Aidan Williamson Log

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Old Logs:

July 17, 2019

Don't have edit access on Soil Mixer Design Doc so I'll record my thoughts here:

  1. What propels the stabilized soil mixture out of the hammermill?
  2. Relying on gravity and ratio of areas to dose quantities of soil and earth. This, in my opinion, will be irregular. You would have to be able to change the size of the stabilizer aperture in the field.
    1. Based on pH for lime. Do a sample every so often
    2. Based on color for cement?
  3. The raw soil would need to be crushed and dried before it will fall into the drawer in a repeatable way. This kind of defeats the purpose of a hammermill.
    1. I could see this propagating the error we have in block size throughout the system. Relying on the soil to fall into a hole the same way each time. Might double the error, right? Double the random uncertainty in block size. Or give a systematic shifts in error during a shift or certain working condition.
  4. An auger system could meter the input of soil and stabilizer in a more controlled way while still using only one actuator (motor instead of cylinder - though maybe it works out to an extra motor). A variable pulley could be used to set the stabilizer ratio. This is an off-shelf item.
    1. Example of variable speed pulley system. If we use the same auger size for soil and stabilizer, then gear reduce the stabillizer auger to give 3% to 10% the speed of the soil auger. If you need more than 10% stabilizer then you are using a very low clay content soil and using a ton of cement - rethink the soil blend and if you need to, buy a different pulley.
    2. Does variable pulley work at low speeds?
      1. Planetary Geardown? 6 axis CNC Torch Table to produce most components of planetary geardown?

July 16, 2019

Tried to go to the dev meeting to discuss soil mixer per discussion with Marcin last week but nobody was there save an AFK Abe.

Need feedback on workshop tools and infrastructure list at Belize CEB. I'm not including any hardware or materials for the house - just the tools that are required to build it. Just working from what I can imagine would be necessary. Another more experienced set of eyes would be good to glance over what I have listed so far.

Thinking about soil prep: for Marcin's hammermill concept, how do we get dirt at OMC (optimum moisture content) before it goes into the hammermill? One way could be to figure out OMC by volume of dry dirt, volume of water and have laborers fill 5 gallon buckets with dry, screened dirt and add water from another bucket with demarcated OMC line. This unmixed bucket of water and dirt goes in to hammermill. Assume that the dirt has (non-uniformly) absorbed the water AND that the hammermill will actually give a homogeneous mix. I don't see why the hammermill would give a homogenous mix unless you cap the mixing chamber to prevent material escaping before a homogeneous mix is obtained. This would take longer than a press cycle so it would have to mix more than 1 block's worth per round.

July 11, 2019

Mader's Machine

July 5, 2019

CADded D3D Mill assembly in 2 days

June 20, 2019

June 16, 2019

File:Taper to Straight adapter.fcstd File:Taper to Straight Adapter Wheel Hub.fcstd

Feb 25, 2019

I made a new tube builder when I heard mine wasn't working in FreeCad 0.16 on Ubuntu.
The new file is based on the Sketcher, Draft, and Part workbenches whereas the original file was based on the Sketcher and Part Design workbenches.

File:Alternative Universal Tube Builder.fcstd

Here is a video explaining the new file approach

Feb 23, 2019

Video showing making of a spreadsheet parametrized cad file.

Feb 22, 2019

Made a video about the tube generator and improved the file by adding HoleSpacing parameter to spreadsheet.

Nov 20, 2018

Here is a version uploaded to the OSE Wiki. It should work but may have design flaws. I'm using an O-ring to seal the cylinder in the cap trepan groove. This is questionable.
File:Universal Cylinder Builder ADW.FCStd


I've been working on a cad file for the Open Source Cylinder. Here is a link to the alpha stage of the file. DROPBOX The end-caps are square with a trepan machined for the tube to seat. The caps could potentially be parted so that a welding operation replaces a machining operation for the tube seat. The Rod is welded to the Piston in my version.

Like the universal tube builder, I'm trying to make it parameterized from a spreadsheet. Here is what the parameters look like right now:

Name	Input (Inches)	Output (mm)	Note
Cap Side Length	4	50.8	
Cap Thickness	1	25.4	
Tube OD	3	38.1	
Tube Wall Thickness	0.25	6.35	
Piston Thickness	1	25.4	
Piston Seal Inner, Height	0.3125	7.9375	
Piston Seal Inner, ID	2.125	26.9875	
Piston Seal Inner, OD	2.5	31.75	
Piston Seal Outer, Height	0.25	6.35	
Piston Seal Outer, ID	2.125	26.9875	
Piston Seal Outer, OD	2.5	31.75	
Stroke	12	304.8	
Rod OD	1.5	19.05	
Rod Stickout	2.5	63.5	
Cap Seal Outer, Height	0.25	6.35	
Cap Seal Outer, OD	2	25.4	
Cap Seal Outer, ID	1.495	18.9865	
Cap Seal Inner, Height	0.25	6.35	
Cap Seal Inner, OD	2	25.4	
Cap Seal Inner, ID	1.495	18.9865	

Need to add a few parameters like tie-rod diameter. I think the model may need to be scrapped. Especially if one looks at the dependency graph lol. I didn't take as intentional an approach to modeling it as I could have.

I believe it is a worthwhile effort, though. A user could generate the CAD for a cylinder of different sizes by simply entering data into a spreadsheet.



Left

Notes

The caps as I have drawn can be easily made on a lathe and mill. How i would make this: Cut the plate to size and machine square. Surface grind for extra credit. Put the four tie rod holes in but make them half inch reams. Using shoulder bolts, attach the plate to a lathe jig or 2 bolts and 2 dowel pins. To make the lathe jig, press fit a piece of 4" or similar crs into a thick plate with the bolt pattern on it and weld. Face the jig on the lathe after welding. The bolt pattern should be put in after the welding operation. Use custom vise jaws and maybe a small bore for picking up the center. For the rod end cap, drill and bore the rod hole then bore internal grooves. Then cut trepan groove. For the base, it's just a trepan. Make those in half a day including making the jig.

As an alternative, I was imagining "slicing" the caps into layers, like 3d printing, and then welding the slices together.

For plastic cylinders, I would start with pvc or abs pipe as the tube. I'd go down that road before I started messing with a metal prototype.

I'll keep thinking about it.


Aidan

Nov 5, 2018

Here is a file that might be helpful for y'all. Open the Universal Tube Builder file and use the spreadsheet to create tubing with all dimensions parametrized. Holes will automatically be set to 4" spacing. I can change that if you want. You can define the standoff for the first hole.

File:Universal Tube Builder ADW.FCstd

FreeCAD expressions for constraint solver