Hey guys,

I've got some nice Plastazote LD33 closed cell foam https://www.efoam.co.uk/zotefoam-plastazote.php


My intention is to make some nice tool drawer inserts for the CNC (e.g. here is the model so far for one drawer - haven't placed all tools yet:




So far my experimentation has led me to conclude that it likes very fast feed rates and relatively low RPM, but i still haven't got super clean results out of it yet.

I'm currently just playing with an 8mm 2 flute helical carbide end mill that's designed for aluminium as that's the only tool I have that's long enough. I have ordered some long foam specific straight 2 flute cutters - one 3x32mm and one 4x42mm, but those will take a little while to get here as they are coming from aliexpress.


So with the 8mm 2 flute, the best I have tried so far is 6000mm/min and 10,000rpm, and for whatever reason it much prefers conventional milling to climb milling... all of which gave me this on my little test block (ignore left corner, that's where the top layer of foam didn't heat weld very well to the bottom layer):






Has anyone played with this stuff before? Any advice as to feeds/speeds/cutter types?

I'm guessing that the smaller diameter end mills might be quite useful in bringing the effective speed down without having to drop rpm below what the chinese spindle is happy with.

Cheers for any input!