Weird motor movement on the X

  • Hi all,

    Running a Hypercube Evolution (CoreXY) powered by a Duet WiFi and noticed that I've got some random movements in my X axis. It's not all the time, just maybe 1 in every 10 movements. Easiest way to describe is by YouTube hosted video:
    Just moving the X in 10mm increments.

    Doesn't happen on the Y, just the X.

    I doubt it's something to do with the hardware or firmware. Could one of my motors be dying?


  • administrators

    I'm not an expert on CoreXY machines, but my guess is that one of the belts is loose, or one of the pulleys is loose, or one of the motors is skipping steps.

  • I agree with David. For pure X positive moves on a CoreXY, both motors are employed, running in different the same direction and at the same speed (edit Y uses both motors but running in different directions) . Whilst with a single motor, the moves will be at 45 degrees. So if one belt doesn't travel the same distance as the other for whatever reason, it will lead to an angular movement (i.e. some movement in Y as well as X) which is what the video shows is happening. My best guess would be a loose pulley, or at least, that's what I would check first.

  • sigh I can't believe it, but it seems a grub screw had fallen out of one of the motor pulleys. I can't believe I asked a question on a forum before checking that.

    Sorry guys. Appreciate the help.

  • No worries. Glad you got it fixed. (and we've all done it so feel bad about it).

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