Check this problem out.....
My shop recently purchased this very used Mighty bridge type vmc. It has a Mitsubishi Meldas 520AMR control. I got it up and running and ran a few simple programs to check for axis position repeatability. To my amazement when it tried to do a basic square tool path, with cutter comp on, every time it rounded a corner with the G02 or G03 command it would be way off in X and Y on the next depth cut pass from .005 all the way up to .100!! Each time it went around the square the location would be random on the next pass, no pattern at all. Program does the same thing whether it's Radius or I and J called out. However if I remove cutter comp so the tool path does 90 degrees on the corners with no radii it's perfect. Is it backlash or parameters?
Any ideas?