Dear Experts
We have a SPM (Special Purpose Milling Machine) with 4 servo controlled axis
Operator loads component in fixture on X axis and starts cycle
There is neither APC nor direct feedback, rather only Motor feedback via pulse coder
X axis motor is coupled to axis thro belt and pulley arrangement
Only when machine is put off and on, X axis reference position shifts by upto 3mm but never shifts during machining etc
As it is shifting only when put off and on, we are suspecting malfunctioning of encoder and or feedback cable
We have checked Ballscrew for play, backlash etc - found Ok
Request for suggestions
Regards