Tried a 1/4 inch end mill on aluminum and got bad chatter

I was cutting some 6061 aluminum on my Haas Mini Mill last week and thought a 1/4 inch two flute end mill at 10k RPM would be fine. But I got bad chatter and a rough finish on the part. Turns out I should have used a higher helix angle or dropped the RPM to around 6000. Anyone else run into this with aluminum on a smaller machine?

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2 Comments

grayc272mo ago

Drop that RPM way more than 6k. 10k is screaming for a 1/4 inch end mill in aluminum, especially on a Mini Mill. I run 1/4 inch two fluters around 5k or even 4.5k with a .025-.035 chipload and they cut butter smooth. Your chipload was way too low at 10k, that's what caused the chatter. Try bumping your feed up to match the lower RPM too, that helps a ton with finish.

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murphy.linda2mo ago

Wow, that low of RPM in aluminum won't cook the coating off?

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