[Greenworks]

Calling on experience for a solution. First year garage machinist, so go easy on me. Running ST20Y with three jaw, three inch monster jaws. 0.625 6061 aluminum. Stickout is 3.5 inches. Kennametal topnotch 35° profiling insert running at 1800sfm, .001ipr, .06doc and I'm getting wild amounts of chatter. I don't have a steady rest or live center on this machine. Where would you guys start? Less/more DOC, less/more sfm, less/more feed? Maybe multiple bar pulls to reduce stickout? That's new programming territory for me, so I'm not exactly sure how to program it properly?

[rcs60]

at almost a 6 x 1 length to dia ratio you are going to have a hard time avoiding chatter untill you reach about 1.875-2.00 inches
chatter can also be caused by a harmonic balance between the machine, tooling, and material-- change 1 of the three and the harmonic point changes
i would also think that the insert would want to have a feed rate of .001-.005 (fine chip breaker) and would best perform at about .0025-.003 ipr
not sure if you are using a hi positive rake for aluminum but would try this as these inserts tend to reduce cutting force
i would start with about 2000 rpm and a feed rate of .003 if max machine rpm is 4000 then you don't lose by 1/2 the rpm and 2x ipr
I would also do the cut in a single pass to avoid the problem of reducing the dia. of the material and cutting further away from the chuck on multiple passes
I always work on the 3 x dia. ratio for a stable set up i consider a 4xdia. with program changes (speed, depth of cut, rpm)

[Greenworks]

I played around with it a bit with the -10 spindle button. Dropped the rpm to the floor with better results. 0.001 feed and 50 sfm. Takes 21 minutes to make the dang part now, but I've optimized the feeds and speeds on all the other parts I sell to this customer, so I'm kind of cutting it down the middle losing my a$$ on this part and winning on the others. Not tight tolerances either, so I'm able to throw them in the blast cabinet, and they come out looking Aok.

[Greenworks]

Oh, and I'm going to run 0.75 or 1.0 stock next time. Damn the extra 50 cents a foot, and damn the waste. Not nearly the waste of my time to run this slow.

[andre_77]

Slide the workpiece at the minimum possible distance.
Deal with the clamping elements as shown in the video.
Separate processing into several zones for Z axis.

https://www.youtube.com/watch?v=ojQxcmTt_vQ

[andre_77]

https://www.youtube.com/watch?v=8mzdJnvkYLU

[Greenworks]

Great info Andre! Thank you