I encountered an incomprehensible situation and after repeated testing, I was unable to identify the problem

As the title suggests, I assembled a DIY laser engraving machine and purchased a large number of brand new accessories.
There is no problem with the power supply, and the motor should also be fine, as it has undergone precision testing by Lasergrbl (with a testing distance of 18cm and a motor speed of 8000mm/min). Prove that the XY repeatability accuracy of the machine is very high, and there is no problem with the machine structure.
It shouldn’t be a problem with the motherboard either, because I have replaced several motherboards in a row and they all have the same problem. Even if one of them has a problem, it is almost impossible for all of them to have problems in a row, so I don’t think it’s a problem with the motherboard.
The suspect came to the laser, but I replaced three lasers and the problem also occurred, so I don’t think it’s a laser problem.
I don’t think it’s a problem with the transmission system either, because when the motor is locked and the pulley of XY is pushed by hand, there is no sliding, and the previous repeated accuracy and precision tests are sufficient to prove that it’s not a problem with the machine structure.
It’s not a problem with the data cables or power supply. When using them before, the situation was very stable, and any problems with the power and data cables would directly cause the machine to disconnect rather than become crooked or twisted. But I didn’t disconnect.
Moreover, I even tried uninstalling and reinstalling the software and replacing the motherboard, but the problem still persists.
I am very confused and don’t know where the problem lies. Please advise me

It would appear to me as a grub screw that’s slowly coming loose.

I think you have the issue, even with the no problem photo. In fact I think it’s worse.


The photo of the lines doesn’t mean much to us, I’m sure you know how it was oriented in the machine when you did it, but we’re clueless.

There must be something loose or loosening up… I’d look at the grub screws.

Good luck


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