Chips Wrapping up in Titanium

[ChristianK]

We are currently having problems with a part and the chips that wrap up on the last operation before part pickup. I am trying to change feed rates, use high pressure and so on. The only option i have left is to suck the part out of the guide bushing, let the chips fall off and then shove it back in but that would be an amazing beating on the part as well as the machine.

Any ideas?

It is a star ecas20 machine.

[PixMan]

I've had similar issues with that material and some others like 316SS, also in thread whirling (bone screws.)

I did OK with stopping the spindle and reversing direction at a low speed, then bring a tool down to just over the thread diameter (perhaps .005" away, or even less), then back it out of the guidebushing with HP coolant on. This effectively "unscrews" the stringy chips.

HTH

[ChristianK]

Pretty much doing that right now just sucks because it wears the back of the guide bushing out and has a hard time bringing the part back into the machine.

[PixMan]

Pretty much doing that right now just sucks because it wears the back of the guide bushing out and has a hard time bringing the part back into the machine.

Wearing out the guide bushing? Sounds like you're either running too fast on the "unscrewing" (should be 200rpm or so), or using a steel guide bushing instead of carbide.

Both problems are fixable. I've never had any problem running the part back into the GB from behind unless there was a burr left on the O.D. I never have that problem because I always chamfer downward from the stock O.D. towards the center.