how to shape polyethylene foam with CNC machine
Hello everyone, I want to start manufacturing the body parts of my design. I am using polyurethane foam to shape it with the CNC and obtain the desired profile, now my problem is that I do not know how I can establish the part in the software and then be able to modify the foam with the CNC, if someone can help me with the technique or send me a link that shows how to carry out the entire process, I thank you very much. and may almighty God bless you
1 Answer
Milling foam parts is fairly easy, once you learn the basics... Depending on the type of CNC you have, body parts are usualy 1 surface / 1 operation relief cutting, like sign making on a Shapeko... You layout the part on a flat surface in you CAD software, drop the edges to remove undercuts, set the Z axis to zero on the flat surface, and you're ready to go. More complex shapes will require multiple setups are piecing seperate parts together for your final molding.
You can run foam much like wood... Due to the density, the CNC can run at higher feed speeds, just watch your spindle speed. You also want to make sure your bits are as sharp as possible, as dull edges can rip & tear instead of making a clean cut.
the wrong speeds can easily melt & burn foam, It'll take experimenting & practice to get a feel for it... and different density foam behaves differently, so each will present it's own learning curve.
For body work, you'll want a dense, small grain foam for the smoothest surface... I use pink & blue insulation foam for practice, one-offs & non-critical layups... you'll want to source a provider for larger 1 piece tooling foam blocks. Stay away from floatation foam as it's very porous.