chatter problem

[bdrmachine]

Thanks guys for all the input! I have not found a supplier for the left hand helix cutter that was mentioned. Does anyone have a good source for these cutters? Would an indexed cutter be worth trying since they usually do not have any helix? What type of finish can I expect with indexable cutters?

Thanks
Brian

[One of Many]

When any cutter does its grab/release cycle it is trying to take more material than it can physically support on its own accord. One trick we would do is to dull the cutter a tad by running a cratex stick down the flutes a few times. You may also notice this more on new cutters verses reground cutters due to the rake angle in the flute becoming less positive on the regrinds, so less tendancy to grab. Cutter pressure will increase and so will deflection, but we are after a happy medium and will take what we can get.

Lots of times we just let it chatter on the roughing climb cuts, then take the most effective finish pass using a conventional path so the EM is always loaded without a chance to unload and swing in air desiring to ring in harmony with other mystery contributing factors.

Sometimes it just ain't worth fighting. At least until it gets so annoyingly consistant that the experts are called in before the men with white coats come to take you away!

DC

[One of Many]

After a bit more thinking of the chatter problem. I have some questions as to your actual procedure in milling this pocket.

You mention a cutting depth of .1 but not the length of cut of the 3 flute EM. 2.5" for a 2.2" pocket would be the best choice to limit chatter. Excessive length won't help.

The amount of stepover is another big factor. If the EM is stepped over greater than 1/2 of its diameter, it will be trying to climb and conventional cut at the same time. Long cutters will put up more of a fuss used in this manner. The more teeth in the cut, the worse it will get too.

Just thinking out loud. I'd imagine you are already past this problem by now.

DC