Dear Sirs

Quite often we face problems related with size variation in 2 axis Grinding and Turning machines

Like we got a 2 axes Turing machine v replaced ballscrew, end support bearings, external encoder on the shaft of ballscrew, lubrictation is ok still suddely we find vertical axis has come down by 150 microns causing scrap. When we check repeatability of axis by using dial in Automatic program for 50 cycles, we find it to be ok and repeating but only during cutting, suddenly X comes down

We also checked alignment between self centering chuck center and tailstock

Kindly advice what else is missed out

Regards,