Uneven extruder behavior

  • Hello,
    I recently finished my custom delta. My delta was printing pretty good until yesterday.
    My printer spec:
    Duet wifi 1.4 latest firmware and web interface.
    Titan extruder with 0.9 stepper (comes with titan)
    E3d V6 hotend
    other steppers are 1.8 angle 17HS4401.

    Here some pics.


    Golden benchy - i printed it yesterday, perfect print.
    Then I wanted print t-rex (same filament brand- same settings) alot of blobs-strings - disappointment 😞

    Then i decided print benchy again with same filament brand but blue, again almost perfect only one blob towards to end.

    Then yellow print - Bottom is superb but after a while started blobs and strings again.

    I did retraction test yesterday, almost perfect. today same settings same filament lot of strings..

    I sliced models with cura as relative extrusion mode enabled.

    Please help me to resolve this problem,

  • Check the set screw holding the filament drive gear onto the stepper shaft -- it could be loose.

  • First thing i re-assembled my titan after this happened. There is no mechanical problem with the extruder.

  • They are very different models so may need different settings. One possibility is that the benchy doesn't have many long print moves but the other prints may have. In which case it's possible that there is more of a pressure build up at the end of some of those longer moves. Increasing retraction might help but you could try using pressure advance (M572).

  • yes but what about yellow model, i just printed same(same filament,settings) model without problem.
    And i tested with M572 D0 S0.05 - 0.1 and off.

  • Suggest you print them all using the exact same filament. Not the same spec but different colours - the exact same filament. That will at least rule out one variable. I've had problems printing overhangs in one colour but other colours from the same manufacturer print the same part just fine. I've printed parts designed to fit together precisely - works fine with one colour but not with another.

  • Moderator

    Yes, show me a white and yellow benchy. I suspect filament as well.

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