Y axis has gone bad all of a sudden

[bkmartin]

When I print a test cube now, my y-axis seems to have problems. Any ideas on what could cause this? My belts are tight and I tried increasing the stepper voltage and I get the same result. The x-axis appears ok

View from side (of printer of a test cube). The irregular edge on the right would be at the front of the printer. Rear is similar


View from front of printer [edges are uniform]



Last week, the same filament and same gcode printed fine.

[printbus]

Is the pulley tightly secured on the Y-motor shaft?

With the stepper motors disabled, does the Y-bed seem to move on the Y-rails consistently from front to back? Or are there any spots where the bed seems to catch or stick?

[bkmartin]

The pulley is very tightly secured and the bed moves smoothly. I was also concerned about the security of the glass as well, but it seems to be very secure as well. I can't find what is wrong.

[printbus]

This is a long shot, but I'd also check the alignment of the Y-belt. If the belt is rubbing against the wood bracket at the front, perhaps the belt is catching on it and causing problems.

[bkmartin]

I discovered the issue after printing a solid cube and saw that both the X and Y walls were perfectly flat. In other words, the problem was only occurring when I printed a cube with a single nozzle width wall. The problem was caused by the cooling fan. When I disabled the cooling fan for this single wall thickness cube, then the problem went away. Should I be surprised that the cooling fan was blowing the wall that much out of alignment. Should I reduce my cooling fan speed for normal operation?

[printbus]

Interesting. I wouldn't think a cooling fan could mess up the corners like that.