Hi,

This is my first post, so forgive me if I commit a faux pas. For background, I am trying to mill holes in a 0.125'' thick sheet of 6061 Aluminum that spans 17'' by 14.75''. These holes range from 0.15'' to 0.2'', so the holes are relatively small. However, each time I try milling with my 1/8'' Carbide bits, they end up breaking shortly after. Could someone review my settings and try to identify the cause, because I've gone through about 8 bits and numerous forums to no avail albeit some improvement.

Bit Size: 0.125"
RPM: 24,000 or 400 hz. (Maximum for milling machine)
Feed Rate: 30 ipm
Plunge Rate: 15 ipm
Type: Carbide
Maximum KW: 0.8 KW

These settings came from cloudcnc's speeds and feeds calculator, so I'm not sure how exactly to fix it.

The cuts come out pretty clean, but they simply snap after some time. I've observed that when it snaps some aluminum seems fused to the bit. Any ideas? Thanks!