How to remove filament from the AMS Bowden tube after spool ran empty?

Hi all,

So yesterday I printed a large set of models and the filament on my BASF Ultrafuse Pro1 ran out. I was notified of this via the app and tried resuming with a different spool but received error messages.

When I came home and tried the same procedure manually via the touch panel, the AMS tried retracting the filament remnant within the bowden tube, with the empty spool in the AMS running wild for about 2 minutes - then a red LED appeared and it stopped spinning.

Apparently the rear motor on the AMS doesn’t feed the filament remnant back into the AMS - but how do I go about removing this manually?

Thanks for your help, it is really appreciated.

You can’t do this manually. What usually happens is that if the filament end runs past the AMS feeder sensor but hasn’t run out past the extruder sensor, the extruder will keep extruding filament until it does. (I’ve complained that it doesn’t dump the blob often enough, though.) What kind of error messages did you get? I have done this swap successfully.

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I don’t recall the exact error message I received tbh and I have previously swapped from one spool to the other successfully.

If I can’t remove the filament length currently stuck within the Bowden tube manually, how else would I do it?

Can you explain in which areas the filament is stuck (from - to)?
In the worst case you will have to disassemble the AMS to reach the tubes under the spools. But I couldn’t really understand where it is stuck to be honest.


Can you see the filament in the PTFE tube just before it enters the extruder? If so you can undo this PTFE coupler by pushing down on the blue ring and pulling the tube away from the machine. Then remove the filament from within the tube. Let me know if there is even less filament than this left and I’ll tell you what to do just above the extruder to get the strand out but do this first.

In the bambu wiki there is a instruction.
You need loose two screws inside the ams. Then unplug the ptfe in the back and disconnect the ams. After that you can carefully pull out the inner Ams. This is connected with 2 cables to the outer ams. The cables are not very long and tiny. So careful! You can disconnect the two cables and have full access to the inner ams. There you can disconnect the ptfe from your ams slot and you should be able to remove the filament

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Fantastic, thank you!

I was hoping for a non-invasive fix but this will do just fine and only hasten the switch to my Hydra parts for the AMS.

EDIT: do you perchance have a link to the relevant wiki entry or a keyword I could use to find it?

I use a y splitter in its place but other than that yes, I can reach the filament remnant from that side.

@Christian
Its other end is stuck somewhere inside the AMS, but past the first stage feeders and held tight by the gears somewhere inside the AMS.

I will follow @swateinheit’s advice (just noticed the user name and giggled) and take apart the AMS to get to where it’s stuck.

Thank you for your advice!

https://wiki.bambulab.com/en/x1/troubleshooting/filament-breaks-in-path

The step 2 Video helped me.