Switched to 0.8mm nozzle recently and started getting popping sounds, as though filament is wet. Tried switching between filaments, dried everything for >6h in a filament drier, popping still present. Switched back to 0.4mm nozzle - popping disappeared.
Anyone else had issues like this with the 0.8mm nozzle? I’m wondering if I got a bad unit or if the default 0.8 profile is not set up correctly (e.g. retraction too high causing air pockets in the nozzle).
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I don’t have the 0.8mm nozzle, but I suggest manually extruding and retracting for debugging if there is a faulty nozzle or settings. If the pop continues, increase the temperature slightly. If it persists, it is likely to have some issues in the nozzle, filament, etc…
If not, you need to calibrate the filament. Typically, popping is associated with wet filament, but it can also be other things, such as extruding problems related to settings. My experience with the 0.6mm nozzle shows that BL profiles are not as optimized as for the 0.4mm nozzle.
A few questions: Did you use the same spool with .8 and .4 mm nozzles? Did you calibrate? Did you set the 0.8mm nozzle in the printer?
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May just be gear/motor lash. If youre trying to print fast with that nozzle, your extruder is really working hard and fast to move enough filament through it. I know going from .4 to .6, the slicer cuts the speed back by about half.
Is the noise during retraction? or right before a head movement? or random? does it pop while printing long straight lines?
Im probably wrong, but its a possibility. Another one is you coukd have a tiny piece of filament in there. Ive had about 5 or 6 small filament breaks in the extruder. Im honestly suprised i havnt stripped any screws yet.
Depending on what the filament type is, and how wet it was to being with, 6 hours may not have been anything near enough time for drying. The filament is feeding in to the hot-end 4x faster with a 0.8mm nozzle than with a 0.4mm nozzle. Wet filament is transporting a lot more moisture in to the hot end at a higher rate, which could easily explain why it’s not popping at 0.4mm. It probably still is, but at the much slower rate pressure is building and being released it’s not loud enough to be noticeable.
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@JayZay
Yes it’s the same spools (tried multiple), yes I calibrated (both manual and automatic where 0.8mm is supported), yes I used the default 0.8 profile when I switched to the 0.8mm nozzle.
@StreetSports
I have tried to slow the print down to <30mm/s. I have tried limiting volumetric flow rate to 5mm3/s. I have tried cold pulling. I am leaning towards it being a settings issue rather than a bad nozzle, because so far I’ve been unable to replicate the popping sound when extruding manually via the touchscreen. It just seems very odd that BL didn’t bother making sure their default settings can at least print without bubbles, considering how relatively well their 0.4 profiles are optimised. And the fact I can’t replicate it when extruding manually could have other explanations, it does not rule out a bad nozzle completely. So I would like to hear from someone with experience using BL’s 0.8mm nozzle/profile before I go on a wild goose chase.
extruding via the touch screen is way slower than the normal retract. If there was gear lash, you wouldnt hear it from unload/load actions. If you feel ots software based, just go back to factory settings on everything.
If you have bubbles your filament is wet. seems like 80% of random issues are just wet filament. Unless everybody running that nozzle is getting popping.
Everything was already set to defaults before I started calibration. I’m saying the default values are not right.
No, if I have bubbles all it means is there is air in the molten filament. There can be many causes for this, not only wet filament. For example, wrong retraction is a known cause. As I explained above, wet filament is not the cause in this case.
Easy test then. Turn off retraction.
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Brilliant! No more popping sound, though the oozing is a bit much I think. But now I know how to proceed, thank you!
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Which setting exactly have you switched off?
Bambu Lab X1 Carbon 0.8 nozzle → Edit preset → Extruder → Retraction length
Changed from 3mm (default), first to 0mm (off), then adjusted to 0.4mm.
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I’m having the exact same issue with a 0.6 nozzle, I’m 100% sure the filament is dry. Will do a retraction test to see if fixes the issue.
If it’s retraction causing the issue you can find the override settings for it in the filament settings under the settings override tab, I recommend changing it here and not in the printer settings at the top as the printer settings will affect all of your prints and not just the one filament causing the issue l.
Check the retraction box and input your value. If it’s PETG you may need to reduce to around 0.2mm to 1mm depending on nozzle size and print size. Also you may find playing with the retraction and deretraction speed helpful for final tuning.
A quick way to check is set it to 0mm and see if you have the same issue, you will notice that it will be very oozy though as there is no retraction.
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@oddsandsods thank you for your reply, I’m aware of the filament settings override.
Both Bambulab PETG HF and Spectrum PLA Premium are causing the same issue, I have changed both to 0.4 (did the Orca retraction test first) and the issue is now gone.
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After spending a day on trying out different settings and prints, this was it… The pop was always after the same amount of filament length, same frequency. So I was sure it’s not about it being wet or other issue.