Sub spindle pickoff Tight Tol.

[Omega]

I have a turned part that has a cbore on ea end, the cbores have a + - .001 dim measured from the bottom of the face cbore to the bottom of the back cbore, I have made the parts for years doing two ops with no problem. The qty's are going up per month so I would like to do the parts complete.

Here's my question...Is it likely that I could machine the first side then pick the part with the sub and finish machine the back and expect to hold tol. between the ends ?

Machine is a Tsugami TM8A...it seems to be a very accurate and repeatable machine.

Microcentric collet chucks both ends.

 

[pcasanova]

if they are the dead length should be no problem.

 

[Dan from Oakland]

Can you put your Z stop on the sub against the bottom of the 1st cbore? Would probably make it easier to hold the tol.

 

[Scruffy887]

I have a part that is a bit like that, but I am strictly Mazitrol. In the transfer process there is a PRESS function where the sub applies pressure to fully seat the part into the stepped jaws. This is a fairly thin part and sub has just a tiny purchase of the transferred part.

 

[13engines]

My apologies if this doesn't apply to your Mazitrol control. On my Mori (Fanuc) lathe the "press" type function you speak of is a separate or different command. Meaning you can pass off parts with cutoff from synchronized main to sub, with or without including the press function. Maybe a deep dive into your books might turn up the same capability to run with or without press and its detection.

 

[Orange Vise]

This can be tricker than one might think because there are a lot of factors at play:

1. Z repeatability of the turret on the main side
2. Tool wear on the main side
3. Z repeatability of the subspindle when it comes to grab the part
4. Z repeatability of the turret on the sub side
5. Tool wear on the sub side

The cumulative error of all of the above needs to be +/- 0.001 in Z.

Furthermore, the turret is going through nearly its entire travel when it cuts on the main, then moves to the sub. This amplifies thermal growth errors.

It's not impossible but it'll be more difficult than what you're doing now, since running everything on the main with a hard stop eliminates 3, 4, and 5.

 

[Scruffy887]

My apologies if this doesn't apply to your Mazitrol control. On my Mori (Fanuc) lathe the "press" type function you speak of is a separate or different command. Meaning you can pass off parts with cutoff from synchronized main to sub, with or without including the press function. Maybe a deep dive into your books might turn up the same capability to run with or without press and its detection.

Oops! Mazak calls it PUSH.
Ideal way is to have a probe with a probe cycle for each part.
But I think it is worth trying, probe or not, and you may need to dial it in with a bit of VooDoo. I typically toss 3-4 parts setting up a new program. But I run my parts from 60" bars of Acetal and if a Cbore is too tight I toss the part and change the program and make another.

 

[Omega]

I have a part that is a bit like that, but I am strictly Mazitrol. In the transfer process there is a PRESS function where the sub applies pressure to fully seat the part into the stepped jaws. This is a fairly thin part and sub has just a tiny purchase of the transferred part.

I looked in my manual and there is an M code that controls A axis thrust torque, I'll give it a try.

Thanks for all the responses

 

[Scruffy887]

Almost forgot this part. Make sure you record jaw pressures on your setup sheet.