The nozzle moves but leaves nothing, the extruder clicks, or the print stops partway. It's a clog, full or partial, and it's almost never fixed from the slicer.
It happens on any FDM printer. Setting names are Bambu Studio's: in Orca Slicer almost all have the same name, and PrusaSlicer or Cura usually have an equivalent.
Where do I start?
Two questions to sort out what to check. It's a guide, not a sure fix: every printer and every filament is different.
Check in this order
- The printerIf it printed fine yesterday and not today, it's almost never the profile. Check the plate, the nozzle and the room: printing at 15 °C is not the same as at 30 °C.
- The filamentA spool that has soaked up moisture gives strings, bubbles and brittle parts. Dry it before changing settings, and pick that filament's profile in the program.Filament pages
- The quick checksThe “First” list below: it's the fastest to check.Go to “First”
- The slicerOnly now, the settings below, in order. Change one thing, print a small test and compare. If you change three at once and it gets fixed, you won't know which one did it.Go to the settings
Check in this order
- The quick checksThe “First” list below: it's the fastest to check.Go to “First”
- The filamentA spool that has soaked up moisture gives strings, bubbles and brittle parts. Dry it before changing settings, and pick that filament's profile in the program.Filament pages
- The testsCalibrate your filament with these tests:5Retraction
- The slicerOnly now, the settings below, in order. Change one thing, print a small test and compare. If you change three at once and it gets fixed, you won't know which one did it.Go to the settings
Check in this order
- The quick checksThe “First” list below: it's the fastest to check.Go to “First”
- The previewStep through the slicer preview layer by layer: that's where you spot missing supports and odd areas in this part.
- The slicerOnly now, the settings below, in order. Change one thing, print a small test and compare. If you change three at once and it gets fixed, you won't know which one did it.Go to the settings
First
- Heat the nozzle to the filament's temperature and push by hand: if it's hard or the strand comes out crooked, it's clogged. Clean it with the needle or do a cold pull (pulling the warm filament out so it drags the dirt along). Your printer has its own unclogging guide.
- Check the filament path: a spool that doesn't turn, filament tangled or brittle from moisture, a kinked PTFE tube, dirty extruder gears.
- If you switched from a hot filament (PETG, ABS) to a cooler one (PLA) without purging, the leftovers won't melt at the new temperature: preheat to the previous filament's temperature and purge.
- A loose nozzle or a blocked hotend fan makes the filament soften too early and jam.
- Very long retraction also clogs: Bambu recommends no more than 2 mm (Printer › Extruder › Retraction).
Then, in the slicer (in this order)
- Nozzle temperatureFilament › FilamentOutside the filament's range, Bambu Studio warns the nozzle may clog: respect it. With fiber-filled filaments or special nozzles, raise it 5 to 10 °C.
Fixed by calibrating:5Retraction
Tried everything and it's still the same? Calibrate your filament with the 8 tests, or write to us with a photo.