Thanks for the replies,
We talked to Fadal directly, and they steered us in the same direction. We first checked the gibs with a tenth reading indicator in the spindle against the jaws of a vise, then the proper way the manuals say to. There was a tremendous difference between the two so that led us to think it is a mechanical problem. We then did the pry test with the indicator at the end of the ball screw and found a full thousandth slack in the thrust bearings on both X and Y, so we are in the process of replacing them. We will probably do Z also if we have the time. This machine is 10 years old.
Also a tip for you Fadal owners out there: we had a 4020 we replaced all the thrust bearings in a couple of years ago and we did not see a whole lot of difference in one axis. Tore that axis down again and found the aluminum block the bearing presses into was about a thousandth deeper than the width of the bearing. I guess after twelve years of use or so the aluminum block got a little hammered out. I just faced off the cap to capture the bearing rigid and it then checked decent. We have had no more problems on that machine.
By the way, do a pry test with an indicator on the thrust bearing block of a 4020 and you will wonder how it will ever make a decent part to begin with. It will make you think about replacing the aluminum blocks with thicker steel ones.
Thanks for all the ideas, I will try to keep you up to date.
Alloyspec  |