Please Help! -New CNC build- Having a glitch when reading some Gcode

Hi, Looking for some Help finding cause of a glitch i’m having. I’m currently using Fusion360 for creating Gcode but have tested others as well, (vcarve, Carbide create, etc…)
When running program it will sometimes read the G2/G3 code-line and start to hesitate, the X & Y axis will start to glitch or wiggle sideways (usually to the right side) sometimes 1/8" to 1/4".

Could anyone help direct me in troubleshooting this? possible settings or other hardware/software issues? I have gone through and changed my settings a ton of times (starting with factory- no go) trying to learn this machines setup & configuration, using guidance through a lot of recommended videos and forums, just cant seam to find correct combo. I run a plasma cnc table almost every day using Mach3 and love it,
THANK YOU in advance for any help, (Way exited to get up and running with about 1million projects combining the two metal & wood)


  • WorkBee 15ooX15oo (Bulkman3D)
  • Mach3, NVUM-V2,
  • Fusion360
  • spindle w/ VFD (just powering manually now- that’s another issue for later)
  • Nema 23 steppers
  • Dell Win7 laptop

Thanks, Bryan
(not sure if i can attach a photo?)

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1 Like

Thanks mcdanlj

That looks like lost steps, which can happen when the current is too low or when the stepper motors do not have enough power or your feed is too hiegh. Did you check the current settings on the stepper drivers?

Really frustrating to be so close and yet so far after all that!

I had a similar-looking problem with my CNC router build. However, for me the glitching happened even when not moving, and I saw it even with styrofoam, and I had good current settings. For me it was the controller board, and swapping in a new controller board without changing any stepper settings was the fix. I doubt you have the same cause. I’ve also seen a bad wiring harness have intermittent connections when moving due to vibrations present only from the machine running under load.

If all the stepper driver current settings look right, a few more things to try:

  • You can try swapping stepper drivers between axes to see whether the problem follows the motor+wiring or the stepper driver.
  • Similarly, you can try swapping wiring harness between the NVUM controller and the stepper drivers between axes and see whether the problem follows the harness.
  • If you are using 120V, double-check that the MeanWell power supply is set to 120V and not 240V power — if the switch is set on 240V and you feed it 120V, it will seem to work until you put some load on it. (The other way around, setting it to 120V and feeding it 240V, typically results in almost immediate explosive death of the power supply.)

For tests, I like to try cutting styrofoam (the cheap light kind, not the more expensive denser kind) as an initial test, though only with a vacuum running because oh the mess otherwise. In my case, it validated that I wasn’t seeing lost steps from inability to push through the material, so it wasn’t lack of power.

Hi cprezzi and thank you, I will double check current and feed, I think I have the stepper driver settings correct but will check on as well

I will check on these tomorrow, swapping is a great idea!! should eliminate a few variables. also like the styro idea ( my mysterious death plunge wont be so scary)
never thought about it.
thanks again,