I built my CNC a couple years ago. Lately, I've noticed that if I run code that has heavy Z axis movement, it slowly lowers itself throughout the cut. In other words, if I set home to 3.5" above the table surface and run 75k lines of heavy Z movement, and send it back to home, the machine will be about 3" above the table surface.

I tested decreasing and increasing the Z axis speed/acceleration. It had no impact on this variance. I did the tests without the router on, so it was just the CNC moving to help reduce any influences on the machine.

It hit me today, that I upgraded my Z axis about a year ago.I'm beginning to think the Z axis isn't getting enough power to move the new and significantly heavier Z axis under increased use.

It's been a while since I've looked at the electrical on my machine. This CNC build is also the most advanced electrical work I've ever done, so I just want to make sure I'm thinking through my changes correctly before making a change.


  • I was going to slightly increase the voltage on the backside of the G540 for the Z axis. Looking at diagrams, I believe there is a small screw that you can adjust to increase/decrease voltage
  • Is there a way for me to measure the voltage while I adjust? If so, how?
  • Is there a target voltage setting I should be aiming for?


Appreciate the help!