How to Fix a Nozzle Jam

If you ever notice that the printer is "air-printing," you may have a jammed print head. To unjam your printer, follow this procedure:

  1. Go to the Octoprint CI Edition software interface.
  2. Heat the nozzle to the printing temperature of your material (200°C for PLA).
  3. Wait for nozzle to heat.
  4. Set the retract distance to 50mm and click Retract 3 times.
  5. Once filament is retracted, remove 3" from the end of the filament. Cut the end of the filament at a 45 degree angle and straighten the first 3" by hand. If possible, use a brush to clean the teeth of the extruder hobb.
  6. Click the Extrude button 2-3 times and re-insert filament into extruder when prompted.
  7. Wait ~30 seconds after engagement for filament to purge through the hot end. Filament is engaged when it is difficult to pull upwards from the print head with more than a gentle tug and can be seen advancing into the extruder.
  8. Once you see plastic emerge from the nozzle, your nozzle is unjammed.

Nozzle jams are often due to several common factors. Attempt to remedy these issues before re-printing to avoid jamming again:

  • Print temperature too high: the filament may soften too high up in the print head and lead to a jam. It is often best to print at the lowest end of the recommended temperature range and increase as needed.
  • Obstruction: if the molten plastic emerging from the nozzle does not come out of the nozzle straight downwards, but is kinked to the side, then it is likely the nozzle is partially obstructed. A nozzle swap is recommended.
  • Print temperature too low / print speed is too fast: The viscosity of plastic decreases with rising temperature. If the viscosity of the plastic flowing through the nozzle is too high compared to the print speed, then your printer may jam. If this is the case then it is best to decrease your print speed.