Originally Posted by
daedalus0x1a4
To clarify: Varimill Endmills are only manufactured with four or more flutes from solid carbide. This particular endmill has four flutes.
Lowering the load per tooth seemed to add to the problem which generally tends to be the case when making deep cuts with large diameter end mills.
Reducing the step over to .050" helped marginally but not enough to keep the vibration out of the cut.
Going to try to increase the feed to .010" per flute tomorrow. Will lower step over to .030" if that doesn't work.
daedalus, I think your problem is tool deflection leading to chatter.
If you cut at 0.050", and your total stickout is 3", 600 sfm, 0.006" chipload, G-Wizard predicts 0.0016" deflection, which is too much. You want 0.001" or less roughing, and less still for a decent surface finish. If you've got more than 3" of stickout, the situation is even worse.
This assumes you're using your pre-drilled hole to cut the full 2.813" along the flutes.
You can back off several ways.
- Less stepover. You have to go all the way down to 0.0085" stepover to keep that deflection down.
- Helix in rather than circular interpolate. If you use no more than 1" of flutes in the cut you can increase that stepover to 0.063".
Looked at another way, you can only put about 5 HP to work with 3" stickout before you get too much deflection for roughing.
Best,
BW
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