I searched for this in the forums, but couldn't find it. Acrylic buildup on bit

I broke yet another bit trying to cut acrylic. It was going fine but the acrylic kept building up on the bit. Then the bit broke :confused: Is this just going to happen or is there a way to safely get the acrylic buildup off of it while in operation? The bit I used was a 1/16 fish tail 2 flute.

The build-up could be caused my melted acrylic, faster feed rates and shallower cuts will not allow so much heat to build up and melt the acrylic.

That being said, I have not cut much acrylic…just a few pieces.

There’s no doubt in my mind that friction is the culprit. I messed up a good sheet of mirrored acrylic trying this :frowning:
I went with the default depth per pass and should have made it more shallow. I wonder if the bit I chose played into enabling the buildup. The design had fine detail so I tried to go with a small-ish bit. Ugh, I can’t afford to keep breaking all these bits (and acrylic) while I learn things the hard way :stuck_out_tongue: Thanks Erik.

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Bring the spindle speed down, increase the feed rate and do shallow cuts with a bit that can produce big chips.

The build up is purely heat melting the material onto the bit.

You may switch to down cut bits. That’s what I did for any Plastics. Lot better results.

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You might also try cast acrylic. I’ve been cutting it without a problem - it is much more tolerant of the heat and melting issues than extruded acrylic.

Thanks for that link. I just bought that, and a 1/16" one as well.

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