EZ-Trak series II is always 0.100 off home after shutdown

[sdey]

We have an EZ-Trak series II that has a home issue. The machine will run with no problems or errors untill it is shutdown. After power up, home is always off 0.100 in the X axis. It is always off in the same direction. The operator will rehome the machine and it will run fine. Any suggestions

[machintek]

Move the home "dog" or actuator for the X axis such that the switch makes about .025 inches sooner.
The marker pulse and home switch are too close together, thus the variation.

George

[NC Cams]

We had a similar problem on Y.

We also found that it would lose concentricity when checked via plug gaging a hole and comparing it to computer screen.

Solution: motor encoders needed cleaning/servicing and tach feedback from motor was acting up.

If the motors are SEM, Clarkson near Chicago is the factory service center in USA and their prices are reasonable.

[NC Cams]

UPDATE: After having our motors checked, we still had problems with homing and the milling of round inside and outside circles.

Were fortunate enough to learn of BPT Machine in Carol Steam Ill. Brian came by and did a thorough tune-up of the machine. Great guy and very helpful.

Not only was/were the home switches off but we also had some system BIOS and servo tuning issues. He also replaced the OEM hard drive with a DOM (flash disk) - we still had the 10 year old oem hard drive.

Machine now homes and runs deadly true after a tune-up. It cuts round holes and repeats coming home to preciseness we never saw before. Any OEM qualified service tech should be able to do a similar tune-up.

NOTE: our machine was in pristine condition and had been treated to some special tune-ups of the ball screws and ball screw bearings. A tune up of the electronics will not compensate for tired screws and bearings.