X1 Carbon with AMS not retracting a specific PLA

So far my AMS is doing a great job at retracting the filament into the machine after prints finish, getting ready for the next print.

When I use a Matterhackers PLA, the print finishes and does a great job but at the 100% (almost) I get a clog message saying it can’t be retracted into the AMS. After I cancel the done print, I can’t get it to retract but if I simply pop off the quick fitting on the back the printer, the AMS will suck it right up. I don’t have to clean the hotend or anything before the next print. It’s a pretty normal PLA and doesn’t have extra friction.

Looking for a way troubleshoot it.
Thanks!

There are only so many things that influence the pull back.

A major part is friction of the filament inside the PTFE tubes and other components. Make sure all PTFE tubes on AMS and the printer are all fully inserted, sometimes they become loose a bit during transport or aren’t fully inserted at factory.

Second is the spool itself. Is it loosely enough to spin freely? Some spools are wider then other and do not fit the AMS, you would need to rewind it to a fitting spool. Also very large and full spools might be hindered by the rolled up filament pressing against the housing in front of it.

In the end, nearly all retreact issues come back to too much friction in the system, but there are plenty of reasons for friction, from a stuck part, a broken off filament, too rough filament etc. And often they simply add up till things do not work.

Might have a look at these little things, they are supposed to help a bit with friction.

https://www.printables.com/de/model/343728-bambu-ams-feeder-button

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I have a look at the link and check all of the PTFE tubes. First comment on the link is that Bambu Labs voids the warranty if you use those. I don’t mind doing that but would like to also exhaust troubleshooting efforts before voiding the warranty.

The parts print perfect with the filament in the AMS, spins and retractions. The only issue is the large retraction at the end to remove the filament from the printer.

I don’t think that support agent realizes what it is. The actual feeder isn’t being modified, the Feeder Button is just a bracket that sits on top of the funnel that keeps the filament going straight down into the funnel, instead of doing it at an angle (which appears to be the problem, the filament is catching on something).

Exact same issue myself and others were having, that was fixed by the Feeder Button. Lots more discussion on it here. and some more discussion on it here.

Did you guys have problems with all filaments or just some? The BL PLA works fine it just the Matterhackers that is having this issue.

Regardless, I agree with you on the simplicity of the button and it’s next on my list to print.

I tried some PLA-Brands

Working Brands

Seemed to mostly abrasive filaments causing the problem. But it’s weird because, for me at least, on some filaments it only happened some of the time. So my best educated guess is that the abrasive filaments I am using that were giving me trouble are stiffer and not as flexible as standard filaments. If these stiffer filaments just happen to be at the edge of the roll when it’s time to retract, they are at a weird angle and the AMS can’t retract. This is why I think I’m able to manually pull it out with ease from the rear after releasing the tube from the AMS hub.

If the filament is in the middle of the spool, it might not be at a weird angle and it seems to retract fine when color switching.

The Feeder Buttons seem to keep the stiff filaments going straight down into the funnel, and fix the problem completely.

But again, since I haven’t actually been able to catch the AMS at the exact moment it errors, I’m only speculating. If I had to guess in your situation, the Matterhackers filament might be a little stiffer (or maybe older, with different properties?) than standard PLA, which is why it’s acting differently from you. Would be interesting to see if the Feeder Buttons fix your problem too.

So I printed the Feeder Button and I still get the issue in the picture I’ve include. If I heat up the hotend and push the manual retract button once or twice and then hit the retry on the print at 99% the automated retract will then work and my print goes to 100% (successful) and the print bed drops to the bottom as expected.

I had this problem and my 1st stage feeder seemed to be defect. Now i got a new one from Bambu and it works fine.

That’s a great point, this is the first filament I’ve had in this slot of the AMS. Let me move it to another slot and see if the problem persists. If it does NOT persist did you contact AMS for a replacement or just buy one? What’s the best way to get in contact with them to open a ticket?

I got a new one from Bambulab via ticket-system. They wanted a few videos to see an hear what the feeder is doing. After they checked it, the sended me a new one.

You might try replacing the cutter blade in the head. It needs to be sharp to cut the filament before retracting.

I also pitched a short roll I got as a freebie from the maker when I bought my X1C. It must have been old or something. I had constant problems with that filament from the start and I didn’t even use it. I just had it loaded in an AMS. It constantly broke and jammed the AMS on start-up. It broke into little pieces. I must have disassembled the AMS 10 times to get the pieces out. I took it off the spool and threw it in the garbage. I’ve been buying Sunlu ever since. I could have reused the liner and tag, but I don’t use green filament. :face_vomiting:

I got the same issue with my new P1S combo. Specific filament, in my case Bambu PLA Basic Black would not retract back to AMS, generating error message. It was recurring for many print attempts. The problem seems to be on AMS side, as filament is successfully disconnected from printing head. And also no such problem from other Bambu filaments I have, from the same PLA Basic line and using the same AMS slots. All tested filaments are fresh, stored in original sealed bags…