I think I found the Y axis problem. It looks like the X motor mount was catching on impefections of the rod it rides on. Two points seem to be a problem:
1. The block that constrains the lower side had a sharp inside edge. This seems to have been due to the molding process. Mine are molded parts, not printed or laser-cut. I removed both of these blocks (one on either side of the motor) and ground down the edges.
2. The rod was also catching on the side of the hole it passes through. When properly calibrated, the rod shouldn't even touch the plastic. I could've sworn I had that right in the first place. Best guess is that the X axis shortened over time due to a) X belt tension and b) the fact that I didn't tighten the X axis rods enough. I loosened the X belt, adjusted the X axis length and tightened everything back up again.
After that, I cleaned and lubricated the Y axis rods and used the stepper exerciser to run it through its paces. Seems to be behaving now.
Sunday, November 30, 2008
Posted by Steve DeGroof at 2:47 PM