Cannot load filament - Clicking noise

Bambu Lab H2 Series
1

Hi folks,

This started with broken filament in my idler yesterday evening. I fixed that but this morning the printer has stopped again mid-print. I unloaded the filament but it won’t load again.

I cannot load filament on my left extruder. The filament is pushed through the ptfe tube and when it reaches the toolhead there is a clicking noise (Which Im guessing is the servo motors trying to pull it through).

Has anyone see this before? Any ideas?

What have I tried:

  • Confirmed that a piece of filament passes easily through the idler when the toolhead was stripped.
  • Swapped AMS-HT and AMS2. Both fail on the left extruder. Both work fine on the right extruder.
  • Changed the ptfe tubing.
  • Stripped the toolhead again and checked for filament around the gear and in the idlers.
  • Replaced the dual extruder gear.
  • Tried different filaments.
  • Raised a support ticket.

I have a spare extruder servo motor, but the right extruder is working fine so I dont think there is any point stripping the toolhead again to replace that. :confused:

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2

Your nozzle is probably clogged.

2 Likes
3

Fixed! There was a blockage in the black connector inside the filament guide! Thanks.

4

In the future, a good way to test for this is as follows…

  1. remove ptfe tubing from affected side of print head.

  2. remove nozzle from affected side of print head.

  3. set active nozzle to NON-affected nozzle. This is to get the extruder gear clear of affected side.

  4. try by hand to insert a length of pla or petg filament through the affected side of the print head. Try to insert from top to bottom and also bottom to top. You may need to twist a little and it helps to round off or chamfer the filament sample.

If you are able to get the filament through, then you have ruled out the print head assembly as the culprit. If it gets stuck, then make note of how far the filament can be inserted before getting stuck and use that length to determine where in the print head the issue is.

BTW, this usually happens when a low temp filament is left loaded in one side of the print head while the other nozzle is printing a high temp filament. This can cause the low temp filament to get hot enough to deform/bulge and no longer fit through the rest of the print head path or nozzle throat. Avoid by unloading any low temp filament from the inactive side before starting a high temp print (ABS for example).

1 Like