TIL switching to climb milling on aluminum stopped my chatter issues

I was running a batch of 6061 parts last week and got tired of the constant chatter on the finish pass, so I switched the toolpath to climb mill just to see what would happen. The surface finish came out way smoother and my end mill stopped making that awful screeching noise. Has anyone else had this fix work better than messing with feed rates?

3 comments

3 Comments

matthewkim23d ago

Climb milling saved my bacon on some thin wall 6061 parts too.

ross.kevin23d ago

Keep an eye on your radial engagement with climb milling, it can chatter worse on thin walls if you take too wide a cut.

claire_walker23d ago

Three thou depth of cut with a 3/8 end mill in 6061 was my magic number. I read somewhere that climb milling puts the cutting forces into the machine casting instead of the spindle bearings, and it made a difference on my old Bridgeport. @matthewkim is right about thin walls, but what got me was how much quieter the machine got when I switched. That high pitched squeal you hear with conventional milling is the tool rubbing before it cuts, and with aluminum it just worsens the built up edge problem. Watch your chip thinning though, climb milling can double the actual chip load if you aren't careful with your speed. I run about 20% lower RPM than standard feeds and speeds tables suggest for climb cuts.