Filament grinding, which is accompanied by a “clicking” sound coming from the extruder, usually happens when the extruder gears are unable to push the filament further towards the nozzle. Over time, the gears grind away the filament, until they can’t grab it anymore.
The clicking sound means that the stepper motor is having to suddenly exert more force than a specific preset threshold and it's jumping back by one or more steps (skipping) to relieve the pressure. It can be a mechanical issue, electrical issue, software issue, jammed hotend or a combination of any of those factors.
First, you need to remove the filament from the extruder. In order to do that, open the idler door located on the right side of the extruder by unscrewing the M3x40 screw(s) on the opposite (left) side (the one/s with the spring on them). Now you are able to manually remove the filament using the supplied pliers.
Update the firmware
Make sure you are running on the latest firmware. Double check that you are really downloading the correct firmware for your printer version.
Slice the model again using the latest version of PrusaSlicer and see if the model is not corrupted or incomplete. Try to increase the hotend temperature (Filament settings -> Filament -> Temperature °C) by 5 - 15 °C
Make sure that your extruder idler is properly tightened. If the extruder idler screws are overtightened, the gears will not push the filament properly. Try to loosen (or tighten) the extruder idler screw(s) (with the spring). Their tension must be accurate (neither too tight nor too loose)
Undo the wrap protecting the extruder cables and check whether the cables are not damaged. Also, please unplug all of the extruder cable connectors, check for any potential damage, crooked pins or similar.
Dirty extruder gears
- Make sure that your extruder gears are clear of any leftover plastic. You can clear the plastic with a sharp corner of pliers or with a durable pin.
- Make sure the gears are turning freely
- Check if the motor gear is aligned and tightened with the grub screw against the flat part of the motor axis
Jammed PTFE tube
While checking the extruder gears, take a look at the PTFE tube as well and make sure there is no debris in it that would prevent the filament from being loaded properly. To inspect the PTFE tube, open the extruder idler door.
Verify, whether the nozzle is properly assembled into the heater block:
- see if the heater block and the nozzle are not crooked
- is there a space between the nozzle head and the heater block as it should be?
Please follow this article to clean your hotend, as the hotend might be clogged. If you don't manage to clean clog, you would have to take out the hotend from the extruder, disassemble it completely, clean it thoroughly and apply some extra thermal paste on the heatbeak before assembling the hotend back together.