We have a 1996 4020 with factory pallet changer. We have a simple job of drilling holes down a part the length of the X axis travel. The actual measured distance started out .017 less than the distance programed at 37 inches. We took machined parts to our Romer Arm for inspection. We tried several things to verify the problem. We had vises at each end of the table that we could measure with our 40 " Versa-Gage. Edge find the outside and measure it. Machine travels are short to Versa-Gage measurement. Took the part and put it in the other similar Fadal and using a pin jogged from hole to hole. Machine travels match the measured part. So far we have swapped drive cards, new resolver and swapped Y and X axis motors. We have no backlash as the screw was replaced in the last couple of years. Checked machine level. Gibs and straps are properly adjusted. The values in the ball screw calibration are zero. We now see .010 on a test part. And yes, it appears progressive down the travels. We have talked to our Fadal service techs that have been in here for years and they have no ideas.
Simply stated: It appears the actual machine travel over the length of the X travels are less than the value programmed or stated on the machine display.
Any other ideas?