I wanted a custom cover for an electronic gismo I am working on, and happened to have a few remaining acrylic sheets from Carbide3D (the one I used had a paper-ish protection on each side, which helps a lot to get a clean cut):
2-flute 1/8" square endmill
Feed rate 700mm/min
plunge rate 150mm/min
Turned out exactly like I wanted, with almost no clean-up required.