interesting challenge. Even a 10-second precision machinists level may not be up to the task in the vertical, and doesn't readily handle horizontal straightness. My suggestion is to go optical.

The traditional technique is [http://services.eng.uts.edu.au/desmanf/AdvMan/MetroLabs_Autocollimator.pdf autocollimation]. However, I have cooked up some optical techniques based on using an ordinary consumer digital camera and software.
* as with traditional autocollimation, we need a kinematic sled that rides on the guideways (two vees on the main rail, a flat on the secondary rail), which is advanced along the rails in steps equal to the stride between the two vees.
* the sled carries a digital camera instead of a mirror.
* for one type of measurement, the camera axis is parallel to the ways and the camera is focussed on a distant fixed object (preferably through a window/door, several hundred feet away). Open-source software (e.g. [http://opencv.willowgarage.com openCV], [http://rsbweb.nih.gov/ij ImageJ]) can establish image shifts to sub-pixel accuracy. This technique can measure angular deviation to a few seconds of arc.
* for a second type of measurement, the camera overhangs the lathe bed and faces down towards the floor. At floor level there is a trough of water; the upper surface of the water reflects the image of the camera and sled. Once again, a very small tilt of the camera axis is detectable as a shift in the position of its reflected image. This measurement functions similarly to a precision level but may be more sensitive.
* in both types of measurement, an open-source computer script can handle the computations and identify the location, direction, and size of corrective movement needed to straighten the ways.

===Carriage===
The carriage must engage the ways with a large area of contact to ensure rigidity and good wear life. This requires an internal half-cylindrical surface accurately mated to the ways. My best idea so far is to drill a slightly undersize hole, split into halves, and finish lap to size.

Two such half-cylinders, well-spaced, could be grouted into the carriage to follow the main guideway. The second guideway would also have a half-cylinder shoe, but an intermediate flat-against-flat (or, alternatively, a "rocker") arrangement would accommodate slight variations in way spacing without disturbing main guideway tracking.

===Lathe bootstrapping===
It is possible to turn parts between dead centers before the headstock is built. This might be the way to turn bearing seats on the spindle.

===Linear encoders===
Linear encoders are expensive. Here is a possible alternative. The [http://www.southwesternindustries.com/documents/SWI/swi/Support/Documents/DRO/Technology.pdf Trav-a-dial] has been around for decades and really works. Put a [[Rotary_encoder| rotary encoder]] on it and you have a high resolution linear encoder system. A grit wheel concept (like the HP drafting plotters use) might also work.

[[Category:Personal Logs]]

Vegetable Oil Production

2014-04-05T23:54:20Z

ChuckH: /* Applications */

== Overview ==
OSE principles suggest minimal use of petroleum products, which often means the substitution of locally produced vegetable oils. Oil crops are also likely to be grown for edible cooking oils. In either case, appropriately-scaled oil processing technology is required.

== Applications ==

* Cooking oil
* [[Hydraulic_Fluid |Hydraulic fluid]]
* Motor fuel ([[Biodiesel]])
* Lubricating oil (e.g. [http://www.hort.purdue.edu/newcrop/proceedings1999/v4-247.html][http://www.hort.purdue.edu/newcrop/ncnu02/v5-029.html])
* Paints/coatings
* [[Induction_Furnace_Overview#Resonating_Capacitors |Electrical dielectric fluid]] [http://abiosus.org/docs/5_Biermann_ApplicationOfVegetableOil-basedFluidsAsTransformerOil.pdf],(IEEE [[media:F03-EsterFluids.pdf | tutorial]])

== Crops ==

* Canola (modified rapeseed)[[http://www.hort.purdue.edu/newcrop/nexus/Brassica_rapeseed_nex.html]]
* Soybean
* Sunflower[http://www.hort.purdue.edu/newcrop/nexus/Helianthus_annuus_nex.html]
* Flax (Linseed)

== Processes ==
[[File:oilseed_refining.png |thumb]] [[File:Hydraulic_cage_press.png |thumb|An open-frame hydraulic cage press which could be re-implemented with the CEB]]
[http://www.cyberlipid.org/oilseed2008.pdf Small scale processing paper] from ATTRA

Oilseed pressing [http://www.appropedia.org/Original:Small_Scale_Vegetable_Oil_Extraction on Appropedia]

[http://science-in-farming.library4farming.org/Crops-Grains-Protein/OILSEEDS-OILS-AND-FATS.html at Library4Farming]

[http://www.rivendellvillage.org/oil_extraction.pdf from Practical Action]

Description of conventional Refined/Bleached/Deodorized(RBD) process in [http://www.freepatentsonline.com/20110204302.pdf this patent application]

The cage press method of expressing oil involves loading seed into a squeezing compartment, applying at least 500psi (higher pressures, up to thousands of psi, improve extraction efficiency) to crush seed and express the liquid oil, then removing the remaining solid oilcake. It seems that with appropriate simple modifications (a perforated pusher block above the moving press foot) the [[CEB_Press |CEB Press]] could perform this function very effectively.

[http://www.aseanfood.info/Articles/11023786.pdf Separating Oil from Aqueous Extraction Fractions of Soybean] examines the use of aqueous (basic) sodium hydroxide solutions for extraction of oil from soybeans processed with different means. A sodium hydroxide mixture is found to be 80-90% efficient but processing to lyse cells is key to a high yield. Lipid droplets are also complexed with lipid binding proteins (oleosin) which can complicate downstream processing.

[[Category: Food_and_Agriculture]]

Induction Furnace Overview

2014-04-05T23:12:51Z

ChuckH: /* Crucible */

{{Template:Category=Induction furnace}}
==Overview==
{{Induction Furnace}}

==Introduction==

The Open Source Induction Furnace Project seems to be the most promising way to implement the [[foundry]].
This project involves the design of:
* a high-power induction furnace circuit (between 20 and 50 kW), and
* the melting chamber proper

==test==
Well, we could buy a turnkey system perhaps for $5k total used, and run it from the LifeTrac generator. The only disadvantage to this route is that if it breaks we’re dead-in-the-water – either with the impossibility of fixing closed-source technology, or a high repair bill. A single component which blows and is inaccessible for fixing could in principle turn a working power supply into worthless junk. Thus, it is worthwhile to tame this technology by open-sourcing the design.

===Goals===

To fulfill our [[foundry]] goals,
The furnace should have the following characteristics:

#Induction furnace or any other technology that can do this within a budget of 40 kW of electric input, with minimal pollution
#Suitable for melting all metals and alloying
#150 lb per hour steel melting furnace for casting
#240 v ac, 40 kW power source available

(This spec implies ~260watt-hr/lb, which may be optimistic -- see [[Induction_Furnace_Overview#Melt_Calculations |Melt calculations]])

==Conceptual Diagram==

This is a conceptual diagram of the entire Induction Furnace system from the [[Global Village Construction Set]]. The furnace is powered by 20 kW of 240VAC electricity from the [[LifeTrac]] generator. The entire system includes the power electronics, induction coil, and heating vessel - into which metal for melting is inserted. This diagram intends to document the relationship of functional components in the induction furnace system, as a basis for technical development of components and their integration.

The electronics part should be adaptable to different metals and different metal melting coil geometries. Melting coils should also be modular, such that the power electronics can feed different coils. Basic functions include selection of heating frequencies, which are required for melting different metals or metal geometries. There should be a feedback in the electronics, where the amount of power given to the coil should match the quantity/geometry of metal being melted.

[[Image:induction_concept.jpg]]

==Details==
The complete design should include all of the following:

===Induction Furnace Circuit===
# Scalable from 20 up to 50 kW (perhaps even more)in units of 1 or 5 kW
# Allows for power and frequency range selection for different materials and heating devices
## small crucibles ~50kW, ~1kHz
## heat treating small parts ~5kW, ~100kHz
# Incorporates self-tuning to track the coil resonance dynamically during operation
# Power source may be either 1 or 3 phase electrical power
See also [[Induction_Furnace_Overview#Power_Supply |Power Supply Notes]] below.

===Heat Dissipation System===
Specifications of a cooling or heat dissipation system.

===Coil===
# Modular, adaptable design specifications for primary coil windings
Water-cooled copper tubing coil. Compute skin depth at operating frequency in order to estimate useful thickness of copper section.

=== Yoke ===

In lower frequency furnaces, it seems a cylindrical iron or steel yoke surrounds the coil, forming part of the magnetic circuit, increasing coil power factor, and thus improving efficiency. This Turkish manufacturer [http://web.archive.org/web/20100205092811/http://www.demora.com.tr/index.php/meltshop/induction-furnace/magnetic-yoke.html] uses 0.3mm (0.012in) thick laminated transformer steel for the yoke. See also the useful description of the art in [http://www.google.com/patents/US5247539 US Pat. 5247539]

Steel laminations begin to have high losses at the 1kHz frequency level and soft magnetic composites (e.g. iron powder [http://www.hoganas.com/Segments/Somaloy-Technology/Home/ Somaloy]) might be considered. The biggest problem seems to be that the powder needs to be compressed at 20-50 tons/sq in in order to get good magnetic properties. A bit much for the CEB! Also poweder cost is unknown.

I also looked briefly at steel wire for the yoke but [http://www.pmt.usp.br/academic/landgraf/nossos%20artigos%20em%20pdf/03lan%20smm%20mag%20wire.pdf this paper] was not encouraging.

===Resonating Capacitors===
Modular capacitor bank to accommodate different coil inductances and operating frequencies in different applications.

Induction heating capacitors carry high currents and larger sizes are usually water-cooled to deal with their internal heating. Typically polypropylene is the primary dielectric (due to its low loss factor), combined with dielectric oil and sometimes an additional kraft paper layer. Commercial suppliers of capacitors: [[http://www.celem.com/ Celem]] [[http://www.geindustrial.com/publibrary/checkout/Material%20Safety%20Data%20Sheets%7CIHM_design_aid%7CPDF GE]]

If these high-power capacitors are to be made of local materials, the DIY Tesla coil community (e.g. [http://4hv.org/e107_plugins/forum/forum_viewtopic.php?60477], [http://wiki.4hv.org/index.php/Rolled_foil_capacitor_-_60_kV,_3.5_nF]) may have useful experience.
For oil-filled-paper designs, castor oil has a long history in HV pulse applications and canola[http://www.petroferm.com/datasheets/357_TDS.pdf] oil has become commercially accepted for power frequency applications. ([[Vegetable_Oil_Production |Canola oil]] is also a likely candidate for [[Hydraulic_Fluid |hydraulic fluid]].) Oil/paper may have dielectric loss factor ~1% (as opposed to polypropylene ~0.05%) so pay attention to internal heating.

===Melt Chamber===
# Geometical design of melt chamber and basic power transfer calculations
# Should include provisions for loading and pouring
# Given our goals, which is best: a coreless or a channel induction furnace type [http://www.wisegeek.com/what-is-an-induction-furnace.htm] ?
## channel: useful in the melting of lower melt temperature metals; less turbulence at the surface.
## coreless: stronger stirring, simpler crucible construction, most commonly used for induction scrap melting
# Pouring: manual pouring methods are more suited to low volume production lines.
====Crucible====
[[File:FirebrickTemps.png |thumb|Firebrick melting point vs Alumina:Silica composition]]
The crucible is made of refractory ceramic which resists the high temperatures of the melt. Even the best materials erode in use, and crucibles must be replaced on a regular basis. An induction furnace crucible may be either
# separately manufactured, fired in a kiln, and subsequently installed in the furnace, or
# formed in place, and sintered (fired) in the induction furnace itself

'''Materials'''

According to this [http://www.foseco.com/en-gb/end-markets/foundry/foseco-home-uk/ Foseco refractories] brochure[http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf], steel foundry induction-furnace applications typically use alumina or magnesia refractories, while cast-iron foundries use high purity silica. This is related to acid/base chemistry of the melt.

Fireclay (which can be a natural alumina/silica clay) for making refractory crucibles must withstand the superheated molten steel temperature of >3000F. Fireclay [http://www.mineralszone.com/minerals/fire-clay.html] is temperature-rated by Pyrometric Cone Equivalent (PCE) [http://www.ortonceramic.com/resources/reference/cone_ref.shtml]; "High Duty" (>= PCE32) or "Super Duty" (>= PCE35) is needed for ferrous metals. Such fireclay has high alumina content. (See also [[Aluminum_Extractor/Research_Development |Aluminum Extractor]] feedstock.)

Some worthwhile DIY fireclay/firebrick information [http://www.traditionaloven.com/articles/101/what-is-fire-clay-and-where-to-get-it here]

'''Separately made crucible'''
* See: [http://www.engineeredceramics.com/products/crucibles-and-ladles.html Engineered Ceramics Service Guides]
<html><iframe width="320" height="240" src="//www.youtube.com/embed/jEKjLSz1ATw?feature=player_embedded" frameborder="0" allowfullscreen></iframe></html>
* DIY small crucible video [http://www.youtube.com/watch?v=E3my6-nxFjM&feature=player_detailpage]<br>

'''Sintered-in-place crucible'''

The materials described in the [http://www.foseco.com/uploads/media/Furnace_Linings_Ferrous_01.pdf Foseco brocure] cited above are "dry-vibratable", meaning they are powders, rammed into place in situ, and sintered in the furnace itself, rather than being seperately made, kiln-fired crucibles. The refractory is rammed against a hollow steel internal ''former'' which defines the inside surface of the crucible. During the first power application, the former transfers sintering heat to the refractory, then either
* is melted away with the first heat leaving a fully-sintered lining[http://www.atlasfdry.com/inductionfurnaces.htm], or
* gets removed at a lower temperature, allowing re-use[http://www.dhanaprakash.com/product.php?nm=lp1&disc=ladleinductionfur.txt&type=Induction%20Furnace%20Removable%20Former%20Sintering&typeid=19&colorbg=6], with final sintering completed by gas flame before the first melting run

===Other Considerations===
# Complete bill of materials
# Fabrication files for circuit and other components
# Sourcing information for components
# System design and process flow drawings

==Notes==
===Benny===
I just read that you plan to build up an induction furnace. That´s a an interesting and exciting plan.While reading the article some remarks came to my mind.

But before I want to introduce myself:

I am Benny from Germany, Hannover.
I am diploma engineer for electrotechnology and working at the university. I am dealing with some induction heating/ melting applications like induction melting of glasses (that is possible!) and induction furnaces for cast iron.

Some remarks from my point of view:

# It is possible to build up a low cost furnace with the mentioned parameters.
# The frequency of 9,6 kHz is much to high. The efficiancy will be so bad, that it will be hardly possible to melt steel or iron. Due to the small penetration depth of about 2 mm with this frequency and this electrical resistance. So it needs a really small diameter of the crucible, and thats not helpful. Also the refractory material will be strained too much, so that a small lifetime is given. This will raise the cost for the operating.
# 50 Hz or 60 Hz is a better solution. And you can save the cost for the hf-converter.
# How much material do you want to cast at one time? The maximum, what i expect to be possible with 50 kW will be about 50 to 60 kg.
# What kind of raw material should be charged? It is important for the starting, because the initial density should not be too small (packing density). And the other question is, what kind of scrap it will be.
There are so many problems known with content of zinc (hot zinc dipped) and other materials. The lifetime of common refractory material is really small. And what is more important the security for the personal is not given without a strong exhaust system, due to the toxic steam. I expect this as a strong cost factor.

===Power Supply===
There are two approaches to providing the single-phase high-frequency AC power required by the induction furnace coil
* Electronic converter ([[Universal_Power_Supply |Universal Power Supply]])
** Wide frequency tunability possible - including very high frequencies for heat treating small parts
** Dynamic auto-tuning to coil resonance using established phase detector control methods
** power source: DC from [[Battery |battery]] storage banks
** power source: AC from 50/60Hz power
*** Typically the induction furnace power converter then operates AC->DC->AC
*** Preferably 3 phase AC source at higher power levels (better efficiency)
*** 50/60Hz AC can come from battery banks thru DC->AC converter, or from [[Generator |rotary generator]] driven by engine or hydraulic motor

* [[Generator |Rotary generator]]
** Limited frequency range
*** up to ~1kHz with slightly-modified conventional automotive alternator [http://www.venselenterprises.com/techtipsfromdick_files/alternators.pdf][http://www.delcoremy.com/Documents/Electrical-Specifications---Selection-Guide.aspx] (e.g. Delco 30SI 16 pole @ 10000 rpm = 1333Hz), perhaps adequate for crucible melting applications. [http://www.thebackshed.com/windmill/FPRewire.asp Fisher Paykel washing machine motors] are 48- or 56-pole permanent magnet designs often converted to generators and might operate into the low kilohertz range.
*** >100kHz historically feasible with [http://en.wikipedia.org/wiki/Alexanderson_alternator Alexanderson reluctance generators]
*** frequency controlled by varying shaft speed: frequency = shaft speed * pole pairs
*** dynamic auto-tuning to coil resonance may be difficult
** Three phase vs single phase
*** most reasonably-efficient rotary generators deliver balanced three-phase power, but an induction furnace is a single-phase load
*** this can be addressed with a simple tuned load balancer [http://www.google.com/patents/US3331909], but this may require manual tap- and capacitor adjustments depending on the load
*** alternatively a solid-state static synchronous compensator (STATCOM) can be applied, as described for example in [http://www.strutherstech.com/PDF/STATCOM%20LOAD%20BALANCING.pdf]
*** a combination of the above two methods (carrying most of the load unbalance with fixed capacitors/reactors and using a relatively low-VAR static compensator) might be most economical
** Mechanical power source
*** electric motor (motor-generator set)
*** prime mover (internal combustion or [[Steam_Engine |steam engine]])
*** hydraulic
**** [[Power_Cube |Power Cube]]
**** [[Stationary_Hydraulic_Power |Stationary hydraulic power]]
**** shaft speed control by variable displacement motor or [[Stationary_Hydraulic_Power#Hydraulic_pressure_transformation |hydraulic transformer]]

----
*50 kW for $1600 - [http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200415768835&rvr_id=&crlp=1_263602_263622&UA=L*F%3F&GUID=1357ab741250a0265337bec7ff94d6a7&itemid=200415768835&ff4=263602_263622]
*20 kw STC 3 phase 120 - 480V, also 1 phase - generator - $692 -[http://cgi.ebay.com/20kw-STC-3-Phase-277-480-12-Wire-generator-Head-altern_W0QQitemZ160369799644QQcmdZViewItemQQptZBI_Generators?hash=item2556c8f1dc]
*50 kw STC 3 phase- $1300 - [http://cgi.ebay.com/50KW-STC-3-Phase-12-Wire-generator-alternator_W0QQitemZ160357088416QQcmdZViewItemQQptZBI_Generators?hash=item255606fca0]
**LifeTrac 55 hp can produce 38 kW with this head

===Melt Calculations===
[[Image:inductioncalc.jpg]]

''Note:'' Electrical input requirements may be reduced somewhat by preheating the charge with flame or direct solar energy.

[[Image:imgp4545.jpg|600px]]

Photo I took while visiting a foundry near Santa Fe. Seems relevant!

==Wiki Links==

*[[Foundry]]

*[[Induction Furnace Request for Bids]]

==External Links==
* [http://blog.opensourceecology.org/?p=1373 Original Blog Post]
* [http://web.archive.org/web/20100816034057/http://www.uie.org/webfm_send/391 Technical basics and applications of induction furnace PDF]

==See Also==
{{Induction Furnace}}

[[Category:Induction_Furnace]]

Vegetable Oil Production

2014-04-05T22:43:17Z

ChuckH: /* Applications */

== Overview ==
OSE principles suggest minimal use of petroleum products, which often means the substitution of locally produced vegetable oils. Oil crops are also likely to be grown for edible cooking oils. In either case, appropriately-scaled oil processing technology is required.

== Applications ==

* Cooking oil
* [[Hydraulic_Fluid |Hydraulic fluid]]
* Motor fuel ([[Biodiesel]])
* Lubricating oil (e.g. [http://www.hort.purdue.edu/newcrop/proceedings1999/v4-247.html][http://www.hort.purdue.edu/newcrop/ncnu02/v5-029.html])
* Paints/coatings
* [[Induction_Furnace_Overview#Resonating_Capacitors |Electrical dielectric fluid]] (IEEE [[media:F03-EsterFluids.pdf | tutorial]])

== Crops ==

* Canola (modified rapeseed)[[http://www.hort.purdue.edu/newcrop/nexus/Brassica_rapeseed_nex.html]]
* Soybean
* Sunflower[http://www.hort.purdue.edu/newcrop/nexus/Helianthus_annuus_nex.html]
* Flax (Linseed)

== Processes ==
[[File:oilseed_refining.png |thumb]] [[File:Hydraulic_cage_press.png |thumb|An open-frame hydraulic cage press which could be re-implemented with the CEB]]
[http://www.cyberlipid.org/oilseed2008.pdf Small scale processing paper] from ATTRA

Oilseed pressing [http://www.appropedia.org/Original:Small_Scale_Vegetable_Oil_Extraction on Appropedia]

[http://science-in-farming.library4farming.org/Crops-Grains-Protein/OILSEEDS-OILS-AND-FATS.html at Library4Farming]

[http://www.rivendellvillage.org/oil_extraction.pdf from Practical Action]

Description of conventional Refined/Bleached/Deodorized(RBD) process in [http://www.freepatentsonline.com/20110204302.pdf this patent application]

The cage press method of expressing oil involves loading seed into a squeezing compartment, applying at least 500psi (higher pressures, up to thousands of psi, improve extraction efficiency) to crush seed and express the liquid oil, then removing the remaining solid oilcake. It seems that with appropriate simple modifications (a perforated pusher block above the moving press foot) the [[CEB_Press |CEB Press]] could perform this function very effectively.

[http://www.aseanfood.info/Articles/11023786.pdf Separating Oil from Aqueous Extraction Fractions of Soybean] examines the use of aqueous (basic) sodium hydroxide solutions for extraction of oil from soybeans processed with different means. A sodium hydroxide mixture is found to be 80-90% efficient but processing to lyse cells is key to a high yield. Lipid droplets are also complexed with lipid binding proteins (oleosin) which can complicate downstream processing.

[[Category: Food_and_Agriculture]]

File:F03-EsterFluids.pdf

2014-04-05T22:33:33Z

ChuckH:

PSoC Torch Height Sensing

2014-01-10T15:50:13Z

ChuckH: /* ChuckH testing */

= Cypress PSoC4 Pioneer Board for Capacitive Torch Height Sensing =

We are evaluating whether this board can provide operating height sensing for an oxyfuel torch and initial height sensing for a plasma torch. This is an [[Sensing_Distance_from_Work_Piece|important funtion]] required in the [[CNC Torch Table]].

The PSoc4 ("Programmable System on a Chip") is a small ARM microcontroller with flexible peripherals. One of the peripheral functions is Cypress' "CapSense" capacitive touch sensing. A relevant demo project, using the Arduino-form-factor "Pioneer" board is [http://www.element14.com/community/message/76985 here].

[[Image:ProximityDetection.jpg]]

== ChuckH testing ==
=== 10 Jan 2014 ===
Important note on PSoC4 capacitance sensing: must use PRS clock mode to avoid nonlinear "dead spots" in sigma-delta A to D conversion.
===12 August 2013===
Make 4-sector ring for testing.

[[Image:QuadRing.jpg|300px]]
===29 July 2013===
Current thoughts:
# Coil spring support (see 24-July pics) is nifty for tolerating side impacts, but it swivels too freely about its vertical axis. Maybe it's just too cute and we should use a solid piece of conduit instead.
# I am skeptical about the performance of the ring sensor over edges, holes, and anything else that is not a simple uniform plate of metal.
## Simple minded control would cause torch to dive down when approaching an edge or passing a cutout
## Logic could tell z-axis to "hold position" (i.e. stop tracking) if we know that an edge or gap is coming up, but this would require much more sophisticated and brittle CAM programming
## My preferred solution would be a 4-sector ring, and assuming that at least one sector will be over solid metal. There may still be corner cases missed by a "track Z by the closest sector reading" policy but not many.
## Most commercial cap-sense ICs are set up to handle lots of inputs (i.e. keypads) so this is only a ring-fabrication and wiring issue. Making the ring out of PC-board material sounds good.

===27 July 2013===
[[Image:Flatring500_150.png|thumb|0.05-in steps .50-.15-.50 in]]
Results from new flat aluminum sensing ring
# Signal is large, had to adjust PSoC A to D parameters to avoid overload
# Easily discriminates .050 inch steps, verified up to 0.5 inch standoff
# Loss of signal strength at edge of plate: 0.25 inch standoff over solid plate measures the same as 0.10 inch standoff centered over plate edge.

===24 July 2013===

Working on a new sensing ring featuring
# Made from sheet metal, the larger electrode area should provide more signal
# Coil spring mount
## Protects against accidental damage because it bends when hit but springs back to original position
## Coax signal line runs through hollow center of coil spring, providing a grounded secondary shield
## Wood split clamp provides electrical insulation for ring

[[Image:RingOnSpring.JPG|160px]] [[Image:ring_on_spring_test.jpg|480px]]

===21 July 2013===

We would like to place the circuit board in a shielded enclosure a foot or so from the torch itself, especially in the case of plasma torch application. Therefore I tried connecting the sensing electrode through about 2ft of coaxial cable. I used RG6/U type "CATV" coax (used with cable TV and antennas) because it is a foam core, low-capacitance cable, nominally ~16pf/ft. The PSoC chip supports "driven shield" so I used it. There are two subtypes of driven shield, "precharge by Vref buffer" and "precharge by IO buffer", it is not yet clear which is most appropriate.

To help protect the CapSense input pin from noise spikes (specifically a concern about plasma torch RF noise damaging the chip) I placed a 12pf capacitor in series with the sensing electrode. I made a ring shape out of insulated 14AWG solid house wiring:

[[Image:RingElectrode1.jpg|640px]]

[[Image:RingElectrode2.jpg|320px]]

Initial tests show plenty of signal close to the plate (the steps in this staircase are 0.050 inch movements), but sensitivity dropping off by 1/4" or so:

[[Image:full050steps.png]]

However the following technical issues need to be explored:
# Is the sensor adequately protected against plasma noise damage?
# How should the system reject long-term (time, temperature, etc.) drift?
# Will there be enough signal for oxyfuel cutting height tracking?
# Despite using shielded (coax), there is still some sensitivity to objects near the cable and circuit board.
# How will the system respond to sensing near the edge of a workpiece (where only half of the ring is over the work)? An informal check showed significant signal loss.

In addition we have to develop code which uses the distance sensing information to control a z-axis motor. This could run on the RAMPS Arduino, or it would be possible to execute this code on the PSoC4 Pioneer board; it has a pretty capable microprocessor. For that matter, the PSoC could also handle arc voltage sensing for a plasma torch.

Chuck Log

2013-09-06T00:04:03Z

ChuckH: /* Current Log */

= Intro =
A chronological log for [[Chuck_Harrison|Chuck Harrison]], occasional off-site collaborator.

= Current Log =
== 2-Sep-2013 thru 8-Sep-2013 ==
progress on [http://wiki.jigren.org/index.php?title=Rosserial_On_Cypress_PSoC4 PSoC4 ROS]

contemplating dye-LED-webcam-based pH sensor for [[Lab_Scale_Fermentor#pH_sensing]]

== 26-Aug-2013 thru 1-Sep-2013 ==
Met people from local (Seattle) biohacker space starting up: http://hivebio.org/ . Getting started on [[Lab_Scale_Fermentor]] for polylactic acid, contacted Eric Poliner.

Bringing up ROS environment on PSoC4 board. [http://wiki.jigren.org/index.php?title=Rosserial_On_Cypress_PSoC4]. ROS is potentially a good communications protocol for distributed modular control systems. [[Distributed_CNC_Motion_Control]]

Measured thermal behavior of lab scale fermentor with a bunch of thermocouples: [[Lab_Scale_Fermentor#Thermal_Characterization]]

== 12-Aug-2013 thru 18-Aug-2013 ==
CNC Torch Table - automatic gas controller - [[CNC_Torch_Table_Control_Overview#Oxyfuel_.28oxyacetylene.2C_oxypropane.2C_etc.29_cutting_torch]]

[[Paul_Log#AD7747_vs_PSoC4|Brief comparison AD7747 vs PSoC4 capsense]].

Made [[PSoC_Torch_Height_Sensing#12_August_2013|Quad sector sense ring]] for testing from perf board.

Started wiki page [[Distributed_CNC_Motion_Control]]

== 05-Aug-2013 thru 11-Aug-2013 ==
See [[Torch Height Controller Discussions]].
== 29-Jul-2013 thru 04-Aug-2013 ==
[[PSoC_Torch_Height_Sensing#29_July_2013|PSoC4 capsense torch height sensor]]. Worried about oxyfuel torch height control when traveling near or over edges and holes.
== 22-Jul-2013 thru 28-Jul-2013 ==
[[PSoC_Torch_Height_Sensing#27_July_2013|PSoC4 capsense torch height sensor]]. Flat aluminum ring has much more capacitance, good range. Try coil spring mount but it twists too easily.
== 15-Jul-2013 thru 21-Jul-2013 ==
[[PSoC_Torch_Height_Sensing#21_July_2013|PSoC4 capsense torch height sensor]] initial testing with 14AWG insulated wire sense ring; not enough range.

Description and proof-of-concept video for Arduino-controlled proportioning gas pressure control. See [[CNC_Torch_Table_Control_Overview#Oxyfuel_.28oxyacetylene.2C_oxypropane.2C_etc.29_cutting_torch|Torch Table Control Overview]]

== 21-Jan-2013 thru 28-Jan-2013 ==
* exercised extopenSCAD->svg->eps->TorchmateCAD->dxf->gcode [[TorchTableTraining#CAD_toolchain|toolchain]] on Torchmate table, still buggy.
* installed Si8600 I2C isolator in [[CNC_Torch_Table_Control_Overview#Steppernug_Driver_and_Interface|Steppernug v1_1 interface]], added Arduino-side pullups, functional test ok.

== 31-Dec-2012 thru 6-Jan-2013 ==
* implicitCAD hierarchical design with gnu make and cpp [[TorchTableToolChainTesting#implicitCAD_hierarchical_design]]

= 2012 Log =
== 24-Dec-2012 thru 30-Dec-2012 ==
* tested implicitCAD svg export; sent patch to developers
* emailed Chris Struthers about STATCOM load balancing for [[Induction_Furnace_Overview#Power_Supply|Induction Furnace with rotary generator]]
== 16-Dec-2012 thru 23-Dec-2012 ==
* More grbl testing & code update [[Stepper_Testing#timing]]
* Got a g-code sender program working on Raspberry Pi [[GcodeCommunications#Universal_G-code_Sender_on_Raspberry_Pi]]
== 8-Dec-2012 thru 15-Dec-2012 ==
* Update I2C code in grbl [https://github.com/chuck-h/grbl/issues/4#issuecomment-11278387]
* Test some [[TorchTableTraining#Fold_patterns|plasma cuts]] for angle fold-ups
* Pulled implicitCAD commit 1c4ac855338 from github, merged Windows patches, built painlessly! [[TorchTableToolChainTesting#Tool_chain_experiments_for_Torch_Table_programming|plasma gcode generation]] is getting closer.

== 1-Dec-2012 thru 7-Dec-2012 ==
* [[TorchTableToolChainTesting#Tool_chain_experiments_for_Torch_Table_programming|Torch toolchain with implicitCAD]]. Need to clean up multi-segment implicitCAD svg's for g-code.
* Received ebay valves that may be useful for an oxyfuel torch
* Change of plan: do plasma cutting off site, relax deadline pressure on torch table construction. Urgent task to update CEB drawings for Dec 18 build [[Hopper_Work_Statement]] - individual part drawings completed.
* [[TorchTableToolChainTesting#Alibre_-.3E_DXF_toolchain|Alibre toolchain]]
* Created github repository for hopper work [https://github.com/chuck-h/ose-cebpress-hopper here], unfortunately Marcin and Kavitha seem to have difficulty using it.
* Worked on concept for interchangeable touch-probe & marking device for torch table.

== 25-Nov-2012 thru 31-Nov-2012 ==
* got update from FEF regarding Dec 18 CEB build: no oxyfuel, using PP60 plasma on torch table, new tool chain with ImplicitCAD
* download ImplicitCAD to my laptop, limited functionality on Windows, see [http://christopherolah.wordpress.com/2012/02/06/implicitcad-0-0-1-release/#comment-923 here]
* first [[TorchTableTraining|training session]] with Rusty's Torchmate CNC Plasma cutter.
* visited Steve Hussey at Burning Specialties, a company that does CNC and pattern-follower oxypropane cutting with a huge older cantilever machine. Nice guy.

== 18-Nov-2012 thru 24-Nov-2012 ==
* sync grbl to [https://github.com/grbl/grbl/commit/5dd6d90122dce991a99eab5aa3a5c991dd5c938a upstream]..success.
* replaced mechanical microswitches on X1-X2 axis with photointerrupters..success. [[Stepper_Testing#opto|Testing]]
* contact Kavitha to coordinate torch table prep for Dec. 18 CEB build.
* research CNC oxyfuel torch cutting [[CNC_Torch_Table#Cutting_Torch]]
* research onsite oxygen generation (PSA)
* order some gas valves off eBay

== 11-Nov-2012 thru 17-Nov-2012 ==
* start log.
* ship Millermatic 200 welder (Seattle craigslist) by LTL truck to FEF. 400 lbs for $500; was that reasonable?
* [[OSE_Open_Source_Stepper_Motor_Controller|steppernug]] (open source stepper driver) schematic review with Darren
* received [http://www.mouser.com/ProductDetail/Sharp-Microelectronics/GP1A75EJ000F/?qs=%2fha2pyFaduhmXejJv184BikaBEqZykWweNnmsglkeuWVbMieAKIiNg%3d%3d photointerrupters] for torch table testing
* looking into "does not quite reach position" bug in my grbl branch

== Ancient history ==

First contact with OSE Sept 2011 briefly on site. I was in the area visiting relatives David Ihnen and Margaret Havens.

[[Category:Personal Logs]]

Lab Scale Fermentor

2013-09-05T23:59:16Z

ChuckH: /* pH sensing */

= Lab Scale Fermentor =

This is a version of the [[Fermentor#System_Engineering_Breakdown_Diagram|OSE Fermentor]] primarily for process-development experiments.

It may be used on the [[Polylactic acid]] project.

== Prototype Development ==

I have acquired some components and will report here on construction progress of a low-cost "lab scale" (~1 liter) microbe fermentor. [[User:ChuckH|ChuckH]] ([[User talk:ChuckH|talk]]) 04:48, 29 August 2013 (CEST)

=== Chamber ===

Our basic chamber is a small consumer slow cooker ("crock pot"). This unit ([http://www.proctorsilex.com/products/slow-cookers-15-quart-slow-cooker-model-33116y.php Proctor Silex 33116Y]) has a glass lid with a soft rubber lip seal and costs about $15.

[[File:slowcooker_1.jpg|border|250px]] [[File:slowcooker_lidgasket.jpg|border|200px]]
----
The lid is made of glass. It appears ''not'' to be tempered, as the handle is attached by a screw through a drilled hole. This is good, because it means we can drill our own holes for stirring, sensors, and fluid lines. I will try using some cheap diamond core drills (the set shown cost $5 on Amazon).

[[File:slowcooker_lid_holes.jpg|border|300px]]
----
The heating jacket is a light-gauge aluminum bowl with a band heater around it. The heater has two elements, measuring 477 ohms and 200 ohms. The front-panel switch selects element 1, element 2, or both in parallel, providing 28W, 66W, and 94W respectively at 115V input. There is no thermostat.

[[File:slowcooker_internal2.jpg|border|300px]] [[File:slowcooker_internal_1.jpg|border|300px]]

It should be possible to control temperature with an arduino, thermistor, and solid-state relay, without any modification to the internals.

=== Thermal Characterization ===

In order to establish expectations and initial control parameters for the temperature control algorithm, we measured the heating performance of the chamber filled with water. The behavior is somewhat nonlinear, and has two significant thermal masses with different thermal time constants. Nonetheless, a reasonable single-time-constant linear model approximation can be obtained. Ambient temperature was ~30C. Initial fluid temperature was ~25C.

The thermal time constant is estimated at 120 minutes, and the temperature rise rate at the "HIGH" setting corresponds to an ultimate temperature of ~80C above ambient.

[[File:slowcooker_thermal_plot.png|border|300px]] [[File:slowcooker_thermal_plot_full.png|border|280px]]

Spreadsheet: [[File:ThermalCharacterization.ods]]

{| class="wikitable"
|+Thermocouple locations
|-
| TC1 || Heating jacket, near heating element
|-
| TC2 || Heating jacket, center bottom
|-
| TC3 || Bowl, outside, near middle height
|-
| TC4 || Bowl, inside, aligned with TC3
|-
| TC5 || Water, ~4mm off bottom, centered
|-
| TC6 || Water, ~6mm immersed, off-center
|}

The lid steams up at higher temperatures, might interfere with observations.

<html>
<script type="text/javascript" src="http://s3.www.universalsubtitles.org/embed.js">
(
{"video_url": "http://www.youtube.com/watch/?v=cNEioVxZ6zs"}
)
</script>
</html>

=== pH sensing ===

colorimetric sensing of gel-stabilized phenol red indicator seems hopeful. The dye is readily available at low cost as a [http://www.hydropool.com/cgi-bin/hydro/item/Water-Testing/Phenol-Red-1-oz-Reagant-Refill/26242.html pool test chemical]. Differential optical absorption measurement between the violet-absorption and green-absorption peaks can be converted into a pH reading. Unfortunately the dye absorption peaks don't line up ideally with typical digital camera color filters:

[[File:phenol_red_OV7949.png|300px)]]

Alternating illumination with appropriate LEDs, using a USB webcam and a split field of view between inactive reference reflector and dye-loaded gel could work. Try [http://www.ebay.com/itm/Agarose-50-grams-Low-EEO-Molecular-Biology-Grade-DNA-RNA-Electrophoresis-1-/130944677475?pt=LH_DefaultDomain_0&hash=item1e7ce93663 agarose] for gel.

Lab Scale Fermentor

2013-09-05T23:50:15Z

ChuckH: /* Prototype Development */

File:Phenol red OV7949.png

2013-09-05T23:38:38Z

ChuckH:

Distributed CNC Motion Control

2013-09-03T03:13:26Z

ChuckH: /* OSE Implementation */

= Centralized Motion Control =

CNC tools like the [[CNC Torch Table]], [[HydraFabber]], etc. require precision synchronized multi-axis movement. Typically a central controller, such as [[CoolRAMPS]] or [[Steppernug]], has the responsibility of generating synchronized step-and-direction commands on three axes, with rates up to about 20,000 pulses per second. As more axes and auxiliary functions are added to the machine, the hardware resources and software coordination required to maintain "hard real time" performance in the single central controller become a bottleneck.

= Distributed Motion Control Concept =

Distributed motion control, in contrast to centralized control, supports a modular design process in which new functions can be added with additional loosely-coupled processors, rather than being knitted into a single program. Modularity is appropriate for OSE designs.

== Communication and OS Latency ==

Loosely-coupled processors receive ''commands'' and report ''status'' over communications links. In practice, it is difficult to obtain the low latency and low jitter (latency variation) required to simply pass motion commands in real time, just in time to be executed. Furthermore, low-cost serial communication channels have a limited bandwidth.

Similar latency and jitter issues arise when a complex operating system (such as Linux or Windows) is used to generate multi-axis motion commands through multiple threads or processes.

An overall scheme to achieve precise coordination in the face of variable latency is needed in order to make distributed motion control feasible. In general, this means that commands are prepared a little bit ahead of when they are needed, and stored in a buffer at the receiving end.

In CNC applications, we know the required motion pattern in precise detail before the work cycle begins. In principle, adding buffers and latency simply delays the execution of the pre-programmed path by a small amount. However, it is important to consider every machine behavior which is ''not'' pre-programmed, and how it is impacted by latency. For example,
* The operator hits "stop" on a control panel.
* The machine uses a touch probe to locate a feature of the workpiece.
* The operator interactively increases or decreases the cutting speed.
* A fault condition occurs.

== Trajectory command distribution ==

CNC machines are most commonly programmed in ''[[G-code]]''. Each "motion" line of a G-code program specifies a coordinated move of the entire machine (3, 4, or more axes), telling it to arrive at a target endpoint following a particular trajectory. Often the trajectory is simply a straight line, but there are standard G-code commands for circles, partial arcs, and helices.

In a distributed system, where (for example) one processor handles X,Y,Z motions of a milling machine frame and a different processor handles a "4th axis" rotary table, it is not enough to simply send the target endpoint information to the rotary-table processor. It must also know when to start moving, how fast to accelerate, and a few other parameters in order to assure its movement is precisely coordinated with the machine frame at every point in the move. The process of breaking up a single G-code motion command into individual axis commands for distribution to loosely-coupled motion processors can become somewhat tricky and bandwidth-intensive. Furthermore, there is no "industry standard" format for these distributed commands that is comparable to G-code itself.

== Synchronizing command execution ==

When commands arrive through a variable-latency buffered communications path, an "execute on arrival" policy won't work. The execution of the commands must be ''scheduled'' by some mechanism relying on each receiving processor's local timebase. Furthermore, it is necessary to synchronize the distributed processors continuously so that they do not drift over time. A CNC may take hours to complete the motions required to shape a part, and a drift of less than 100 microseconds between axes could cause a measurable dimensional error in the part.

== Relation between CNC and Robotic Control ==

Robotic control, like CNC machine tool control, involves coordinated movement of several axes. Robot design and programming techniques can be considered in the CNC world, keeping in mind the different emphasis in these two disciplines:
# Robots tend to have large numbers of actuation axes compared to simple machine tools
# Robots tend to have lesser requirements for precision ''during'' a move, even if they must arrive precisely at a final position
# Robots often expect ''feedback'' from their environment, causing them to dynamically alter trajectories. Unlike "canned" CNC programs, interactive systems do not tolerate latency well.

= OSE Implementation =

How to implement distributed CNC machine control in accordance with OSE principles...

(Possible techniques, to be expanded)

* [http://www.ros.org/wiki/ ROS] (robot operating system) framework [http://opensourceecology.org/wiki/Industrial_Robot/Research_Development#Other_2]
* Shop-wide communications [http://wiki.ros.org/sig/Multimaster ROS Multimaster]
* [http://www.orocos.org/ Orocos] realtime software in nodes if appropriate
* Distributed motion commands as PVT (position, velocity, time) messages
** semantics: "starting where you are now, at your current instantaneous velocity, arrive at absolute position P at absolute time T, moving at instantaneous velocity V when you arrive"
** usually implies cubic-spline interpolator
* Lookahead trajectory planner to process G-code (see grbl? [http://wiki.linuxcnc.org/cgi-bin/wiki.pl?List_Of_CAM_References LinuxCNC CAM references]?)
** convert line and arc G-codes to PVT
** coalesce adjacent commands if accuracy isn't compromised (reduces PVT command rate)

Chuck Log

2013-09-03T03:08:41Z

ChuckH: /* 2-Sep-2013 thru 8-Sep-2013 */

= Intro =
A chronological log for [[Chuck_Harrison|Chuck Harrison]], occasional off-site collaborator.

= Current Log =
== 2-Sep-2013 thru 8-Sep-2013 ==
progress on [http://wiki.jigren.org/index.php?title=Rosserial_On_Cypress_PSoC4 PSoC4 ROS]

== 26-Aug-2013 thru 1-Sep-2013 ==
Met people from local (Seattle) biohacker space starting up: http://hivebio.org/ . Getting started on [[Lab_Scale_Fermentor]] for polylactic acid, contacted Eric Poliner.

Bringing up ROS environment on PSoC4 board. [http://wiki.jigren.org/index.php?title=Rosserial_On_Cypress_PSoC4]. ROS is potentially a good communications protocol for distributed modular control systems. [[Distributed_CNC_Motion_Control]]

Measured thermal behavior of lab scale fermentor with a bunch of thermocouples: [[Lab_Scale_Fermentor#Thermal_Characterization]]

== 12-Aug-2013 thru 18-Aug-2013 ==
CNC Torch Table - automatic gas controller - [[CNC_Torch_Table_Control_Overview#Oxyfuel_.28oxyacetylene.2C_oxypropane.2C_etc.29_cutting_torch]]

[[Paul_Log#AD7747_vs_PSoC4|Brief comparison AD7747 vs PSoC4 capsense]].

Made [[PSoC_Torch_Height_Sensing#12_August_2013|Quad sector sense ring]] for testing from perf board.

Started wiki page [[Distributed_CNC_Motion_Control]]

== 05-Aug-2013 thru 11-Aug-2013 ==
See [[Torch Height Controller Discussions]].
== 29-Jul-2013 thru 04-Aug-2013 ==
[[PSoC_Torch_Height_Sensing#29_July_2013|PSoC4 capsense torch height sensor]]. Worried about oxyfuel torch height control when traveling near or over edges and holes.
== 22-Jul-2013 thru 28-Jul-2013 ==
[[PSoC_Torch_Height_Sensing#27_July_2013|PSoC4 capsense torch height sensor]]. Flat aluminum ring has much more capacitance, good range. Try coil spring mount but it twists too easily.
== 15-Jul-2013 thru 21-Jul-2013 ==
[[PSoC_Torch_Height_Sensing#21_July_2013|PSoC4 capsense torch height sensor]] initial testing with 14AWG insulated wire sense ring; not enough range.

Description and proof-of-concept video for Arduino-controlled proportioning gas pressure control. See [[CNC_Torch_Table_Control_Overview#Oxyfuel_.28oxyacetylene.2C_oxypropane.2C_etc.29_cutting_torch|Torch Table Control Overview]]

== 21-Jan-2013 thru 28-Jan-2013 ==
* exercised extopenSCAD->svg->eps->TorchmateCAD->dxf->gcode [[TorchTableTraining#CAD_toolchain|toolchain]] on Torchmate table, still buggy.
* installed Si8600 I2C isolator in [[CNC_Torch_Table_Control_Overview#Steppernug_Driver_and_Interface|Steppernug v1_1 interface]], added Arduino-side pullups, functional test ok.

== 31-Dec-2012 thru 6-Jan-2013 ==
* implicitCAD hierarchical design with gnu make and cpp [[TorchTableToolChainTesting#implicitCAD_hierarchical_design]]

= 2012 Log =
== 24-Dec-2012 thru 30-Dec-2012 ==
* tested implicitCAD svg export; sent patch to developers
* emailed Chris Struthers about STATCOM load balancing for [[Induction_Furnace_Overview#Power_Supply|Induction Furnace with rotary generator]]
== 16-Dec-2012 thru 23-Dec-2012 ==
* More grbl testing & code update [[Stepper_Testing#timing]]
* Got a g-code sender program working on Raspberry Pi [[GcodeCommunications#Universal_G-code_Sender_on_Raspberry_Pi]]
== 8-Dec-2012 thru 15-Dec-2012 ==
* Update I2C code in grbl [https://github.com/chuck-h/grbl/issues/4#issuecomment-11278387]
* Test some [[TorchTableTraining#Fold_patterns|plasma cuts]] for angle fold-ups
* Pulled implicitCAD commit 1c4ac855338 from github, merged Windows patches, built painlessly! [[TorchTableToolChainTesting#Tool_chain_experiments_for_Torch_Table_programming|plasma gcode generation]] is getting closer.

== 1-Dec-2012 thru 7-Dec-2012 ==
* [[TorchTableToolChainTesting#Tool_chain_experiments_for_Torch_Table_programming|Torch toolchain with implicitCAD]]. Need to clean up multi-segment implicitCAD svg's for g-code.
* Received ebay valves that may be useful for an oxyfuel torch
* Change of plan: do plasma cutting off site, relax deadline pressure on torch table construction. Urgent task to update CEB drawings for Dec 18 build [[Hopper_Work_Statement]] - individual part drawings completed.
* [[TorchTableToolChainTesting#Alibre_-.3E_DXF_toolchain|Alibre toolchain]]
* Created github repository for hopper work [https://github.com/chuck-h/ose-cebpress-hopper here], unfortunately Marcin and Kavitha seem to have difficulty using it.
* Worked on concept for interchangeable touch-probe & marking device for torch table.

== 25-Nov-2012 thru 31-Nov-2012 ==
* got update from FEF regarding Dec 18 CEB build: no oxyfuel, using PP60 plasma on torch table, new tool chain with ImplicitCAD
* download ImplicitCAD to my laptop, limited functionality on Windows, see [http://christopherolah.wordpress.com/2012/02/06/implicitcad-0-0-1-release/#comment-923 here]
* first [[TorchTableTraining|training session]] with Rusty's Torchmate CNC Plasma cutter.
* visited Steve Hussey at Burning Specialties, a company that does CNC and pattern-follower oxypropane cutting with a huge older cantilever machine. Nice guy.

== 18-Nov-2012 thru 24-Nov-2012 ==
* sync grbl to [https://github.com/grbl/grbl/commit/5dd6d90122dce991a99eab5aa3a5c991dd5c938a upstream]..success.
* replaced mechanical microswitches on X1-X2 axis with photointerrupters..success. [[Stepper_Testing#opto|Testing]]
* contact Kavitha to coordinate torch table prep for Dec. 18 CEB build.
* research CNC oxyfuel torch cutting [[CNC_Torch_Table#Cutting_Torch]]
* research onsite oxygen generation (PSA)
* order some gas valves off eBay

== 11-Nov-2012 thru 17-Nov-2012 ==
* start log.
* ship Millermatic 200 welder (Seattle craigslist) by LTL truck to FEF. 400 lbs for $500; was that reasonable?
* [[OSE_Open_Source_Stepper_Motor_Controller|steppernug]] (open source stepper driver) schematic review with Darren
* received [http://www.mouser.com/ProductDetail/Sharp-Microelectronics/GP1A75EJ000F/?qs=%2fha2pyFaduhmXejJv184BikaBEqZykWweNnmsglkeuWVbMieAKIiNg%3d%3d photointerrupters] for torch table testing
* looking into "does not quite reach position" bug in my grbl branch

== Ancient history ==

First contact with OSE Sept 2011 briefly on site. I was in the area visiting relatives David Ihnen and Margaret Havens.

[[Category:Personal Logs]]

Chuck Log

2013-09-03T03:08:07Z

ChuckH: /* Current Log */

= Intro =
A chronological log for [[Chuck_Harrison|Chuck Harrison]], occasional off-site collaborator.

= Current Log =
== 2-Sep-2013 thru 8-Sep-2013 ==
progress on [http://wiki.jigren.org/index.php?title=Rosserial_On_Cypress_PSoC4|PSoC4 ROS]
== 26-Aug-2013 thru 1-Sep-2013 ==
Met people from local (Seattle) biohacker space starting up: http://hivebio.org/ . Getting started on [[Lab_Scale_Fermentor]] for polylactic acid, contacted Eric Poliner.

Bringing up ROS environment on PSoC4 board. [http://wiki.jigren.org/index.php?title=Rosserial_On_Cypress_PSoC4]. ROS is potentially a good communications protocol for distributed modular control systems. [[Distributed_CNC_Motion_Control]]

Measured thermal behavior of lab scale fermentor with a bunch of thermocouples: [[Lab_Scale_Fermentor#Thermal_Characterization]]

== 12-Aug-2013 thru 18-Aug-2013 ==
CNC Torch Table - automatic gas controller - [[CNC_Torch_Table_Control_Overview#Oxyfuel_.28oxyacetylene.2C_oxypropane.2C_etc.29_cutting_torch]]

[[Paul_Log#AD7747_vs_PSoC4|Brief comparison AD7747 vs PSoC4 capsense]].

Made [[PSoC_Torch_Height_Sensing#12_August_2013|Quad sector sense ring]] for testing from perf board.

Started wiki page [[Distributed_CNC_Motion_Control]]

== 05-Aug-2013 thru 11-Aug-2013 ==
See [[Torch Height Controller Discussions]].
== 29-Jul-2013 thru 04-Aug-2013 ==
[[PSoC_Torch_Height_Sensing#29_July_2013|PSoC4 capsense torch height sensor]]. Worried about oxyfuel torch height control when traveling near or over edges and holes.
== 22-Jul-2013 thru 28-Jul-2013 ==
[[PSoC_Torch_Height_Sensing#27_July_2013|PSoC4 capsense torch height sensor]]. Flat aluminum ring has much more capacitance, good range. Try coil spring mount but it twists too easily.
== 15-Jul-2013 thru 21-Jul-2013 ==
[[PSoC_Torch_Height_Sensing#21_July_2013|PSoC4 capsense torch height sensor]] initial testing with 14AWG insulated wire sense ring; not enough range.

Description and proof-of-concept video for Arduino-controlled proportioning gas pressure control. See [[CNC_Torch_Table_Control_Overview#Oxyfuel_.28oxyacetylene.2C_oxypropane.2C_etc.29_cutting_torch|Torch Table Control Overview]]

== 21-Jan-2013 thru 28-Jan-2013 ==
* exercised extopenSCAD->svg->eps->TorchmateCAD->dxf->gcode [[TorchTableTraining#CAD_toolchain|toolchain]] on Torchmate table, still buggy.
* installed Si8600 I2C isolator in [[CNC_Torch_Table_Control_Overview#Steppernug_Driver_and_Interface|Steppernug v1_1 interface]], added Arduino-side pullups, functional test ok.

== 31-Dec-2012 thru 6-Jan-2013 ==
* implicitCAD hierarchical design with gnu make and cpp [[TorchTableToolChainTesting#implicitCAD_hierarchical_design]]

= 2012 Log =
== 24-Dec-2012 thru 30-Dec-2012 ==
* tested implicitCAD svg export; sent patch to developers
* emailed Chris Struthers about STATCOM load balancing for [[Induction_Furnace_Overview#Power_Supply|Induction Furnace with rotary generator]]
== 16-Dec-2012 thru 23-Dec-2012 ==
* More grbl testing & code update [[Stepper_Testing#timing]]
* Got a g-code sender program working on Raspberry Pi [[GcodeCommunications#Universal_G-code_Sender_on_Raspberry_Pi]]
== 8-Dec-2012 thru 15-Dec-2012 ==
* Update I2C code in grbl [https://github.com/chuck-h/grbl/issues/4#issuecomment-11278387]
* Test some [[TorchTableTraining#Fold_patterns|plasma cuts]] for angle fold-ups
* Pulled implicitCAD commit 1c4ac855338 from github, merged Windows patches, built painlessly! [[TorchTableToolChainTesting#Tool_chain_experiments_for_Torch_Table_programming|plasma gcode generation]] is getting closer.

== 1-Dec-2012 thru 7-Dec-2012 ==
* [[TorchTableToolChainTesting#Tool_chain_experiments_for_Torch_Table_programming|Torch toolchain with implicitCAD]]. Need to clean up multi-segment implicitCAD svg's for g-code.
* Received ebay valves that may be useful for an oxyfuel torch
* Change of plan: do plasma cutting off site, relax deadline pressure on torch table construction. Urgent task to update CEB drawings for Dec 18 build [[Hopper_Work_Statement]] - individual part drawings completed.
* [[TorchTableToolChainTesting#Alibre_-.3E_DXF_toolchain|Alibre toolchain]]
* Created github repository for hopper work [https://github.com/chuck-h/ose-cebpress-hopper here], unfortunately Marcin and Kavitha seem to have difficulty using it.
* Worked on concept for interchangeable touch-probe & marking device for torch table.

== 25-Nov-2012 thru 31-Nov-2012 ==
* got update from FEF regarding Dec 18 CEB build: no oxyfuel, using PP60 plasma on torch table, new tool chain with ImplicitCAD
* download ImplicitCAD to my laptop, limited functionality on Windows, see [http://christopherolah.wordpress.com/2012/02/06/implicitcad-0-0-1-release/#comment-923 here]
* first [[TorchTableTraining|training session]] with Rusty's Torchmate CNC Plasma cutter.
* visited Steve Hussey at Burning Specialties, a company that does CNC and pattern-follower oxypropane cutting with a huge older cantilever machine. Nice guy.

== 18-Nov-2012 thru 24-Nov-2012 ==
* sync grbl to [https://github.com/grbl/grbl/commit/5dd6d90122dce991a99eab5aa3a5c991dd5c938a upstream]..success.
* replaced mechanical microswitches on X1-X2 axis with photointerrupters..success. [[Stepper_Testing#opto|Testing]]
* contact Kavitha to coordinate torch table prep for Dec. 18 CEB build.
* research CNC oxyfuel torch cutting [[CNC_Torch_Table#Cutting_Torch]]
* research onsite oxygen generation (PSA)
* order some gas valves off eBay

== 11-Nov-2012 thru 17-Nov-2012 ==
* start log.
* ship Millermatic 200 welder (Seattle craigslist) by LTL truck to FEF. 400 lbs for $500; was that reasonable?
* [[OSE_Open_Source_Stepper_Motor_Controller|steppernug]] (open source stepper driver) schematic review with Darren
* received [http://www.mouser.com/ProductDetail/Sharp-Microelectronics/GP1A75EJ000F/?qs=%2fha2pyFaduhmXejJv184BikaBEqZykWweNnmsglkeuWVbMieAKIiNg%3d%3d photointerrupters] for torch table testing
* looking into "does not quite reach position" bug in my grbl branch

== Ancient history ==

First contact with OSE Sept 2011 briefly on site. I was in the area visiting relatives David Ihnen and Margaret Havens.

[[Category:Personal Logs]]

Chuck Log

2013-09-02T07:13:46Z

ChuckH: /* 26-Aug-2013 thru 1-Sep-2013 */

= Intro =
A chronological log for [[Chuck_Harrison|Chuck Harrison]], occasional off-site collaborator.

= Current Log =
== 26-Aug-2013 thru 1-Sep-2013 ==
Met people from local (Seattle) biohacker space starting up: http://hivebio.org/ . Getting started on [[Lab_Scale_Fermentor]] for polylactic acid, contacted Eric Poliner.

Bringing up ROS environment on PSoC4 board. [http://wiki.jigren.org/index.php?title=Rosserial_On_Cypress_PSoC4]. ROS is potentially a good communications protocol for distributed modular control systems. [[Distributed_CNC_Motion_Control]]

Measured thermal behavior of lab scale fermentor with a bunch of thermocouples: [[Lab_Scale_Fermentor#Thermal_Characterization]]

== 12-Aug-2013 thru 18-Aug-2013 ==
CNC Torch Table - automatic gas controller - [[CNC_Torch_Table_Control_Overview#Oxyfuel_.28oxyacetylene.2C_oxypropane.2C_etc.29_cutting_torch]]

[[Paul_Log#AD7747_vs_PSoC4|Brief comparison AD7747 vs PSoC4 capsense]].

Made [[PSoC_Torch_Height_Sensing#12_August_2013|Quad sector sense ring]] for testing from perf board.

Started wiki page [[Distributed_CNC_Motion_Control]]

== 05-Aug-2013 thru 11-Aug-2013 ==
See [[Torch Height Controller Discussions]].
== 29-Jul-2013 thru 04-Aug-2013 ==
[[PSoC_Torch_Height_Sensing#29_July_2013|PSoC4 capsense torch height sensor]]. Worried about oxyfuel torch height control when traveling near or over edges and holes.
== 22-Jul-2013 thru 28-Jul-2013 ==
[[PSoC_Torch_Height_Sensing#27_July_2013|PSoC4 capsense torch height sensor]]. Flat aluminum ring has much more capacitance, good range. Try coil spring mount but it twists too easily.
== 15-Jul-2013 thru 21-Jul-2013 ==
[[PSoC_Torch_Height_Sensing#21_July_2013|PSoC4 capsense torch height sensor]] initial testing with 14AWG insulated wire sense ring; not enough range.

Description and proof-of-concept video for Arduino-controlled proportioning gas pressure control. See [[CNC_Torch_Table_Control_Overview#Oxyfuel_.28oxyacetylene.2C_oxypropane.2C_etc.29_cutting_torch|Torch Table Control Overview]]

== 21-Jan-2013 thru 28-Jan-2013 ==
* exercised extopenSCAD->svg->eps->TorchmateCAD->dxf->gcode [[TorchTableTraining#CAD_toolchain|toolchain]] on Torchmate table, still buggy.
* installed Si8600 I2C isolator in [[CNC_Torch_Table_Control_Overview#Steppernug_Driver_and_Interface|Steppernug v1_1 interface]], added Arduino-side pullups, functional test ok.

== 31-Dec-2012 thru 6-Jan-2013 ==
* implicitCAD hierarchical design with gnu make and cpp [[TorchTableToolChainTesting#implicitCAD_hierarchical_design]]

= 2012 Log =
== 24-Dec-2012 thru 30-Dec-2012 ==
* tested implicitCAD svg export; sent patch to developers
* emailed Chris Struthers about STATCOM load balancing for [[Induction_Furnace_Overview#Power_Supply|Induction Furnace with rotary generator]]
== 16-Dec-2012 thru 23-Dec-2012 ==
* More grbl testing & code update [[Stepper_Testing#timing]]
* Got a g-code sender program working on Raspberry Pi [[GcodeCommunications#Universal_G-code_Sender_on_Raspberry_Pi]]
== 8-Dec-2012 thru 15-Dec-2012 ==
* Update I2C code in grbl [https://github.com/chuck-h/grbl/issues/4#issuecomment-11278387]
* Test some [[TorchTableTraining#Fold_patterns|plasma cuts]] for angle fold-ups
* Pulled implicitCAD commit 1c4ac855338 from github, merged Windows patches, built painlessly! [[TorchTableToolChainTesting#Tool_chain_experiments_for_Torch_Table_programming|plasma gcode generation]] is getting closer.

== 1-Dec-2012 thru 7-Dec-2012 ==
* [[TorchTableToolChainTesting#Tool_chain_experiments_for_Torch_Table_programming|Torch toolchain with implicitCAD]]. Need to clean up multi-segment implicitCAD svg's for g-code.
* Received ebay valves that may be useful for an oxyfuel torch
* Change of plan: do plasma cutting off site, relax deadline pressure on torch table construction. Urgent task to update CEB drawings for Dec 18 build [[Hopper_Work_Statement]] - individual part drawings completed.
* [[TorchTableToolChainTesting#Alibre_-.3E_DXF_toolchain|Alibre toolchain]]
* Created github repository for hopper work [https://github.com/chuck-h/ose-cebpress-hopper here], unfortunately Marcin and Kavitha seem to have difficulty using it.
* Worked on concept for interchangeable touch-probe & marking device for torch table.

== 25-Nov-2012 thru 31-Nov-2012 ==
* got update from FEF regarding Dec 18 CEB build: no oxyfuel, using PP60 plasma on torch table, new tool chain with ImplicitCAD
* download ImplicitCAD to my laptop, limited functionality on Windows, see [http://christopherolah.wordpress.com/2012/02/06/implicitcad-0-0-1-release/#comment-923 here]
* first [[TorchTableTraining|training session]] with Rusty's Torchmate CNC Plasma cutter.
* visited Steve Hussey at Burning Specialties, a company that does CNC and pattern-follower oxypropane cutting with a huge older cantilever machine. Nice guy.

== 18-Nov-2012 thru 24-Nov-2012 ==
* sync grbl to [https://github.com/grbl/grbl/commit/5dd6d90122dce991a99eab5aa3a5c991dd5c938a upstream]..success.
* replaced mechanical microswitches on X1-X2 axis with photointerrupters..success. [[Stepper_Testing#opto|Testing]]
* contact Kavitha to coordinate torch table prep for Dec. 18 CEB build.
* research CNC oxyfuel torch cutting [[CNC_Torch_Table#Cutting_Torch]]
* research onsite oxygen generation (PSA)
* order some gas valves off eBay

== 11-Nov-2012 thru 17-Nov-2012 ==
* start log.
* ship Millermatic 200 welder (Seattle craigslist) by LTL truck to FEF. 400 lbs for $500; was that reasonable?
* [[OSE_Open_Source_Stepper_Motor_Controller|steppernug]] (open source stepper driver) schematic review with Darren
* received [http://www.mouser.com/ProductDetail/Sharp-Microelectronics/GP1A75EJ000F/?qs=%2fha2pyFaduhmXejJv184BikaBEqZykWweNnmsglkeuWVbMieAKIiNg%3d%3d photointerrupters] for torch table testing
* looking into "does not quite reach position" bug in my grbl branch

== Ancient history ==

First contact with OSE Sept 2011 briefly on site. I was in the area visiting relatives David Ihnen and Margaret Havens.

[[Category:Personal Logs]]

Lab Scale Fermentor

2013-09-02T07:11:02Z

ChuckH: /* Thermal Characterization */

File:Slowcooker thermal plot full.png

2013-09-02T07:09:56Z

ChuckH:

Lab Scale Fermentor

2013-09-02T07:04:51Z

ChuckH: /* Thermal Characterization */

= Lab Scale Fermentor =

This is a version of the [[Fermentor#System_Engineering_Breakdown_Diagram|OSE Fermentor]] primarily for process-development experiments.

It may be used on the [[Polylactic acid]] project.

== Prototype Development ==

I have acquired some components and will report here on construction progress of a low-cost "lab scale" (~1 liter) microbe fermentor. [[User:ChuckH|ChuckH]] ([[User talk:ChuckH|talk]]) 04:48, 29 August 2013 (CEST)

=== Chamber ===

Our basic chamber is a small consumer slow cooker ("crock pot"). This unit ([http://www.proctorsilex.com/products/slow-cookers-15-quart-slow-cooker-model-33116y.php Proctor Silex 33116Y]) has a glass lid with a soft rubber lip seal and costs about $15.

[[File:slowcooker_1.jpg|border|250px]] [[File:slowcooker_lidgasket.jpg|border|200px]]
----
The lid is made of glass. It appears ''not'' to be tempered, as the handle is attached by a screw through a drilled hole. This is good, because it means we can drill our own holes for stirring, sensors, and fluid lines. I will try using some cheap diamond core drills (the set shown cost $5 on Amazon).

[[File:slowcooker_lid_holes.jpg|border|300px]]
----
The heating jacket is a light-gauge aluminum bowl with a band heater around it. The heater has two elements, measuring 477 ohms and 200 ohms. The front-panel switch selects element 1, element 2, or both in parallel, providing 28W, 66W, and 94W respectively at 115V input. There is no thermostat.

[[File:slowcooker_internal2.jpg|border|300px]] [[File:slowcooker_internal_1.jpg|border|300px]]

It should be possible to control temperature with an arduino, thermistor, and solid-state relay, without any modification to the internals.

=== Thermal Characterization ===

In order to establish expectations and initial control parameters for the temperature control algorithm, we measured the heating performance of the chamber filled with water. The behavior is somewhat nonlinear, and has two significant thermal masses with different thermal time constants. Nonetheless, a reasonable single-time-constant linear model approximation can be obtained. Ambient temperature was ~30C. Initial fluid temperature was ~25C.

The thermal time constant is estimated at 120 minutes, and the temperature rise rate at the "HIGH" setting corresponds to an ultimate temperature of ~80C above ambient.

[[File:slowcooker_thermal_plot.png|border|300px]]

Spreadsheet: [[File:ThermalCharacterization.ods]]

{| class="wikitable"
|+Thermocouple locations
|-
| TC1 || Heating jacket, near heating element
|-
| TC2 || Heating jacket, center bottom
|-
| TC3 || Bowl, outside, near middle height
|-
| TC4 || Bowl, inside, aligned with TC3
|-
| TC5 || Water, ~4mm off bottom, centered
|-
| TC6 || Water, ~6mm immersed, off-center
|}

The lid steams up at higher temperatures, might interfere with observations.

<html>
<script type="text/javascript" src="http://s3.www.universalsubtitles.org/embed.js">
(
{"video_url": "http://www.youtube.com/watch/?v=cNEioVxZ6zs"}
)
</script>
</html>