So, I could not help myself, I had to try.
I used that 4"x5"x 6mm sheet of cast acrylic:
I picked a 90deg Vbit, and figured I would target a 0.002" chipload (which on a V-bit is a notion that does not really apply), so at 10.000RPM I used a feedrate of 0.002 x 2 flutes x 10.000 = 40ipm
For plunge I picked 75% of the feedrate, so 30ipm (I liked to plunge fast in plastics)
The cut was ok but you see those long strips there instead of small individual chips?
This tells me I should have pushed the feedrate and plungerate even further, I was borderline-melting.
Here’s a video of the cut
And here’s the result after I peeled off the protection :
Not perfect, but clean enough.
EDIT: and by that I mean, had I not used my battered 90Vbit that has seen a lot of abuse since I got it three years ago, it would have been cleaner.
On your stock Z-axis you may not want to plunge too fast, but hopefully that will give you a starting point. If I had to do it again I would probably use 10.000RPM, 60ipm feed, 40ipm plunge.
On a stock Z…I don’t know, maybe 60ipm feed and 20ipm plunge.