Layer skipping (potholes on the model)



Good afternoon, everyone. I’m facing an issue with my Snapmaker F250 involving layer skipping. I’m not an experienced 3D printer user, and I recently acquired my printer. Mostly, I’ve been printing small parts, and the problem wasn’t as noticeable, but when I attempted to print a vase, the defect became very pronounced. Initially, the print goes well, but as it approaches completion, the defects become more frequent.

@BattleDog Interesting. Looks like the nozzle stops extruding and recovers over and over again. My guess would be either heat creep/too much retraction or too low printing temp/too fast printing speed…

Perhaps you could provide some additional details?

  • Material
  • Print temp
  • Bed temp
  • Print speed
  • Retraction distance

Material: PETG, printing temperature: 240 ℃, bed temperature: 75 ℃, printing speed: 60 mm/s (standard speed profile in Luban), retraction: 1mm.

@BattleDog I don’t have much experience with PETG. I just use it for supports. Usually with temps around 260-ish. Perhaps you could start by increasing the print temp and see if that solves it. If there’s too much stringing you could increase the retraction length aswell. I believe 1 mm is quite low for PETG.

@Rwide In regards to retraction, it’s actually the opposite. 1mm is the MAX for just about any filament on the Snapmaker, including all versions of PLA, PETG, and ABS/ASA.

@BattleDog
Immediate solutions:
Dry the filament
Slow down your print speed…45mm/s at most
Reduce retraction further…0.5mm @ 20mm/s
Check slicer’s “Combing Mode” set to “Within Infill.”

Ultimate solution:
Tune EVERYTHING, and it will fix/prevent 99% of all issue…all tuning steps listed here at the end of the first post:

If you use the single extruder module it’s underextrusion, try to calibrate your e-steps.