Milling EPP Foam

Does anybody have any experience or plans to mill epp foam on their x-carve? I’ve got a couple projects lined up once my machine gets in (and i get comfortable using it, hah) that involve 2.5D carving forms out of epp foam but I can’t really find much good information on the Googles about other people’s experiences other than folks milling on a huge commercial machine.

I was mainly hoping to find info about end mills, settings and images of how it turned out to try and find finishing techniques, as I imaging it would leave a pretty rough surface.

Any help is appreciated!

We have a bit of information on that on the Shapeoko wiki:

Forum user Cwalster noted in post Re: Foam cutting?, “EPS and EPP … the trick is to use HSS, flat end mills and to conventionally cut it. If you don’t you get a fuzzy surface.”

Original post:

Using a single-flute endmill so as to slow down the effective RPM of the tool will help as well (as discussed on )

I wonder what type of milling he’s referring to, 2D cutouts or 2.5D shapes?

After a little reading I decided to buy one of these bits to try, mainly because it says ‘foam cutter’ in the name.

When you start carving with your new bit and you find the foam is building up like cotton candy, that means your revolutions of the bit is too fast and the foam is melting to the bit. If this happened the foam will be very hard to remove from the bit. I remove the bit from the collet and dip the bit in lacquer thinner and the hardened foam will melt off, not scraping. I have a 48x96 PRT and when cutting foam, I turn down the speed of the bit to about 8000 RPMs and feed rate of 3IPS. You can also keep some of the static-cling of the chips from your CNC by wiping the surfaces with a dryer sheet.
Sorry, I am a rambler when it comes to this stuff.


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Great advice! How does the finished surface come out usually? Any tips on smoothing it out our does that not apply with your application of the foam?