Is CNC right for my project?

Hello all. I have a project in mind and I’m not sure whether CNC will be right for it. I need some styrofoam carved out into the shape of a car. Probably about 2 feet long. I’m thinking since CNC works top down with a bit, it won’t be able to carve anything more narrow than the widest point, below that point (I hope thank made sense). Basically the underside of the panels, shapes of the wheels, etc. If I’m wrong or someone has a better solution, please let me know.

Thanks in advance!

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CNC could be a good option, but yes you’re limited in your depth of cut (usually no longer than the length of the bit sticking out of the spindle, as you want to avoid crashing the spindle on anything) and of course no undercuts or small nooks and crannies. Plus 3D carving can take many hours, depending on work size, bit diameter, stepover, etc.

Alternatively you could get sheets of styrofoam and CNC/laser cut 2D slices and stack them on top of each other. You could sand/carve the resulting object to add smoothness. This could also theoretically allow for undercuts for the wheel wells and windows, etc Could add some holes so that you can stack all the slices on a dowel or something for proper registration. Just an idea.


There is software that can slice the shape, think like a loaf of bread. You can cut out the slices 2D and stack them in the proper order, and sand/carve to the final shape.

Peace, Wolf

You’re thinking about this the right way when it comes to 3-axis CNC. 5 axis could do the whole thing, but we don’t have one of those, and even if we did, programming that is a whole other artform. CNC can certainly help you achieve this, but it will be multiple operations any way you slice it (pun intended).

If it’s Styrofoam then a hot wire machine will be the fastest. and will also give you very good resolution.


Hey thanks for the suggestions! I hadn’t thought about slicing and stacking the object. That hot wire machine is pretty awesome. I’m gonna give it some thought. What is the name of the software that’s used to slice up the 3d model?