[derwood]

Having a consistent position error on the Fanuc servo turret, either direction.
This causes the curvic coupler to misalign and never seat far enough to clear the limit switch.
When we got the machine a few years ago the turret was slightly misaligned but seated ok as it seemed to rotate slightly as it seated.
Now it is out about .400" and can't seat.
It's very consistent and happened in the middle of a run.
Now the turret shutters slightly as is approaches home, kind of like it has a lot of friction in the mech assy.

It seems the encoder has slipped (again?) or something mechanical has come unkeyed.

I tried changing the grid shift parameter which sends the zero return detect signal into another full rotation of the encoder. I'm looking for a temporary fix until we have time to tear everything apart and check the mechanicals. this is one massive turret. Ugh! Does anyone know if the turret home position can be adjusted in the control after it receives the detect signal and slows before homing?

Thanks for any help you may be able to offer on this.

[theemudracer]

my turret rotates slightly before locking into postion also. It is caused by the turret not being balanced. (Too many heavy tools close together). Mine never hangs up in auto mode but it will become stuck inbetween positions if I rotate the turret in manual mode sometimes.

[PMT]

The MTB should have a procedure to re zero the turret motor. the newer lathes I see all have Absolute position coders so you need to follow their procedure. As far as balance The MTB may be able to help you out there as well. When the turret clamps, the servo releases. If the servo releases before turret fully clamped an out of balance turret could shift clamping tooth to tooth. Most, not all, MTB will have a timer to keep motor in servo lock until fully clamped.