I've this MPL160 palletizing robot that had a L axis replaced. After this was done the robot moves in a non linear way.. Let me explain; if you record a P variable point using a User Frame reference, then you for instance modifiy the Z coordinate lets say 300mm above, and you press FWD to carry the robot that new position, the robot moves but if you measure the distance travelled you will find its about 295 (minus 5mm). If you now insert 700mm in Z, without recording the previous 300mm point, and FWD the robot to that point, then mesaure again you'll find its about 690 (minus 10mm), and so on. It's like there is a proportional factor of 0,95 that applies to the movement. I hasn't made a X or Y measurement but I guess it could behave similarly.
Could an error in the TCP calibration make such error?
Thanks in advance...