After printing with the carbon fibre PLA that came with my Bambu Lab X1C (PLA-CF), I found a clogged nozzle early into the print, maybe 15 minute after it started (I left the printer after starting the print and then came back to it). At first I thought it was a clogged nozzle, so I unclogged it. Unfortunately, the filament is stuck above the filament cutter in the hotend. I am not able to unload the filament as I can not pull it back nor push it forward anymore (even with the nozzle removed and the filament heated). I am thinking about removing the PTFE tube above the hotend now but have never done it on my X1C
How should I proceed to unclog the Filament?
background info: I was printing at 230° Nozzle temperature and 55° bed temperature with the front window closed using a 0.4mm Micro-Swiss Nozzle. Having the window closed is my guess on what caused the issue. Furtehrmore, It seems at first glance the worn out filament cutter could not swiftly cut the PLA-CF anymore. I removed the nozzle while filament was hot and tried to clean it out. The filament cutter has been replaced with a new one and it felt like the stuck filament could be cut by it. I was able to remove the clogged filament below the filament cutter and get the nozzle free.
Common issue. You let the build chamber get too hot. The filament was getting over it’s glass reflow temperature (when it gets real soft) before it was getting to the extruder.
See the WiKi for instructions on removing and disassembling the extruder to fix your jam. It might be less work than what you ended up doing.
To prevent it from happening in the future, remove the top glass lid and/or open the printer door while printing.
Also, 230 is way high for PLA. It’ll print at 210 or even lower. And running the bed at 55 also adds heat to the build chamber. If you ran a lower extrusion temp and didn’t heat the bed, you might not have an issue even with the lid on and the door closed and the chamber fan off.
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You can treat such a severe heat creep like an extruder clog.
https://wiki.bambulab.com/en/x1/troubleshooting/extruder-clog
Also, to be safe, I have found the hot hex wrench nozzle unclogging to be superior.
My sweet spot for PLA is a chamber temp of 35-39°. For heat creep prone prints (PLA-CF or ironing or many retracts) I stay below 35°C.
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Thank you both for the replies.
I also thought that’s what caused the issue. I stayed at 230° because it was the default for PLA-CF in Bambu Studio but also remember printing it with 210° in the past when I confused it with regular PLA once and didn’t have an issue.
Will try using a cold plate for future prints. This one was on a smooth hot plate because I didn’t want the textured plate on that particular print.
Will check the wiki and keep you updated.
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by the way what would you suggest for retraction distance and speed? I once upped the default distance to 0.85mm and the speed to 35 or even 40mm/s after having some oozing problems
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Oozing problems are caused by moisture in the filament. Dry your filament out before printing with it and it won’t ooze. Default retraction settings should work perfectly with pretty much every filament there is. I’ve been FDM printing since around 2010 and have never messed with retraction to get a good print. But my filament spends 24 hours in the dryer before going on to the printer. 
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I am usually good with the defaults. But feel free to experiment.
Bambu recommends retraction legths between 0.8 and 1.4mm with retraction speeds of 30 to 60mm/s for both PETG-HF and Translucent.
The printer is up and running again.
I had to disassemble the extruder to unclog it. Images attached
Looking back, next to the chamber temperature, I think this experimental setting (that was enabled by default iirc) also played a role in clogging my extruder.
Thanks to everyone for the support
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