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Solved Extruder skipping while printing need help.

Discussion in 'Troubleshooting' started by Robert Foreman, Sep 21, 2016.

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  1. Robert Foreman

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    My extruder motor just started skipping while printing. What do I need to do to fix it? it had been doing fine till 2 days ago when I noticed small gaps in the layers. I have watched it and I can see the motor skip. Not sure how to go about fixing it.

    Thanks.
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Not sure what you mean by skipping.
    Does it stop turning or just stop extruding filament even though mechanically it seems to be working?
     
  3. Robert Foreman

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    As I watch the gears turning I see it stop and then jump forward. It does it while doing the shell but not where a retraction should happen. and it may do it 4 or 5 time per layer.
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    OK, so the motor physically stops.

    I would start by checking the stepper driver then. You can swap it for one on another axis *X or Y for example) and see if the problem moves. Not the motor, the driver card.
     
  5. Robert Foreman

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    Yes the motor stops but just for a fraction of a second. I will check the stepper drivers after the current print stops. Can I replace the current stepper driver with any other stepper driver? The reason I ask is I have 5 spare stepper drivers I ordered with a ramps 1.4 kit to redo my Da Vici 1.0 printer.
     
  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    They can be any A4988 one.
     
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  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If you have DRV8825 on the other one you don't want to swap it in.
     
  8. Robert Foreman

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    ok thanks. Start looking at it a soon as this print is done.
     
  9. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Good luck. If you tweak the firmware you can swap them all to the other style, but not really worth it
     
  10. Robert Foreman

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    Well the kit I have has the A4988 with the adjustment pot on it and as it turns out I have 5 spares for my Flash Forge Creator Pro that are A4988 without the adjustment pot. I replaced the extruder stepper driver with the A4988 with the adjustment pot and made sure the voltage was around .49 volts. That is where all the steppers were at before I pulled the one. I will post back as soon as I print a calibration box.
     
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  11. Robert Foreman

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    Well replacing the stepper driver did not work it still doing it. Here is the crazy thing. I can grab the gear on the motor and stop the motor from turning with almost no force while it's printing.
     
  12. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    See that still sounds like a weak stepper driver (tuned for too little current -- which lets the stepper motor skip steps) but it could be a failing stepper motor.
     
  13. Robert Foreman

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    The one I put in was brand new. Never been used. I have 4 more of those. Should I try to up the voltage to .6?
     
  14. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Yes, I would try a little higher output current. If that doesn't help then it is the stepper.
    The only downside to too much drive current is that the stepper will run hotter.
     
  15. Robert Foreman

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    Well I adjusted the voltage up to a .65 and it was still doing it. So I tried replacing the motor with a spare I had for my FFCP and now it's working.

    Thanks.
     
    #15 Robert Foreman, Sep 21, 2016
    Last edited: Sep 21, 2016
  16. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Cool. The motor is all that is left :) Rare for those to die, but it happens.
     
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  17. Robert Foreman

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    Thanks for the help and direction to look Mark. :)
     
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  18. Rigmarol

    Rigmarol Well-Known Member

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    I love happy endings.
     
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