Tried a 0.031 end mill on aluminum and learned the hard way about chip load

I was running a job last Tuesday on a little Tormach 440 and needed to cut a slot 0.035 wide in a 6061 part. Figured I'd just grab a 0.031 two flute carbide end mill and send it at 12000 RPM with a 10 IPM feed like I do with bigger tools. First pass sounded fine but on the second pass the tool snapped clean off about halfway through the slot. Turns out I wasn't clearing chips and the flutes packed up solid. I slowed the RPM down to 8000 and dropped the feed to 6 IPM with a peck cycle every 0.005 and it finished the rest of the part no problem. Has anyone else had success with tiny end mills on aluminum using a different strategy? I'm thinking about trying a single flute next time to get better chip evacuation.

2 comments

2 Comments

bell.jessica13d ago

Did your buddy try wax to hold down the chips?

the_mary13d ago

Respectfully, I gotta disagree with that idea. Wax can get messy and actually make things harder if you're trying to reposition anything later. I've had better luck just using a strong adhesive or even double-sided tape for stuff like that.