Stringing Issues

I know they are different printers, but I’m seeing a lot more stringing on my A1 Mini when compared to the X1C, P1P and P1S, This is using the same model and exact same roll of filament.

I’ve run retraction towers which did indicate needing more retraction, but the final print still doesn’t look quite right.

This is mainly happening on prints with more intricate details on the top surface where there is more jumping around (where you would typically see some stringing). However, it still prints perfect without a single string on the other Bambu Lab printers.

Any suggestions?

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Same issue here - I have a P1S and zero issues — I have run flow calibration, retraction tower, temperature tower and still have stringing - following thread - thanks

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Glad I’m not the only one because I feel like I’m going crazy.

Print quality in general is quite far off the X1C. I know one is a budget printer and one is a flagship, but I think the quality gap can be reduced. A heap of ringing on the A1 compared to the X1C when printing the same model is another example.

Something weird that I found was running the flow calibration on a specific silk PLA filament calibrated with my X1C. It has a flow ratio of 0.96. The exact same filament calibrated on the A1 Mini shows around -15 being the best flow during the test, meaning the ratio is around 0.82. Seems like a massive discrepancy? I’ve run it multiple times with the same results.

I’ve calibrated 50+ filaments on the X1C and never seen below around 0.95. And being the exact same filament (literally the same roll) being 0.82 is odd which makes me think something else is at play here?

An actual print of this flow level had pretty ordinary results. Definitely not an improvement from using 0.96 on the A1.

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let me know if you guys figure out settings to use as i’m having issues as well. it started out pretty good and as time went on the stringing got worse … i changed filament to brand new and still having issues

I’ve encountered filament debris in the extruder gears of every A1 Mini I’ve worked with. The simplest way to inspect this is by unscrewing the filament cutter arm and checking from the side. This gives you a clear view of the driving side. The other side, which isn’t accessible this way, is just a smooth assist wheel and usually doesn’t have issues. Cleaning out the debris definitely improved my results.

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I have not tried iChris suggestion to clean out extruder gears but I will — thank you as I have not had to do this on my P1S yet and I did not want to do that quite yet… but I will.

I spent all day yesterday working on a stringing test model. I changed speed, retraction settings, etc. I have ironed it out to where I am much happier with my detailed models on my A1Mini.

PLA and PLA+ Filament only:

  • Temp is between 220 and 225
  • Retraction settings for A1 Mini 0.4 nozzle
    • Retraction length 1.1
    • Zhop when retracting ( use either 0.0 or 0.2 )
    • Retraction speed 35
    • Deretraction speed 30
    • Retract on layer change (unchecked)
    • Wipe while retracting (checked)
  • Under Filament settings
    • I have found that Max volumetric speed between 20 - 22 works better
  • I have Avoid crossing walls option (checked)
  • Other layer speeds
    • Outer wall 200
    • Inner wall 200
    • Sparse infill 270
    • Internal solid infill 250
    • Top surface 200
  • Travel speed is 200
  • Acceleration speeds
    • Normal printing 1000
    • First layer 500
    • Outer wall 700
    • Inner wall 0
    • Top surface 150

Note: See if this helps and then try to increase speeds and see if you maintain better results. This is what has helped me print the models I need and I really hope this helps others out there - let me know and we can continue to work together to get dialed in. Stay safe.

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After how long are you seeing debris? My issues started maybe 1 week after getting the A1, so surely not that quickly? Seems like a design flaw if so.

It was about a week, maybe two. But seems to be fixed now that I cleaned it. Not really sure what happened there.

Thanks for listing your settings! In particular, I will give the retraction settings a go.

Are your acceleration settings severely slowing down your prints? The defaults are 5-10x your settings.

I’m all for slowing down prints for quality, but the key reason I have invested into the Bambu ecosystem is to print quality as fast as possible.

Also, are you using the default stainless steel nozzle, or the hardened steel? Not sure if there will be variations in results, but worth noting.

Interesting! I have a second A1 arriving Monday so I might just run identical prints side by side first to get some kind of comparison. Then I’ll have a clean and see what changes.

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Cool, let us know how that is going!

Btw, I did not see any difference between the stainless and hardened steel nozzles in any of my prints.

Yes, it is the stainless steel nozzle. I ordered the 0.4 hardened steel — just waiting to receive and try it out. But someone else said not a difference. And yes, not too much loss in time but definitely need to run the A1 slower than my P1S. I probably will stick to just getting more P1S printers in the future but the A1 Mini is better than any of my other bed slingers :slight_smile:

Update - I received the 0.4 Hardened nozzle - swapped it into my A1 Mini and printed same models and they are absolutely perfect - no stringing !!! The quality is now as good as my P1S. I am sooooo happy… maybe the higher heat for my PLA+ is not for the regular stainless steel nozzle… I highly recommend the hardened steel Nozzle… anyway, I just wanted to update the thread with this info.

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try a cold pull on the old nozzle, if you ever get around to trying it again. If nothing comes out, it was probably a quality control issue.

@Ssinger804
Could it be that the new nozzle works well, not because it is hardened but rather because it is new and the old one was damaged, therefore causing stringing ?

Late to the party, but I’m seeing the exact same with my new A1 vs my P1S. Same prints, same filament. Guessing its issue with the A1 series extruder or tuning Hopefully it gets fixed soon.

And what are the results of comparing two A1 minis? And first of all about what level of stringing are we talking about? In general I have some stringing that isn’t problematic at all until I printed some fine details figurines. Print this one https://www.printables.com/pl/model/77917-wizard-male-no-supports-needed at 0.08 layer , standard speed, normal not touched settings. I can tell that stringing and oozing showed up about week after using A1 mini and unpacking esun spools. Then I dried filament , printed with lower temperature of 208 and I had less stringing then on second filament that was dried for less time. Probably some of the moisture will stay in filament anyway.

interesting! maybe we can make a wiper type like the extruders of TPU once haad!
https://www.3printr.com/flexion-extruder-perfect-extruder-flexible-filament-5041341/

It’s better to not fix anything that isn’t broken. I’m skeptical if it is the reason for stringing. I’ve printed two figurines with differently handled PLA+ filaments from Esun and the longer dried one behaves significantly better. How much debris would there have to be to be able to constantly add to currently fed filament or to make uneven feed? It would have to be a lot of it. I’ve just opened mine and there was literally nothing there.

I have been having stringing issues on my a1 combo it’s so annoying I have even used a fresh spool and I dried one and stil no luck