Weird PLA Jam  

Active Member

Printing eSun eSilk Silver PLA+, got through the first 5 hours of a 6 hour print then got this jam, I am thinking somehow it for too warm around the extruder?

Posted : 07/11/2019 7:39 am
Estimable Member

Yes, this happens when the ambient temperatures increases beyond a threshold that is specific to the filament you are using. In my case I get these when the ambient temperature gets closer to 30° C and the PLA starts melting before it reaches the hot-end.

If you use an enclosure, remove it. If not, open a window and let in fresh (cool) air. Your troubles should go away quickly after that.

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Posted : 07/11/2019 9:50 am
Active Member


That makes sense, was in an enclosure, ambient was around 35degC.  Reprinted with doors open, no issues.


Posted : 07/11/2019 8:45 pm
Reputable Member

It's not so "weird at all. It's known issue, many users had it already, however nothing is done in this way. The cause is too high room temperature, small travels of extruder and too hot stepper motor. Small travels of filament cause that flow is very small, consequently PLA heats up from the heat of  (again: too hot) stepper motor, becomes soft and jams. How? Simple. Heat from motor travels through it's shaft to extruder gears, which heat up filament. If flow is high then jam won't happen because PLA doesn't have time to heat up. Only when printing details (or small parts) you'll get jam.

I've had a few such jams in the summer. At the end i solved the problem with installing a 5V fan on the top of extruder stepper:

Posted : 08/11/2019 10:43 am
wieman01 liked
Active Member


That makes sense, the issue started when the print transitioned from 0.25 layer height to 0.07 layer height.

Posted : 09/11/2019 12:55 am

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