I have a CR-10 S5. I was very happy with the way it was printing but all of a sudden it cant get past 1 hour of printing without the filament breaking in the extruder. I have caught it in the act, it will be printing fine then the extruder will begin to click. I paused the print which lifts the hot end off the build plate. I can easily pull the filament out of the hot end and the Bowden tube, it will still click in the extruder. I release the clamp on the extruder and pull a few inches of filament through, cut it off and feed it back into the Bowden tube and hotend. Resume the print and it will continue printing fine until the extruder gear starts skipping again (maybe another 10 minutes in).

When I pull the filament out of the Bowden tube after it has jammed I notice the end of the filament closest to the hotend is still nice and round, but as it gets closer to the extruder there are teeth marks in the filament and it is also flat.

  • First few layers go down good - extruder doesn't start clicking until ~ 1 hour into print.
  • I have tried releasing the pressure on the extruder clamp - which leads to the gear slipping on the filament and wearing it away until it breaks.
  • I have tried with different filament (one brand new fresh from packet) - same result, I have tried drying the filament in a filament drier - same result.
  • I have replaced the nozzle
  • I have pulled the PTFE fittings from the extruder and hot end and nothing is blocked.
  • The Bowden tube is pushed fully into the hot end and extruder.
  • I have checked the extruder steps/mm and is okay.

The printer is in an enclosure and my ambient temperature is usually 30-40 °C, I'm wondering if the filament is getting heated up to the point where it is soft enough for the extruder gear to damage it?

Printing at 50 mm/s and 215 °C PLA , really lost where to go from here...

  • $\begingroup$ This is most probably a heat creep issue, resulting in a partial clog. You need to print PLA at a much lower temperature, e.g. 200 °C. Printing faster is also an option, as are less aggressive retraction settings. $\endgroup$
    – 0scar
    Nov 30 '20 at 12:51
  • $\begingroup$ Where would this clog be found? I have pulled everything off and cannot seem to find anything blocking up, i just pull some fresh filament into the extruder and it seems to print fine again for a while.. I have been printing at 210-215 since day 1 (But i was printing at faster speeds) but i will try at 200.. People keep saying to print hotter when i say the extruder is clicking.. $\endgroup$
    – bazza
    Dec 1 '20 at 0:44
  • $\begingroup$ I have now tried to print at 200C, but same issue. When it does this a can still release the spring on the extruder and push the filament through, so i don't believe it is clogging. But when i try to push the filament through from the extruder the filament seems very soft.. My extruder motor is getting very hot, i can only hold my hand on it for 1 second, i believe it is transferring this heat to the extruder gear then to the filament $\endgroup$
    – bazza
    Dec 1 '20 at 5:55
  • $\begingroup$ If your stepper is too hot you could reduce the current by adjusting the stepper driver Vref. As long as you can touch it, the stepper is OK, most operate to a temperature of about 80 °C, Unless you have PLA mountings, that shouldn't be a problem. Also heat creep softens filament causing the clog. But, if the heat is affecting the filament by altering the shape, you should at least try to lower the temperature of the stepper to rule this variable out. $\endgroup$
    – 0scar
    Dec 1 '20 at 7:10
  • $\begingroup$ Yep i have just read about the Vref so i will do that once i get a chance, I can touch it, but only for a couple of seconds, The Y-Axis motor is also very hot.. I have also ordered a heat gun so i can actually check some temperatures.. $\endgroup$
    – bazza
    Dec 1 '20 at 8:49

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