Odd behavior from Motor. Please help!


I am having a strange issue. As I am cutting cabinet ribs out of a sheet when it gets to the 2-4th pass (.5mm increments) It starts to bounce up and down. The x/y motor on the left side moves back and forth (See video link at the bottom of post), while the x/y motor on the right continues to operate normally. It continues this motion around in a circle following the tool path it should be on. It also continues to do this jerking motion after being paused/reset in Makerverse and will not stop until I unplug the motors. It appears to always start in the same general region of the sheet (top middle-ish). I have successfully cut many other sheets along this same plain without ever having this issue. I have an XL frame.

All of the rest of the cuts I have been making have turned out great, including rabbits and dedos and I had the machine pretty well calibrated to 1mm. It cuts great until it gets to this particular point and goes haywire. Again I have cut many other sheets right at this same point.

I am using Cam Bam with GRBL post processing and despite some other challenges I have worked through, it has successfully cut many sheets. My only conclusion can be a bad motor. There were some other red flags in the kit that made me think maybe it had been returned. The Z axis bracket was bent and some of the parts looked used.

I have tried:
-Changing the bit
-Altering all parameters in Cam Bam
-Slowing Depth increment speed dramatically


Could the controller be overheating? That seems quite dramatic, but I have seen the controller overheat and cause movements a little bit like that.

Your fist instincts for what to do were spot on, that’s what I would have recommended.

Does it work after letting it cool off. If so keep a fan on it. I had mine overheat before and do some weird stuff.

If not, I would try the following.

  1. Reset all cables at both ends. Might fix it.
  2. Swap cables at both ends, if it follows bad cable.
  3. Swap motors, if it follows bad motor.
    If not bad board?
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