Throwing wrapped chips from endmill

[Ewood42]

I saw an operator doing something kinda brilliantly lazy the other day I'd never seen before, and I'm weighing whether it would be worthwhile to incorporate into our post as a MI triggered routine for holes we know are going to be trouble. We machine nothing but plastic here. As any of you who've worked with it know chip management can be a pain even with the right cutter sometimes. On some programs, if the cutter is getting dull and the chips are wrapping up, between helical bored holes he hits feed hold, spindle reverse, flips coolant on and off, and start spindle back in the other direction. He does all this in like 2 seconds with the manual overrides, so I know with code we could go just as fast if not faster. Works nearly every time to throw chips off the cutter.

My main concern would be about how hard that is going to be on the spindle. Any thoughts on whether this is worth implementing?

[YoDoug®]

I say any tricks you can do to help with chip management are good. We have tool cleaning cycles integrated into our B-axis millturn posts that clean the tool at the end of every toolpath. It adds a few seconds of time, but it allows us to run lights out with minimal ATC problems from chip wrap. 

Years ago I worked at a shop that machined a lot of cast steel parts with stepped bore in the 3"-5" diameter range. On finish boring it was hard to get the chips to break and it would leave a nest in the bore for the next tool to catch. I ended up getting one of those metal dog leash corkscrews that you screw into the ground and mounting it in an ER holder. Feed into the hole clockwise to snag the chip ball, then retract, then reverse to fling the chip ball off. Wine corkscrews also work well for small holes. 

[Leon82]

When you're tapping a spindle spooling up and down reversing quite often. I don't think you're going to hurt it

[Matthew Hajicek - Singularity]

I've occasionally added a spindle reverse to thrown chips off a drill.  I've also seen, but not done, having a wire brush mounted somewhere in the machine to run the tool backwards against while pulling up.