Just realized I was using the wrong feed rate for aluminum for like 5 years

Used to run my feeds at 0.002 per tooth like steel, kept getting terrible surface finish. After I switched to 0.008 per tooth last month, the chips actually break right and parts come out smooth - how do you figure out your feeds for softer materials?

3 comments

3 Comments

emmaclark1mo ago

Run a chip load chart for aluminum, it's way more aggressive than steel lol.

betty_wells1mo ago

Chip load charts are great until you realize aluminum wants to eat your tool like a hungry dog while steel just politely nibbles. I learned that one the hard way with a new end mill and a 1/4" plate that turned into a musical instrument. Maybe I should just stick to wood, at least that stuff doesn't fight back.

robin6281mo ago

emmaclark nailed it about aluminum wanting way more aggressive feeds, but here's what gets me - did you bump your speeds too or just change the feed? I ask cause when I switched from 0.002 to 0.006 on my 3 flute end mill I forgot to drop the rpm and the thing started welding chips to the flutes like crazy before I realized what was happening. Even now I still catch myself second guessing because running 18000 rpm with that high of a feed just feels wrong in my gut even though the numbers say it's fine lol.