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Answered Extruder Stepper Motor Skipping

Discussion in 'Troubleshooting' started by coombs, Jan 19, 2017.

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  1. coombs

    coombs New Member

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    Hello all,

    My printer which has been printing beautifully for over a year now has a big problem. The stepper motor on the extruder skips and makes a terrible noise. I assume it may just be that the motor has gone bad. Should I just replace it? Where would I get a replacement? The Robo replacement parts section doesn't have one listed.

    Here's a video of it messing up:

     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    It could be the motor or the stepper driver card.

    You can check the calibration of the card:

    http://community.robo3d.com/index.php?threads/stepper-driver-calibration-information.6466/

    Personally I would confirm the motor good by swapping the motor (only as a test) electrically to the output of something else (like the X or Y axis) and then attempt to move that axis via software and see if the stepper motor turns correctly. If it does then you can be sure that the stepper driver is the source of the problem. If the problem still exists then it is the motor.

    Stepper driver boards are really cheap so hopefully that just needs to be tuned or replaced.
     
  3. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    @mark tomlinson I think he already swapped the motors from his post on the other thread.

    @coombs
    1. Thank you for starting your own thread on this.
    2. Follow the instructions @mark tomlinson has listed, paying particular attention to the two videos.
     
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  4. coombs

    coombs New Member

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    So I took a reading off the stepper driver and it read just over 5 volts. I adjusted it down to 3.8 and it still twitched. I then ran it and adjusted it to every possible voltage from 3 to 7. Same problem. Any idea what to do now:

     
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Try swapping the stepper driver card with one of the others.
    If it still twitches on the same one then it is almost certainly the stepper motor

    If the twitching moves... then it is the driver.
     
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  6. coombs

    coombs New Member

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    So I swapped the x axis driver with the extruder driver and the same problem happened. The x-axis worked fine and the extruder still skipped. Guess that means it's the stepper motor itself. Anybody know where to buy a new one? Or does Robo actually sell them?
     
  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    You need to call them. They have sold them off/on, I do not see them on the website though (which doesn't mean much)

    @Geof had luck with these: https://www.amazon.com/gp/product/B00QEXSCE8


    I also had bought some very similar (if not the same) and they were usable. Worst case is you might have to tweak some firmware settings -- like eSteps for the extruder stepper (and you should calibrate that anyway).
     
  8. Geof

    Geof Volunteer Moderator
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    Very nice steppers mark posted. Not a bad price either !
     
  9. Robert55

    Robert55 Member

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    I had the same thing happen. Went through everything your doing and it still did it. Ended up being excessive back pressure from the hot end. Seems my new cooling fan was hitting enough of the heater block to cool it off. In any event, the hot end temperature was too low for good filament flow, and it made the stepper motor skip.
     
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  10. Mark J.

    Mark J. New Member

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    This is the same problem I was having but much later in the prints, just got
    New stepper drivers and need to
    Pick up a multi tool on the way home to zero it to the proper settings. Hopefully it fixes my issue.
     
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  11. Mark J.

    Mark J. New Member

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    Was this due to putting in a new more powerful fan or was it the stock fan that caused this?
     
  12. Robert55

    Robert55 Member

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    Mark J. Neither, actually. It was a switch to the E3D V6 Volcano. Longer heater block stuck out into the air stream of the new mount for the stock fan. No insulating sock at the time. I've used ceramic tape on it for awhile now, but I'm fixing to make this: http://www.thingiverse.com/thing:2031489

    Another thing that will cause excessive back pressure is too much idler wheel pressure on the filament. The filament deforms and becomes oblong - won't fit in the feed tube to the hot end. I had this problem with PETG.
     
    #12 Robert55, Jan 20, 2017
    Last edited: Jan 20, 2017
  13. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If you swap hotend from Hex to E3D or from anything to the Volcano you must either disable the parts fan or print a new bracket for the parts fan. Like this one: http://www.thingiverse.com/thing:871733

    Or somehow manipulate the stock one to aim correctly. The stock parts fan is aimed correctly for the hexagon only.

    The "parts" fan is only for blowing on the printed part. ... not the hoend
     
  14. Robert55

    Robert55 Member

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    I noticed. Because of the slight difference in size between the Hex and E3D, I eventually cracked my X Axis and Extruder (Gorilla Glue for awhile...lol). Then I printed a different X-carriage and extruder, that takes a T-Slot part fan mount. I'm presently designing a half-round cooling fan with T mount for it. The X carriage also has a slot for the hot-end - makes changes quick, so I'm putting a hot-end together for each nozzle size. I'm also using a different idler lever with a PTFE tube from on top - I don't even have to loosen the bolts to change filament, and it handles soft filament a lot better. http://www.thingiverse.com/thing:1411833, http://www.thingiverse.com/thing:1585357
     
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