Filament can't be returned

Bambu Lab P Series Troubleshooting
1

Since a couple of weeks I have issues with the pull back (or sometimes) the loading of the filament (AMS 1). To be more concrete, what happens sometimes:

  • New role added, but feeder unit can’t pull it
  • Print was successful, but filament can’t be returned (printing error)
  • Role in AMS struggles (push and pull back without really moving the filament) at filament changes

I have dismantled the AMS already. First I thought the feeder unit of the AMS slot 4 is damaged, but I even maintained the small spring (recognition of filament is inserted) and I doubt that the error is there. In addition also other slots, at least AMS slot 2 shows the same issues. So I am currently more at the AMS internal hub unit, but it also looks fine. As it is a quite costly spare part, I don’t want to buy it just on suspicion.

I have also checked the extruder of the hotend, but it was changed a few months ago and can’t be the root cause for the non-loading of the filament (must be an AMS issue).

I am thankful for any hints!

2

This bedeviled me recently. Eventually I realized the affected spools had slipped sideways a little and jammed between the driving wheel and the side of the spool slot. Check your spools for free rotation. You may only have to re-center them.

3

Good hint, but I also have checked this and the roles where the spools a lying on.

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4

Ugh, I’m sorry. I really hoped it would be that simple. Good luck, and I’ll be following this thread in hopes of learning more.

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5

If you have a lot of hours on the unit, you may try replacing the PTFE tubes. Extra friction along the lines adds up in wierd ways, and PTFE does wear. I’d also try to put some eyeballs on your HUB during a change, and make sure the filament’s end isn’t getting hooked in the hub somewhere.

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6

That’s a good hint. I have around 3’000 hours of printing with a lot of filament changes. I have some PTFE tube here, so I will replace this as a first step. Thank you!