PROBLEMS CIRCLING FANUC 18 CONTROL

[PICMAN]

HELLO,
I'M HAVING A PROBLEM WHEN CIRCULAR MILLING? EVERY TIME I COMPLETE A FULL CIRCLE, IN 4 QUADRANTS, THERE IS A DIVOT LEFT FROM MY MILL. IS THIS A PITCH ERROR COMP PROBLEM?
THANKS,
PICMAN

[Dan Fritz]

It's more likely to be backlash compensation or something wrong with your spindle/toolholder lockup that may cause tool deflection.

Are you taking a significant cut that might apply large forces to the tool? If you're taking a very light cut, then look at your parameters for backlash compensation. Many people try to set backlash comp with an indicator using the wrong method for measuring backlash. The result is backlash comp that is larger than what's needed. Of course, you could also have a ballscrew/ballnut or a thrust bearing that's got some play in it, which would require a mechanical repair. Backlash comp does not eliminate the mechanical backlash. It just masks the real problem.

[PICMAN]

I'M NOT SEEING ANY BACKLASH COMP IN MY PARAMETER LIST? IS THIS SET INA KEEP RELAY? ALL I SEE IS PITCH ERROR COMP.
THANKS