Printer continues when it cannot pull filament

One of the most significant design flaws of the Bambu Lab X1C and P1S is their inability to effectively detect filament issues during printing. We’ve all experienced filament spools, whether new or used, not unwinding properly and becoming tangled. Unfortunately, this happens far too often.

The real problem arises when the filament gets tangled, and the extruder can no longer pull it through. Instead of stopping and alerting the user, the printer continues operating as if filament is still being extruded. This oversight has led to countless failed prints, wasting time and material, as the printer carries on as though nothing is wrong.

This lack of a filament sensing mechanism to detect such issues is incredibly frustrating and should be addressed in future designs or updates. A simple warning system could save users significant hassle and prevent unnecessary failures.

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Where is it getting tangled for you? Normally if the AMS can’t advance filament it will retract it all the way back to the first stage feeder and try a few times to get it back to the print head. If it can’t it will give an error and pause the print.

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Thank you for the response. The majority of the time this happens is when the spool is not loaded into the AMS, however, there have been occasions where this has happened while pulling from the AMS as well. Whether I am using my P1S or X1C. I also have two AMS Units. And yes, usually if it gets tangled in the AMS, I get the “motor overload/red led flashing” and the printing pauses, Either way, I firmly believe that if the extruder is not pulling filament, the printing should never continue. If this scenario has never been addressed or considered, I would have to say that this is a design flaw. Other than staring at the printer and spool for hours to stop printing manually, what would you suggest? :crazy_face:

I’m sorry, you’re absolutely right. I wasn’t even thinking about an external spool. I think they’ve addressed this better in the A1 series. I believe the spring loaded filament sensor right about the tool head would stop this. Now I know that won’t help with the X1/P1 printers. It would be awesome if someday they put out some upgrades for the X1/P1s that used the new tech they put in the A1s… but with an even newer model coming out next year I don’t think it’ll happen.

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The only tangles/failure to feed that I’ve had were caused by the user. All involved careless handling of the filament or improper mounting of the spool.

I don’t expect the printer designers to overcome my shortcomings. They cannot possibly make a foolproof machine because there will always be a greater fool.

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While portraying a molehill as something the size of Everest.

In two years of X1C printing I have had one filament spool jam because I loaded it in the AMS with it one loop on the spool twisted around another. It jammed and I noticed it before it even started the print.

Fed from an AMS the buffer or hub can detect if the extruder isn’t pulling filament. I would be surprised if it doesn’t do that. I have never had a jam to be able to notice. Without an AMS detection would require additional hardware and IMO it isn’t worth spending anything on a problem that barely exists.

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**“Your response feels unwarranted and dismissive. To suggest that filament tangles or feed issues are solely ‘caused by the user’ oversimplifies the problem and overlooks the realities of manufacturing inconsistencies or system limitations.

\The goal of engineers, designers, and developers is to create systems that account for potential user challenges and minimize the likelihood of failure. In this instance, my suggestion is aimed at addressing a gap in the printer’s design, not belittling its overall capabilities.

If something in my comment was unclear, asking for clarification would have been a more constructive approach than jumping to assumptions. Let’s strive for a productive conversation rather than resorting to unnecessary criticism.”**

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ZiggyP, yours and the previous comments seem so short sighted, However, Thanks for your input, although there clearly is a misunderstanding of my main concern. My point isn’t about how frequently jams occur or how effective the AMS is in detecting some issues—it’s about the lack of detection at the extruder level, especially when the AMS isn’t being used.

Even with careful handling and loading, tangles can still happen, and when they do, the printer currently continues operating as if filament is being extruded. This results in wasted time, material, and failed prints.

A detection mechanism at the extruder would address this, ensuring the printer pauses if filament isn’t feeding properly. It’s not about solving a problem that ‘barely exists,’ but rather about improving reliability and user experience in all scenarios, including those without the AMS.”**

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Thank you for taking the time to actually readthrough the issue at hand, I appreciate your constructive input.

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A very significant design flaw indeed. I was in disbelief when it first happened to me and thought a filament sensor was shot but that was not the case. The fact that this feature is implemented on their lower tier models and not their premium ones is mind boggling.

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This also surprised me. Just now I had a tangle (bambu pla, near end of spool…i dont want to hear how it can happen, ive been down that path).
This is a new P1S, i also have x1c, A1, A1 mini. Print everyday for 5 years, ive seen everything!! The A1 throuhh AMS LITE stops on tangles. I thought the P1S would be as good. BTW im using the rear spool holder as i dont have parts for the AMS yet–shouldnt matter, this machine is designed for loose spool!!
DAMN— my Prusas handled this!! Just glad i was around, though lost an hour of print time. C’mon??

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Yup BS. They’re pretty much forcing you to buy an AMS.