Hi all, I am having trouble cutting 1/8" ABS with a small end mill (1/16" TiN coated carbide square end mill). I normally cut ABS we a feed rate of about 1300 mm but because this 1/16" end mill is so tiny I lowered the feed to 1000 mm in hopes of not snapping it. To my surprise the ABS started clumping on the end mill even before it was done cutting the first hole. I tried lowering the RPM on a Dewalt 611 from 2 to 1 (18k to 16.5k) in hopes of lowering the temperature on the end mill but it didnt change anything.

I then started thinking maybe I had some wonky ABS and threw on a 1/8" end mill (from the shapeoko shop) and ran the same program to see if it had the same problem but this end mill cut through the material like butter with no issues.

The next difference is that the 1/16" end mill is a 3 flute vs the 18" end mill which is a 2 flute. Maybe it needs to go even slower to try to cool better and get chips out of the way. Any direction on what I should try next?

To summarize:

1/16" 3 flute square end mill, Feed 1000mm, RPM 16.5k, 1mm depth per pass, melts ABS

1/8" 2 flute square end mill, Feed 1000mm, RPM 16.5k, 1mm depth per pass, does not melt ABS