Fadal VMC 3016 I Need Help PLEASE!

[HBZ USA]

I have a vmc 3016, it is a 1992 but was remanufactured in 2002.
I am having issues with my Y axis. The circular interpolation is off.
Basically what is happening when I go to cut a circle I have a flat spot on the top?
I have replaced my couplers, checked the backlash, and adjusted my amplifier signal gains.
I am trying to adjust my gibs, but I am stumped bryond this?
Any help would be greatly appreciated.
Thanks
Jay

[Neal]

Jay--
Start with verifying the level of the machine. Next adjust the gibbs and straaps in all three axis. Next verify the thrust bearing slop and ball nut to ball screw slop. Verify that your servo loop gain is adjusted for 595 because you have DC servos.
If you still have the problem start checking the tachometer in the motors, the resolvers, the possibility of a weak motor or a weak amp.
Since you have replaced the couplers, verify that the two sides of the couples are not bottomming out as they rotate.
This is a lot of checking but this should help you find the issue.
Neal

[ishaham]

Jay

You might have a backlash problem, since you check your backlash in static mode you can not see the real value, the next step is check the machine with a ball bar, this will monitor the dynamic backlash.