E3D hotend is Jamming when printing PLA



  • Hi -

    I recently started having an issue with my Orion that has an upgraded E3D v6 hotend. Seems to start ok, and print fine for the first few layers then at some point (seems to be a random layer each time) the extruder starts skipping and the hotend is jammed. If I pause, manually extrude I can save the print (see part on the left) but if I am not nursing the 3D printer then the part fails (see part on the right).

    If it helps, when I pull the PLA out of the hotend to fix the jam - the PLA looks like it has a 'bulb' on the end (left end) - is this normal? (see second picture).

    Thanks for any help.




  • Looks like a textbook case of heat creep. PLA is prone to this. Heat travels up the filament, causing it to melt before it reaches the nozzle. The filament then gets stuck due to thermal expansion. This is the bulb you are seeing.

    Is the fan on your heat sink running continuously? Are the fins cool to the touch?



  • Yes - fins are cool to the touch and fan is always on.



  • Have you considered printing more than one of your parts in one session? The traveling between the parts and the retraction of the filament during the traveling might improve the situation.



  • Interesting idea. @TheBigWheel, what are your retraction settings? The Rostock's default Length on Move is typically too much for an E3D. I think we normally use 2.5mm.



  • Stock retract setting was 7mm changed it to 2.5mm and it seems to work much better now. Was also able to remove the E3D hotend, clean the dust that had accumulated on the cooling fins, checked to make sure the nozzle was tight against the heat break.

    All these together seemed to solve the problem. Thanks for the help,


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