I was printing out the x-end-motor for a new Reprap I’m designing yesterday. The bottom was printing beautifully:
I baby sat it for the first 2:15, and went to bed during the remaining 15 minutes of the print. I woke up the next morning to find this:
At first, I thought my hot end had jammed again, so I cleaned it out. After wasting the whole morning getting partway through a bunch of prints and wasting a ton of filament, I found the real culprit. The grub screw that holds the small gear onto my extruder motor shaft had completely unscrewed itself! The prints would start out OK, and then fail after the motor warmed up, and the heat softened the plastic of the gear, loosening its grip. Grr! Rather than reprinting the part, I’m going to just fill the gaps with JB Weld.