D shaped turning

[Greg_J]

Hello,

Is there a way to turn a D shaped work piece?

 

There are limitations on the machine making the part and the max one could rotate the work piece.

 

If so what tool path would you use?

 

I have some ideas but I wanted to see what other people would use.

 

 

Thanks,

Greg

[CJep]

You could do that with a multiaxis tpath if you have C Y capability

[crazy^millman]

Turning it would need a special control and machine IMHO. Like CJep said Mill/Turn would be the way to go.

 

HTH

[Greg_J]

In a regular lathe, in theory you could write code to move the X and C axis, the C would have to move very slow and the X would have to move very quickly. I wouldn't be efficient but it could be done?

 

I believe I saw a video on Youtube I can't seem to find it.

[GoetzInd]

With only X and C you wouldnt be able to maintain cutting edge clearance unless you had some crazy relief and at that point it would probably be to fragile to cut. Also, you will need some pretty good processing to be able to get any real metal removal. Usual C axis lathes are pretty light on the processing and look ahead department.

 

Mike

[Newbeeee™]

Previous place we did a load of work on implants which weren't regular 'spiral' for the thread but which were actual threads with radial and axial relief, so it cut into the bone easier...

The machine that was chosen by the brains behind it (and he was) was a dmg twin spindle because it had a siemens control and the ball screws were of such a pitch that the screws could respond (in and out) at a fast enough speed with the spindle running. Siemens being the fastest control as well (at the time).

It was real interesting until the company I was at went bankrupt just as we placed the deposit on the machine...

So to turn D, you are limited to chuck rotation and slide in and out response (speed), which apart from turning pistons (small oval) is impractical.

 

I've seen a machine with a driven head that is mounted on the X slide, and it rotated with a cutter in the same axis as the main chuck, but the X is synched to the C of the main spindle. So as the main spindle rotates at speed, and the driven head rotates at speed, the X axis moves the driven head 'in and out' to match the C position, this giving you a D.

Is this what you're thinking, because I looked on youtube and couldn't see it either

[Joe788]

With only X and C you wouldnt be able to maintain cutting edge clearance unless you had some crazy relief and at that point it would probably be to fragile to cut. Also, you will need some pretty good processing to be able to get any real metal removal. Usual C axis lathes are pretty light on the processing and look ahead department.

 

Mike

 

^ This. Gotta have Y axis as well:

 

[Greg Williams]

You do not need a Y axis

 

at 3.15 there is offset turning, Create a XZC program in mill and run that

[civiceg]

I believe that is the youtube video you are referring too

[AlbertZini]

http://www.youtube.com/watch?v=L5LgYd9j3MQ

[cherokeechief79]

perhaps you are referring to polygon turning which is completely different.

[Newbeeee™]

^^^yuuuup. I think I was.

[Joe788]

You do not need a Y axis

 

 

It just depends on how far off center your feature is going to be.

[GoetzInd]

It just depends on how far off center your feature is going to be.

 

Yes. If you are turning a slightly off center dia. you could get away without Y although cutting conditions will not be optimal. If you are cutting a "D", you are really going to need Y.

 

Mike

[Greg_J]

Many of those videos are exactly what I was referring to.

 

Greg Williams video was the one I remember.

 

Thanks for the responses.

[Greg Williams]

Just bear in mind that the part does not come out very round, well at least mine did not

[Greg_J]

I'm just going to play, I've been running a mill for a long time now and I just got a lathe. I was wondering what it could do.