Tips for avoiding nozzle clogging?

Hi All,
I have searched the forum for help on this but did not see much advice. I am seeing repeated clogging during prints. All my printing has been with Snapmaker-supplied PLA so far. I used one reel of black with no clogging issues. I have started a reel of white and printed a temperature tower successfully. I started a bigger print (about 40 hours I think) and the nozzle clogged about halfway through. I cleared the clog with a thin piece of wire (one tip I found in these forums) and printed a calibration cube and a small mechanical part succesfully. Those successful prints represented about 4 hours of work I think. I started another long print and the nozzle clogged again after about 8 hours. Again I could clear it with a piece of wire and I can easily push filament through by hand when the nozzle is above about 190°.

Questions:
1: The hob gear that drives the filament has a bit of PLA debris in it after grinding on stuck filament. Should I be trying to clean that out somehow?

2: Is there anything different about the white PLA compared to the black that would be causing clogging? On the temperature tower I printed I didn’t see much variation in quality between the rungs.

I’m printing at Normal quality with zhop and retraction, a skirt, extra extrusion and slower motion on the first layer. I have tried printing at 200-215° so far with the white PLA.

The PLA reel goes into a dry bag between prints to avoid humidity buildup, and it is not in a dusty area. The packaging for the reel was first opened about 4 days ago.

Any tips will be appreciated!

Hey, your retraction distance is most important.

I would suggest you to 1mm retraction distance.

I would also change the hotend, I had a clogged nozzle too, because of a piece of broken ptfe tube inside the hotend.

Thank you @xchrisd - this is really interesting. I will try retraction distance of 1mm as you said (was 5mm before). I was resisting the step of changing the nozzle as it has so few hours of use on it, but I see your point that there could be another reason to change it.

Thanks again!

Quick update - I started a new print with 1mm retraction distance, and everything went well at first. After about 1 hour the nozzle caused the print to detach from the bed and started dragging it round. I assume my bed is not flat enough to support 1mm retraction distance. I am starting a new print with 1.5mm retract.

Retractuib distance is not your problem
Check if Z-hope is activated

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Hi @Isaac11, thank you for jumping in. I do have zhop activated. “Zhop when retracted” is checked “on” and the distance is set to 1mm.

Thanks again!

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Hi, do you have a photo of the problem? Does the filament clogged inside the module or just around the nozzle?

Hi @Potter, the filament clogged inside the nozzle. I took an overall photo that included the nozzle after one of the fails and you can see the nozzle area in the attached image.

. There was a bit of PLA on the outside of the nozzle but the bottom of the nozzle was clear.

The latest print ran overnight and finished successfully. I think it helped to reduce the retraction distance (the original setting of 5mm must be excessive for PLA) and I have a better understanding of retraction distance vs Z Hop now. Thanks again to all (including @xchrisd and @Isaac11) for lending your expertise.

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This happened to me too. Never had a clog with the SM black PLA, but I did with the white PLA. Using mostly default Fast settings when this happened to me.