[oseaman]

Newbie here. Does anybody here have experience cutting foam insulation on CNC router? Looking for tooling, and speeds/feeds advice.
I do a lot of large 2" deep pockets, and 3" deep perimeter cuts.

Currently using a 1/2 dia. 8 flute 3" loc endmill meant for honeycomb from LMT Onsrud, running the spindle at 18,000rpm, and feedrate is 600. I've had the endmill for a week, and there's already signs of wear on the zrn coating on the endmill. Is that normal? Finish is great, although not important for what I'm doing. Runs pretty quiet. Makes super fine, small chips.

Any advice/thoughts deeply appreciated. Thanks!

[oseaman]

The bit got retired after about a month of use. Scorched, and dull. I'm going to cut my feed rate, and plunge rate in half, and see how it helps the new endmill I got. I was plunge milling at 100in/min and it began to melt the foam as the bit dulled. Is 8 flutes too many for this application? The smaller chips get picked up easier by the dust collection it seems. The bit is not usually above room temp after a cycle. Still looking for guidance.

[oseaman]

The bit I'm using is $200. I'm not trying to blow through one every month. I am cutting a very large amount of foam 5 days a week. Is this wear to be expected?

[dharmic]

I hope you get some answers, oseaman - I have some projects coming up this year that need a bit of CNC love applied to blue board.

[oseaman]

dharmic I'm finding out the old fashioned way right now, and i'll gladly share what I've learned. Godspeed!

I'm starting to think this kind of tool wear is just to be expected when I'm running it 40 hours a week.

[skrubol]

I wonder if this subforum just isn't very active. Might get more responses in the woodworking router area.
I would think for something as soft as XPS foam, the fewer flutes the better. I'd look into two-flute, as well as single or 'O' flute cutters.
If you're seeing melting occasionally, your RPM's might be on the high side and your feed might be on the low side.
I'd run the feed as fast as you can until either surface finish degrades or it looks like there are problems getting the 'chips' cleared. I've also found that conventional cutting can leave a much nicer cut.