Need Help!- Fanuc OM-Ic

[tturnbull50]

Has anyone ever experienced the loss of machine zero reference points? Always seems to be Z zero and about 52>53 mm short of correct point, but no ALARMS caused major crash. This is driving me nuts as manufacturer says nothing can be done!!! 6 times now.

[timlkallam]

Maybe the cupling between the motor and the ball screw is lose ,mark it and see if its sliping.

[fanuc-support.c]

Coupling loose - Switch moved - Switch broke.

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[tturnbull50]

Checked them all, seems ok???? This fault is intermittent, runs fine for several weeks then just losses m/c "Z" zero.

[Andre' B]

When does it move? While machining or when homing after powerup.

I wonder if the Z pulse on the encoder is happening too close to the same time the home switch is happening so that some times it goes to the next Z index pulse.

[WGoyer]

I think Andre is onto something. I'm curious, however, with such a new control, why you are needing to re-zero. If you have just encoders on the motors, I wouldn't think that the zeroing switch is ever getting used since everyone uses absolute encoders now.

If you have linear scales, then you might be zeroing every day. Then, the marker pulse could, in fact, cause the axis to stop too close to the switch breaking point. Every so often, the switch could break in a slightly different place and cause a one grid (reference counter) jump.

So, do you have scales?

Warren
www.uptimecorp.com

[stevo1]

I would first check to make sure everything is tight as Fanuc has stated. Encoder, switches, etc.

If your reference marker is too close to the cam switch then it is possible that it will home in different positions. Although when this happens it will typically reference an exact amount different when it does 1 to the next. IOW when reference is normal it will be 0 and when it skips to the next pulse rev it will usually be exactly the same every time it changes. You may be 0 one time and 53mm off the next but never 54mm 52mm 53.5mm et. If you are to close you can do a gridshift.

Stevo

[Sung daecheol]

Hi, tturnbull50!
Move Home switch or dog(plate) to right or left 5~10mm.
Good luck!

[todor viorel]

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