Torch Table Build
Proposal
See proposal at http://openfarmtech.org/Lawrence_Proposal.pdf .
You can also see the working agreement,Lawrence Kincheloe Contract
The purpose of this project is to enrich both the participant and the Factor e Farm project. The scope of this specific project is to build the seeds for a MegaRap, which is a modification of the origional Torch Table designed to expand the range of build materials and capabilities. This is in the spirit of the RepRap project, but at a larger scale and lower precision. The initial goal is to design and build a torch table that can be added on to in the future but is still functional in its own right.
Bill of Materials
Bill of Materials 5172T12$2.50 per Pack
| Item | Number | Cost | Further Info | Purpose | Aquired? |
|---|---|---|---|---|---|
| Computer | 1 | $300 or less | http://www.linuxcnc.org/ | To run Linux cnc | yes, IBM Laptop |
| Xylotex 4 Axis Drive Box with 425 oz.in. Motors and Cables | 1 | $460.00 | Xylotex Stepper and controller | To provide motion control and movement precision | Yes |
| V-Groove Bearings 3/8 inch | 12+(spares) | $9.95 each, $119.4 + (S&H + spares) | VXB V-Groove bearings | To provide low friction linear motion | no |
| Hot rolled steel 2"x1/8" plate | 4 feet | 4ft 1 $10.00 $10.00 | Metalsdepot | To provide material for motor mounts | no |
| Hot rolled steel 1"x1" square tubes 16 gauge | 35 feet | Metalsdepot | To provide structural support | no | |
| 200011 (1/2” sq. x 72” 20 DP 20 Deg) | 4-5 | $24.80 each, $99.2 to $124 | Standard Steel Specialty | rack for gear to ride on | yes |
| Track for linear motion | 3 x 1/8 inch cold rolled Plate | 35 feet | Metalsdepot | To provide material to make rails | no |
| Bolts 3/8 inch, 1 1/2inch long | 12+(spares) | $7.46 per Pack of 50 McMaster | McMaster | For attaching V-Groove Bearings | no |
| 3/8 inch threaded rod 6 inches long | 8 + (spares) | McMaster | for connecting the top and bottom carage | no | |
| 3/8 inch nuts lots | Part Number: 90473A031 | For locking threaded rod in place | no | ||
| 3/8 inch washers | lots | Part Number: 90126A031 | For locking nuts and for spacers | no | |
| 1/4 inch washers lots | McMaster | for holding against stepper motors | no | ||
| 1/4 inch nuts | lots | McMaster | for spacers and such | no | |
| Bolts 1/4 inch dia. , 1 3/4 inch long | less than 100 | McMaster | gear rack | no | |
| 3/8" Bore | 4 | $15.37 Each Total $46.11 | McMaster 5172T12, 1327K113, Part Number: 5912K12, 6412K11 | Attaches to stepper motors and interfaces with gear rack | no |
| thrust bearing 3/16" | 16 | $1.96 Each, $31.36 Total / $1.05 Each, $16.80 Total | McMaster | no | |
| Thrust Bearing | McMaster Nylon Part Number: 2797T1 | allows the motor to swing freely | no | ||
| sleeve bearing | 4 | $1.34 each, $5.36 total | McMaster Part Number: 6391K143 | to connect between the stepper motor and the gear, will also add a bit of adjustable length | no |
| support flange sleeve bearing | 4 | $0.59 Each, $2.36 Total | McMaster Part Number: 2938T14 | supports gear | no |
| 10 gauge bolts | lots | $7.78 per Pack of 50 | McMaster Part Number: 92610A245 | stepper | no |
| 10 gauge nuts | lots | $1.54 per Pack of 100 | McMaster Part Number: 90480A011 | stepper | no |
| Washers | 100 | $2.50 per Pack | McMaster Part Number: 95601A330 | Holding bearings | no |
| Grease | 1 | cheap | McMaster | For greasing rails | no |
| z axis tension spring | 1 | $7.93 per Pack of 1 | McMaster Part Number: 9640K244 | returns z axis head to safe position | no |
| stepper saftey spring | 4 | $10.00 per Pack of 6 | McMaster Part Number: 3114T79 | no | |
| cutting lubricant | Kerosene | 1/2 gallon | $10 | Wikipedia Cutting Fluid Tapping holes and such, might not be needed | no |
| Skateboard Bearing:Sealed:ABEC-7 | 8 | $9.95 | VXB | no | |
| Total 1 Approx. $1582 | Torch Table Wiki | one torch table, sans stepper motors, tools, and torch |
Working Concepts
X axis
Design Rationale
- Rack for x motion - cheapest, most robust solution for precise motion
- Spring-loaded x and y motors
Y axis
Design Rationale
Z axis
Design Rationale
Blender Concept
File:Factor e Torch Alpha 3.blend
Plasma Torch
Torch vs. Plasma Cutter
- Comes down to initial cost versus long-term cost
- Plasma cutters - consumables cost $20 for 5 new electrodes and nozzle heads
- Electrodes are rated for 45 minutes to 60 minutes for 1/2" steel
- More expensive versions state they last 4 times longer - are heavier and have better temperature control
- For anything above 1 inch, torch is better
- Can be interfaced with a computer cheaper than Torch
Desired Characteristics
We are looking for a machine rated for 1" milled steel that will cost roughly between $700-$1100. We are limited on budget because we are funded primarily through donations at the moment.
Since we want to use the machine for cnc work, we are interested in the pilot arc starting, or touch off starting. We could also use high frequency starting, but we would have to shield our motor controller and any other equipment in the area. Would it be possible to shield the plasma cutter? We want to be able to cut thin material with the torch so it is likely we will want the pilot arc starting feature.
Do you have any suggestions on a best practice method of attaching a plasma torch head on a cnc machine?
We would also be interested in a plasma cutting head that would be easier to mount. Currently in your accessories page you only list a model that is appropriate for plasma cutting by hand. Also, since this machine needs to be flexible we would also like the option of using the plasma cutting head by hand. Through looking at competitors websites, its clear that its easy to offer one or the other and switch them at the DC power inverter, but how easy would it be to add a 45 degree flexible head that can be fixed for either cnc overhang cutting or hand cutting? This seems like an easy adaption, but I might be missing something.
Also, we are interested in the engraving feature. Especially the controlled plasma pulse feature. The reason is that we are interested in precision surface removal, and gouging because we have an idea to use this machine as a plasma lathe, combined with a cnc controlled head. This isn't a requirement, but we are very interested in getting the maximum amount of utility from this tool.
Plasma Cutters Considered
- cheap
- 5 year warranty
- made in china
- cheap
- 1 year warranty
- made in america
Plasma Cutter PC Interface
A simple relay circuit, the components depend on the plasma cutter interface.
Team
- Deep in the continental US underground...
