Bought my P1S a few months ago and I’ve gotten my AMS recently and was printing fine for a few days. Last print, though, I’ve encountered an extruder clog where I can’t seem to find similar cases online. So, let me present it here.
Issue:
Extruder clog
When:
After prime tower wipe. So, the filament change, purge and prime tower wipe was successful. When it then resumes the print, it clogs.
Print head in a stuck state - notice in the background, the prime tower has RED filament, indicating that it had successfully loaded the filament and started printing with it, but stuck when it tried to resume:
Hypothesis:
After priming the prime tower, there’s a retraction that happened that pulled the filament back too far and too fast and re-extruded when it’s still in soft, melted state, causing it to bend at the exit outlet when it hits it.
Questions:
Any ideas as to what else may have caused this?
How can I solve this issue?
If it’s retraction settings, is there a retraction setting that I can tweak specifically for transitioning between priming and resuming the print?
I have only had a single clog to date which was my own fault due to dissimilar material printing without having checked the temps. So not really able to speculate on root causes other than to recommend to also look closely at the nozzle itself.
Retraction settings can be changed in the material cards in the Bambu slicer (3rd tab from the left).
I had problems especially with the filament changes as well. I struggled with this for about 5 days and found the following:
a higher temperature is used to purge the nozzle than to print. As far as I could understand, it is related to the maximum temperature that is specified for each filament in the filament settings.
since there is clearly filament deformation in the extruder and the extruder is also very warm when removed directly after clogging, too much heat is rising into the extruder.
there is a cooling body with a fan under the extruder. Therefore, not so much heat should accumulate above it that the filament deforms.
So the only conclusion I could come to was that the cooling in the print head is insufficient. I am not the only one who came across this. There are several solutions to this. One is to break out the printhead cover widely at the sides, so that the airflow at the heat sink is improved. Another solution, which also helps quite often and is preferred by many users, is to leave the printer open as soon as certain filament is printed (basically any filament that softens at relatively low temperatures).
My solution is to install an auxiliary fan that feeds cool air from outside to the print head during filament changes and is only switched on then.
@KanneKaffe Thanks for taking the time with a detailed response. It’s deeply appreciated
What you’ve described aligns well with the symptoms presented in the clogged extruder - the bent filament. I’ll see if there’s a way for me to improve the cooling during the change and observe its effect.
What I’m not quite sure about though is the rationale behind such a huge retraction - the whole length of the nozzle between priming and resuming print.
Does it really occur during the filament change? And does the printer otherwise print properly? And after how long does it occur? Already in the first few minutes or only after a longer period of time? I print smaller objects with filament changes, so if the filament is changed every two minutes, for example, but the problem does not occur until, say, the tenth change, it should very clearly be the heat development upwards in the print head. This was the case with my printer when it always changed between PETG and PLA because PLA was the support material.
In your case, the problem obviously does not occur directly during the change (filament cannot be withdrawn or filament cannot be extruded after the last change, I think there is an extra error message for both cases). Nevertheless, in your case it may also be due to insufficient cooling in the print head. When switching between PETG and PLA, I can darkly remember that there were then also problems with the extrusion during printing, but after successfully changing the filament. But I have not reviewed this specific case any further. I would do it again so as not to say anything wrong, but I can’t do that again until tomorrow; until tonight the printer is busy at my place.
Note: All my filaments across 4 slots are the same Polyterra PLAs. So, there’s no material type change. Just color change.
1. Does it really occur during the filament change?
Yes - only during filament change and very importantly, after priming tower, which indicated that extruded and printed correctly before it resumes printing
2. And does the printer otherwise print properly?
Yes - single filament, same slot/filament via AMS prints perfectly
3. And after how long does it occur?
This was a really small 10m print. The filament change occurs about halfway through, so between 5-6 mins into the print and this is the first filament change. If referring to the AMS itself, I’ve only got it for about 2 weeks now.
4. Already in the first few minutes or only after a longer period of time?
As #3 above, this happened just a few mins into a small print. I need to test on a larger print to see if the same thing happens, although I really don’t look forward to disassembling it again to remove the clog
I love your response @visualdensity! Something completely different. Did you perhaps set too high a retraction value on the filament? I can’t imagine that because you don’t actually need to change that and it would be the last thing I would do for any reason (because of issues like that).
This is EXACTLY my same issue. Brand new AMS. Been printing with my P1P successfully for most of this year.
With a multi-color print, the first color prints perfectly. For the second color, the AMS successfully switches to the 2nd color. It prints a prime tower just fine, and then as soon as it resumes the normal print, the extruder clogs and then sits there and spins. I have to take apart the extruder to remove a tiny blob of filament.
Bambu support says this
2023-12-02 04:32:53
Hello,
After a thorough review, we couldn’t identify any abnormalities in the system. To further troubleshoot the issue, we recommend the following steps:
Check G-code for Fans: Please refer to the guide attached at Guide Link and inspect the G-code for the fans. Ensure that they align with the provided guidelines.
Reslice in Bambuy Studio: Reslice the model in Bambuy Studio and confirm that the fans are enabled in the filament profile. If the problem persists, proceed to the next step.
Try a New SD Card: Format a new SD card to FAT32 and attempt the print again. Sometimes, issues may arise from the SD card. Check if the problem still occurs with the new card.
If the issue persists, kindly provide us with more information:
Share a copy of the .3mf file used for the print.
Alternatively, open the rear of the printer and double-check all connections to ensure they appear normal.
i too have this issue clogged up during a print went to change the filament and bang i am sure mine is due to non Bambu branded pla is it possible to replace this part or not
Something completely different. Did you perhaps set too high a retraction value on the filament? I can’t imagine that because you don’t actually need to change that and it would be the last thing I would do for any reason (because of issues like that).