Milling Plastazote LD33 closed cell Foam - Any milling advice?

[Zeeflyboy]

As mentioned I got the best results with single flute down cut, make sure they are nice and sharp. I used Belin but there are plenty of single flute down cut bits around... Choice is probably most limited by cutter length depending on what you want to do, although there is no problem doing 2 passes with the second pass below cutter height (as long as shank is same diameter as cutter obviously), it’s just slower. I think the Belin only go up to 38mm on a 6mm cutter.

I bought those here https://www.cncroutershop.com/uk_en/...wn-spiral.html

The most important thing I found is to use conventional milling and NOT climb.

Depth of cut is fairly unimportant. The foam is soft enough that it won’t test the rigidity of any half decent machine, same goes for width of cut and it more becomes a question of having swarf that can clear easily. I had good results using 16k rpm and 3,000mm/min on the 6mm tool, and I think around 20,000 on the 3mm.... but there’s certainly plenty of room to play around there.

For hold down I would box it in if working very close to the edge, and a vacuum plate would be the easiest way to keep it stuck down.