Cutting 3mm cast acrylic

Good evening. This is my 1st post on here and I’m hoping for some help with cutting 3mm cast acrylic. I am using a 1/16 o-flute. 70ipm@18000rpm. Depth of cut is .038. Im getting pieces melting on to my endmil as it’s performing a contour cut and its scratching my surface. What am I doing wrong? Thank you for any help/advise you all have to offer.

Melting is too much heat. Usual advise is lower RPMs / higher feedrate.


I run at 100 Plus IPM at lowest speed. “O” flute


See the video(s) on acrylic at:


One thing that helps a ton with the surface finish on the sides of the cut, especially in plastic, is using a strategy that does an extra pass at least half the endmill diameter, outside the periphery. When I’m cutting plastic I do:

A pass that is roughly at least half the endmill diameter away from the material.
A pass that leaves 0.005"-0.010".
A finishing pass to the final dimension.
A second finishing pass to get it as clean as possible.

Here are 3 views to help visualize…since I need visuals. :slight_smile: