I finally switched from a 4-flute to a 2-flute end mill for a big aluminum job

Had to make 500 parts from 6061 and was stuck between using my usual 4-flute or trying a 2-flute for better chip clearance. I went with the 2-flute, ran it at 18,000 RPM with a 120 IPM feed. The chips cleared way better and I didn't get any of the built-up heat I was worried about. Finished the whole run in about two days without a single tool change. Has anyone else found a sweet spot for 2-flute speeds in aluminum that's different from the book numbers?

2 comments

2 Comments

the_harper8d ago

I ran a 2-flute on our old Haas at 15k with a 0.08" stepover and it just sang. The book said 12k but it left a better finish when I pushed it. I mean, the chips were these perfect little curls that just flew out of the cut. I don't think I'll ever go back to a 4-flute for roughing aluminum again.

hugo1538d agoMost Upvoted

Man, that sounds beautiful. Meanwhile I tried pushing a feed rate once and just made the world's most expensive aluminum glitter. My finish looked like a cat scratched it. Still chasing that perfect chip flow you're talking about. Guess I need to stop being such a wimp with the rpm.