Clogging issues with 0.25 mm nozzle – clicking and filament load/unload during first layers
Hi everyone,
I’m having serious trouble printing with the 0.25 mm nozzle on my Prusa XL.
The print starts normally, but within the first few layers, the printer tries to unload and reload the filament, as if a clog has occurred. I also hear the typical clicking sound from the extruder, which clearly indicates too much back pressure.
I’ve already tested several filament brands, and now I’m using Prusament PLA, known for its excellent tolerance and quality.
Current settings:
Nozzle: 0.25 mm
Layer height: 0.15 mm
Volumetric flow limited to 3 mm³/s
Speed limited to 35 mm/s
Extrusion multiplier down to 0.6
Multiple nozzles tested and replaced
Despite all of this, the clog happens right after the print begins – not while idle or switching tools, but during normal extrusion.
Is anyone else experiencing similar issues with 0.25 mm nozzles on the XL? Any official suggestions from Prusa on how to use this nozzle size reliably?
I’d really appreciate any help – I’m struggling to make this work at all.
Thanks in advance! –Tom
Best Answer by JoanTabb:
what filament are you using? 'filled' filaments will block small nozzles!
have you tried reducing retraction lengths?
Are you using an enclosure? PLA in a closed enclosure, can cause blockages
What is the ambient temperature in the area of the extruder?
high temperatures can cause heat creep and blockages
regards Joan
RE: Clogging issues with 0.25 mm nozzle – clicking and filament load/unload during first layers
what filament are you using? 'filled' filaments will block small nozzles!
have you tried reducing retraction lengths?
Are you using an enclosure? PLA in a closed enclosure, can cause blockages
What is the ambient temperature in the area of the extruder?
high temperatures can cause heat creep and blockages
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Clogging issues with 0.25 mm nozzle – clicking and filament load/unload during first layers
I’m using standard PLA from Prusa – no glitter, no silk, nothing fancy.
Retraction is already reduced to 0.4 mm.
Yes, I do use an enclosure.
I’ve tried temperatures from 210 to 235 °C already.
That’s a great point about the enclosure – I’ll try keeping it open now and see if that helps. Thanks!
RE: Clogging issues with 0.25 mm nozzle – clicking and filament load/unload during first layers
I printed with the enclosure open, using 215 °C on the nozzle and 50 °C on the bed, while the enclosure fan was running.
It definitely worked better than before, but unfortunately, I'm still getting about two clogs per layer.
RE: Clogging issues with 0.25 mm nozzle – clicking and filament load/unload during first layers
It's a case of suck it and see
Any chance of blowing cool air into the enclosure with a fan?
Could you try 0.2mm retraction, or no retraction?
Have you tried printing with stuck filament detection, turned off?
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Clogging issues with 0.25 mm nozzle – clicking and filament load/unload during first layers
Thanks again for the suggestions!
I had all fans running at 100% inside the enclosure and even added a Dyson fan blowing cool air into it – unfortunately, it didn’t help.
I also tried retraction settings down to 0.2 mm and even 0.0, but the nozzle still gets clogged.
I tested the exact same print on my first Prusa XL without an enclosure, and it's been printing flawlessly for over two hour now.
Now I’m seriously wondering: do I have to convert all my enclosed XLs into open XLs just to get reliable prints with the 0.25 mm nozzles?
RE: Clogging issues with 0.25 mm nozzle – clicking and filament load/unload during first layers
have you very low temperature extrusion with the 0.25mm nozzle and PLA? maybe 180C to 190C?
have you tried PETG with the 0.25 nozzle?
PETG is less prone to heat creep?
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Clogging issues with 0.25 mm nozzle – clicking and filament load/unload during first layers
Yes, I already tried printing at 190 °C, but the nozzle clogged even before the print actually started.
I assume PETG would have the same issue, since it usually requires even higher temperatures, which could make heat creep worse.
So, since everything worked fine on my first XL without an enclosure, I removed the enclosure from my third XL as well – and it worked much better. Out of 10 layers, I only had 4 clogs, which is a big improvement.
Everything else was basically the same as on the first printer, so I swapped the nozzle again – and surprisingly: it worked! There was one minor clog during the first layer, but that’s probably just a Z-axis calibration issue.
Conclusion:
It’s very likely that the enclosure setup isn’t ideal for such a fine nozzle like 0.25 mm. Why it didn’t work when the enclosure was open and I was blowing cool air in with a Dyson? No idea. 😅
RE: Clogging issues with 0.25 mm nozzle – clicking and filament load/unload during first layers
Glad to hear that you resolved the issue,
odd that the Dyson didn't help!
PETG has a higher glass transition temperature so you may get different results.
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK