Failing to retract filament, how to cut again?

Bambu Lab Software Bambu Firmware
1

I have had a couple of multicolour prints where the filament has failed to retract to the AMS. When I retry it appears the nozzle is reheated and the retraction is retried but there is no attempt to cut the filament. If I cancel, the print and unload the filament, it cuts and then retracts without issue. Is there a way to force a retry of the cut part if retraction fails part way through the print. If not please add this as an enhancement to the firmware :slightly_smiling_face:

Many thanks
Steve

2

Hey Steve,
Have you tried manually pushing the cutter lever and then using the “retry” option? I’m curious if this would allow it to pull back and the filament and it’s just not telling it to do the action like it should?

In my experience there are a couple of other reasons why this might fail as well.

  • A piece of filament broke off in a PTFE tube somewhere and can’t be moved by one of the interstitial gears or is too short to be reached for some reason
  • The spool for the material in question is getting pinched or bound up somewhere (opening the AMS lid will usually alleviate this
  • The spool is only slightly pinched or bound up like above, and overworking the AMS motors that run that slot

… and probably some other things I’m forgetting…

1 Like
3

Thank you for your reply. Really helpful. I hadn’t tried manually pushing the cutter will definitely do that next time I see the issue. I did open the AMS lid and so I don’t think a trapped spool was the issue.

Thanks again!

4

Hi Steve, any updates?

5

I’ve had a couple more incidents, a blunt cutter was the cause once - manually pressed the cutter. The other - there was a piece of broken filament trapped in the AMS.