13. Molding and casting

Due Wednesday May 20 2020


individual assignment:
1. design a mold around the stock and tooling that you’ll be using,
2. mill it (rough cut + (at least) three-axis finish cut),
3. and use it to cast parts

group assignment:
1. review the safety data sheets for each of your molding and casting materials,
2. then make and compare test casts with each of them

My plan to complete the assignment

  1. CAD: Design a vacuum forming pattern in Onshape
  2. CAM: Generate tool paths (gcode) with FreeCAD
  3. Mill foam to create vacuum pattern
  4. Vacuum form parts


I found this video to help get me started with creating tool paths in FreeCAD:
FreeCAD- The Powerful Path Workbench for CNC Maching and Gcode|JOKO ENGINEERING|


I decided to vacuum form this half-dome topper to add to the face shield I have been manufacturing for the Illinois PPE Network. This half-dome topper will allow protection from splashes that may go over the top of the shield. I already had the fame parametrically designed in Onshape, so it didn’t take long to design half-dome topper I wanted to vacuum form.

Next I used the Boolean function of Onshape to subtract the half-dome topper from a tool block. Next I used various extrudes to cut away the cavity side of the tool block leaving the core tool block. The core tool block is the part I need to make the vacuum form pattern.


Then I used the FreeCAD Path Workbench to Generate toolpaths to use on our x-carve milling machine. I followed the steps in the video above in the Research section: FreeCAD- The Powerful Path Workbench for CNC Maching and Gcode|JOKO ENGINEERING|
I will use the gcode from FreeCAD and it’s GRBL post processor to generate g-code to run our fab labs x-carve milling machine.

Mill Foam

I will post the results of milling the vacuum form pattern here.

Vacuum Form

I will post the results of vacuum forming here.

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