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Partial Answer Filament stops extruding early in print but extrudes manually just fine.

Discussion in 'Troubleshooting' started by dbvanhorn, Jul 29, 2016.

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  1. dbvanhorn

    dbvanhorn Active Member

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    I just installed a new hexagon, and I thought all was fine, but I can't actually print.

    It's very confusing. There's no jam at the nozzle. I can install filament and push it down manually and I get a rather surprising amount of filament out of a 0.4mm nozzle in a very short time. Free flowing, looks great.

    So I load it up and clamp the filament in the extruder, and spin the wheel of karmic extrusion, and I get a nice bit of filament, all looks normal.

    I go in through MC, and command extrusion of 10mm or 100mm, seems totally normal.

    I start a print, and immediately (!) I'm dramatically underextruding, and the hobbed bolt is chewing the filament.

    Open the extruder, remove filament, discard chewed end, lather rinse and repeat.

    Extrusion temp with this is normally 192C and I've tried 185 to 210 experimentally with no difference.
    The printhead is flying just above the glass as normal, not jamming due to scrubbing the glass with the head.

    Obviously the new hexagon is a possible problem, but where is it going wrong? It seems like the problem happens at the heat break, but if I can manually push the filament at 2x to 3x normal extrusion rate, why would I have a problem printing?
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Is it too close to the bed? What is your Z offset?
     
  3. dbvanhorn

    dbvanhorn Active Member

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    0.55mm works for me, I can see a gap between the head and the glass.

    I thought it might be the hobbed bolt, but that's all cleaned out and it's still having the problem.
    Once it jams, I can't push it by hand either. Before the jam, I can push it through manually very easy.
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    PLA or something else?

    If it is PLA then season the nozzle or add an oiler
     
  5. dbvanhorn

    dbvanhorn Active Member

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    PLA. A roll I've used before without issues.
     
  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  7. dbvanhorn

    dbvanhorn Active Member

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    Seasoned.

    It's a type of jam that I've not seen before, and what seems weirdest to me is that I can extrude by hand all I like and it's fine. The moment I start a real print, on the perimeter ring, it's jammed. Rate specific?
     
  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Yes, the type of clogs that PLA creates are temporary/intermittent and often not complete blockages either rather it is trying to stick to the inside of the extruder and nozzle as it flows through.

    The seasoning makes sure it will not stick. Add a poor mans oiler and see if affects it ... Tape a section of paper towel around the filament where it goes into the extruder and make sure it has some oil on the paper (not drenched, just a wet patch) where the filament can rub against it as it passes through. Just tape that in place and try a print. If that helps you can print a real oiler.
     
  9. dbvanhorn

    dbvanhorn Active Member

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    Re-did the seasoning, and installed new nozzle JIC.
    Still jamming. I finished an hour long print, and it jammed at the start of the next.
    Same thing, manual feed is fine, but the moment I start printing I get a dribble.

    If I extrude 10mm almost nothing comes out while the gears are turning, but it comes out very slowly for about 30 seconds.

    If I pull the filament and re-start, I can hand feed or motor feed as much as I like till I start actually printing.

    I don't even know how it "knows" when to jam!
     
  10. dbvanhorn

    dbvanhorn Active Member

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    Wrestled with it some more last night, got a few good prints, then having the same issue this morning.

    So I changed filament, to a roll I've used a lot. Same problem.

    Oiler and seasoning isn't it. The extruder is making all the right motions, but the output strongly suggests a clog.
    I can't find any clog.
    Removing and reinserting the filament clears the problem up for a little while, minutes to hours if I get lucky.

    What else can I change or check to resolve this?
     
    #10 dbvanhorn, Jul 30, 2016
    Last edited: Jul 30, 2016
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I assume the hobbed bolt is clean and the tension on the feed screws tight?

    You might want to try a new nozzle. The only reasons extrusion will suffer is a clog or other blockage, mechanical issues feeding the filament into the extruder or the extruder motor.

    You *might* want to adjust the stepper motor driver (or replace it) for the extruder since if it were detuned or failing it would cause the extruder to miss steps and that would certainly act a lot like a clog.
     
  12. Bruce Fyfe

    Bruce Fyfe New Member

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    I am having the exact same problem. I have tried new filament, new print head. Anybody have any more input?
     
  13. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Try every thing suggested in this thread including the linked video.
     
    Geof likes this.
  14. Geof

    Geof Volunteer Moderator
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    @Bruce Fyfe if you still need help start up a new thread and we will get you there
     
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