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Extruder Stepper Not Rotating

Discussion in 'Troubleshooting' started by Connor1534654, Aug 26, 2020.

  1. Connor1534654

    Connor1534654 New Member

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    So we have been using our Robo R2 for a year or 2 now but now the extruder stepper motor seems to be malfunctioning. We wanted to confirm if there was a fix or whether we need a new stepper motor.

    So the problem started after the printer was moved location then did 2 16 hour prints. After these it then got half way to two thirds of the way through various other prints. We removed the surrounds cleaned any residue assuming it just needed cleaning. Now as you can see the motor seems to be skipping/not rotating. When light pressure applied it will start to rotate then get stuck again (not always in the same place).

    So long story short i have seen posts about stepper drivers and cleaning out contacts we have looked at but does not seem to fix the issue. So is there a fix or do we need a new stepper motor?

    Please let me know if you need anymore information!

    [​IMG]
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The R2 does not have replaceable stepper drives with the stock electronics, so if it is not a bad stepper then you will need to replace the control board (not the raspberryPi, but the larger mainboard).

    You can try to replace the stepper, partsbuilt has them in stock : https://www.partsbuilt.com/r2-parts/?sort=alphaasc&page=3
     
  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If it is the mainboard @Lance Weston has built a replacement (using standard boards like the RAMPS/Arduino) that can be bought from PartsBuilt. I am not sure what the status of that is but reach out to PartsBuilt in that case. Lance may have a better idea.
     
  4. Lance Weston

    Lance Weston Active Member

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    I had some input on the board just for the fun of it, but I do not work for Partsbuilt and have no involvement in production or sales. The board has been finalized and should be available, but I am not in that loop. I have been using the board on 3 machines with no board problems.
     
  5. Lance Weston

    Lance Weston Active Member

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    The most common problem is the cable is bad. It flexes at the hotend connector. Try carefully removing the ribbon connector at the hotend. Cut off a full inch of cable and re-crimp the removed connector. If that is unsuccessful I have a post on how to reallocate the extra stepper on the board. It is not easy but I have done it and it works. http://community.robo3d.com/index.php?threads/how-to-fix-the-dreaded-extruder-fail.23871/
     
  6. tkoco

    tkoco - -.- --- -.-. ---
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    If you find that the ribbon cable is the issue, you can try this mod by @Lance Weston
    http://community.robo3d.com/index.php?threads/extruder-stiffener-mod.24045/
     
  7. Lance Weston

    Lance Weston Active Member

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    The light pressure on the motor could easily be moving the cable and connecting/disconnecting the intermittent. It is not a good idea. If you disconnect the stepper while stepping the inductive kick will destroy the driver converting a small problem into a much larger one. The cable is cheap if bought, or fixed easily. I would do one or the other before running the printer.
     
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  8. Connor1534654

    Connor1534654 New Member

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    For all interested not a faulty stepper or issue with raspberry pi it was a faulty cable. Fixed by bypassing uptown connection via ribbon using extra long cable connected to redundant stepper connection.
     
  9. Lance Weston

    Lance Weston Active Member

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    I am terrible at finding things on the Forum so you will have to look to find how to fix the cable by cutting an inch off the hotend end, removing the connector and re-crimping it on the cable. The cable does a great deal of flexing at this joint and eventually fails. I also posted an STL for clip that you can put on the hot end to prevent that from happening in the future.

    The good thing about running a separate stepper cable is that the hotend temp regulation improves.
     

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