My old foreman told me to never run a 3/4 inch end mill over 2500 rpm in aluminum

Honestly, I thought he was just being overly cautious. So on a job about six months ago, I pushed a similar tool to 3200 rpm thinking I'd get a better finish faster. Ngl, it worked for maybe five parts before I heard a nasty screech and saw the flutes were completely welded up with aluminum. The whole spindle had to come down for cleaning. He was totally right about the heat buildup. What's the fastest you guys will run a 3/4 carbide end mill in 6061 without coolant?

2 comments

2 Comments

ivanbrown3d ago

Ever think that old rule was just talk?

tarahart3d ago

My buddy tried pushing a 3/4 inch tool to 3000 rpm in dry aluminum once. He ended up with a solid aluminum slug where the flutes used to be. That old rule about heat is definitely there for a reason.