I have printed a couple weeks perfectly fine with my Ender 3. Two weeks ago I changed the firmware but the settings were all fine and resulted in good prints.
Now, suddenly during a print the extruder motor started to under-extrude.
I thought "hey, could be the file" and used a test file that printed well two weeks ago: Under-extrusion, barely a line.
I looked at the extruder, no filament grinding, no clicking from lost steps or moving against pressure. The Bowden tube is firmly seated though.
I measured what is coming out: instead of 50 mm I ordered to push into the hotend got 28.7 mm. So I went and looked at the steps/mm, which is 93, exactly what it is also on the TronXY X1, which uses pretty much the same extruder setup but for a different style, same sized gear.
I cleaned out the nozzle nevertheless, but that didn't change the results.
What might be wrong and how can I fix it?!
- Touching the filament while I was printing a freshly sliced test, I realized it DID lose steps, just the filament did slip back (almost) quietly. Pressing a finger on the filament made me able to feel the shiver in it.
- Inspecting what was printed showed, that the nozzle had migrated against the print platform a little over the weeks.