Hello all,

I have a VMC20 that gives an alarm and shuts down while doing helical interpolation (cutting threads). This problem is intermittent, but it happens often enough to be a PITA. When it goes into alarm, I send it home, cold start and resume operations for a while. At times it will be run fine for several hours. This all started a couple years ago, but seems to be getting worse with time. I replaced all 3 resolvers this past summer and thought that the problem was fixed, for a while, then it started doing it again. Regular circle interpolation has not been a problem. Replacing the resolvers improved the accuracy on cutting round holes and surface finish. I have also replaced the X & Y ball screws & bearings.

I am at a loss at where to look next.

Thank you in advance!
Gary LaValley