[Zorbit]

Originally posted in Swiss Lathe forum by mistake. Sorry.

I'm using a Maier to make parts from Ti6Al4V Grade 5 Titanium, but the swarf is causing me problems. One operation is a long 1:50 taper and the swarf wraps around the job, meaning I have to pause the job and manually remove the swarf before head 2 can take the job for the stock end operations.

The finish I'm getting is really excellent, the tool inserts are those recommended for the job and they last well.

I have tried various speeds and feeds, as well as positioning the coolant jets from all angles - no difference. I'm using normal suds, water based mix.

A long google hunt produced a paper about using high pressure coolant accurately aimed into the cut, to force the swarf into a tighter curl and promote breakage.

My machine doesn't have high pressure coolant, but I'm thinking about trying to rig up something. Have any of you guys tried this ? OR, is there another method of removing the swarf I have missed ?

Thanks,

Zorbit.

[peteeng]

Hi Zorbit - have you heard of a chip breaker? Its a chunk of metal that lives behind the cutting tool that the string hits and its breaks the string? Peter

[Zorbit]

Hi Peter,

Yes, I've used chipbreakers, most of the inserts I use have them built in, and I have added extras. I even made a tool that fits in the next tool position that deflects the swarf away from the job, with some, but not 100% success. The titanium swarf is too tough to break, it simply bends into even tighter curls.

The most effective and current solution is to delegate swarf clearing duty to my assistant :-)

[Superman]

Hi Peter,

Yes, I've used chipbreakers, most of the inserts I use have them built in, and I have added extras. I even made a tool that fits in the next tool position that deflects the swarf away from the job, with some, but not 100% success. The titanium swarf is too tough to break, it simply bends into even tighter curls.

The most effective and current solution is to delegate swarf clearing duty to my assistant :-)

There is so many variables to consider...
depth of cut... are you deep enough to allow the swarf to hit the chip breaker?
RPM.... fast enough to drive the chip into the chip break channel
Feedrate... high, to give a thicker chip so that any bending creates fracture which will create smaller chips
Coolant supply... to stop work hardening of part, to chill swarf to allow fracture, to keep tool edge sharp

dont allow tool to stop while on surface of material as this will wear out the cutting edge & work harden material

It is good that you are doing a taper as this will vary the depth of cut and stop "notching" on the roughing tool cutting edge

[Zorbit]

Hi Superman,

Thanks for replying. I run this job on a sliding head "Swiss" type lathe, so I only get one pass to cut the taper from nearly bar size at 8mm to the small end, the depth of cut varies a lot over the length of the taper but often the swarf doesn't break at all. If I run without flood coolant the swarf is orange in an instant.

I do get some notching on the tool, at a point where the bar diameter is when depth of cut is deepest. A strange effect that doesn't happen with any other metal I use, but it's slow and not a big deal.

Cheers,

Z