Heat or axis problem?
I recently face issues when printing which I'm not able to solve. They look like either heat or axis problems.
The picture shows the same part printed using Prusament PETG in Jet Black:
- The left most is a print from a few months back were everything was working fine.
- The middle is a recent print where I just the 'Generic PETG' settings in PrusaSlicer instead of the Prusament PETG which results in a 10 drop in nozzle temperature.
- The right most is a recent print using the exact same gcode as in the left print (Prusament PETG settings)
I already tried reassembling the whole extruder, exchanging Nozzle, Heating Element, and Temperature sensor, run all calibrations (XYZ, first layer, PID) multiple times and even downgraded the firmware to 3.8 (as the first print was done using that firmware).
I'm kinda clueless what could be still causing this and would welcome any kind of suggestions.
Best Answer by Neophyl:
Looks like a loose pulley to me. Small offsets like that are usually down to the belt being loose (which is usually noticeable) or the pulley. If you dont tighten the grub screws in the correct order then over time they loosen which allows the pulley to move slightly on the stepper motor shaft. The more they loosen the more movement you get until finally they can spin freely.
The fact that it gets worse over time in your example prints just makes me think that even more. I dont know what the orientation of the parts was so you will need to check both of them, but it looks like only one is loose.
You must tighten one of the grub screws against the flat first. It must also be perfectly square with that flat spot. Once that is tightened you can then tighten the second grub screw. This is often referred to as a 'set' or 'jam' screw as that is what it is designed to do. When loosening the pulleys for maintenance you want to reverse that so always loosen the set screw first before attempting the one against the flat.
RE: Heat or axis problem?
Looks like a loose pulley to me. Small offsets like that are usually down to the belt being loose (which is usually noticeable) or the pulley. If you dont tighten the grub screws in the correct order then over time they loosen which allows the pulley to move slightly on the stepper motor shaft. The more they loosen the more movement you get until finally they can spin freely.
The fact that it gets worse over time in your example prints just makes me think that even more. I dont know what the orientation of the parts was so you will need to check both of them, but it looks like only one is loose.
You must tighten one of the grub screws against the flat first. It must also be perfectly square with that flat spot. Once that is tightened you can then tighten the second grub screw. This is often referred to as a 'set' or 'jam' screw as that is what it is designed to do. When loosening the pulleys for maintenance you want to reverse that so always loosen the set screw first before attempting the one against the flat.
RE: Heat or axis problem?
Thanks a lot for your valueable input.
Your intuition was correct. I already checked the belt tension, but didn't think about the pulleys. Of course, the pulley in y-direction was a little bit loose.
Now everything looks awesome again! Big thanks!