Pretty sure I’m having heat creep up the Bowden tube, as it’s getting jammed a few cm back from the hot end and then can’t push the filament any more. When I get it out there’s a little molten bulb at the filament.

In this fail, I think it jammed as usual and the extruder found a way to keep going.

I tried turning down the hot end from 215 to 200 and it’s still failing. My cooling fan is running at 100%.

This is the third time I’ve had this print fail at about this layer, around 1 hour into what will be a 26 hour print.

Any ideas?

  • nucleative@lemmy.worldOPEnglish
    1·
    11 months ago

    Thanks for all the comments and suggestions! I’ve cleaned the whole thing up and I changed the PrusaSlicer retraction length from 6mm to 2mm. Let’s see if this changes the result.

    This printer is mostly stock Ender 5 Plus. I upgraded to an all metal extruder (original one broke) and capricorn bowden tube a while back. Usually the defaults have been OK and I print often.

    My extruder gear leaves quite a track mark on the side of this filament and I wonder if this is contributing. I’m in a very hot and humid region and this spool is about a year old. I did have it in my filament dryer for about half a day right before this print, so it was more malleable than usual.

    Oh, and this print is a print-in-place retractable cosplay katana, so there is a ton of intricate details which seems to result in a lot more retractions and tiny movements than usual.

    • rambos@lemm.eeEnglish
      1·
      11 months ago

      Hope it works this time.

      When filament is jammed at any place in its path this can happen. It seems like extruder is working fine and leaving teeth marks on the filament is normal.

      It could be that 6mm retraction length can work, but it jams on job that requires too many retractions. Its best to do a retraction test and pick the lowest possible distance that leaves no stringing or just live with accaptable amount. 6 mm distance is more suitable for longer bowden tubes, I guess you should be between 1-4 mm.

      There is also a slicer setting that limits number of retractions per length of filament. Then slicer ignores some retractions to protect the print job from failing (usually extruder grinding)

      • nucleative@lemmy.worldOPEnglish
        1·
        11 months ago

        Thanks for these useful suggestions. I’m learning all about how retractions work now and surprised I never ran into issues like this before.

        We are about 4.5 hours into another attempt (previous all failed around 1hr), now with the updated retraction length. It’s still going strong. Seems like this is the solution!