Zaxis sinking into workspace uncontrolled

I have been controlling my mpcnc with my laptop - doing v-carves successfully. now the z-axis has started sinking into the workpiece just B4 starting the carve. could this be something mechanical or should I be looking at the control board ?? - HELP –
Thanks , Joe

Are the steppers energized before you start the router? That’ll help.


Likely possibilities:

  • Loose grub screws on the connector between the stepper and the lead screw
  • Not resetting the Z height correctly at the beginning of the carve
  • Setting the feedrate too high for the Z axis (which cannot move as fast as the X and Y axes).
  • Z axis moving by vibration from the Z stepper is energized (as Barry suggests)

Barry’s suggestion is a good one. You can test it by inserting an M17 g-code to enable your Z stepper. This should be done before the router is turned on, so if it is not already being included, and M0 will allow you to pause to turn the router on after the M17 is executed…or if you are using EstlCAM, you can send it manually before running your job.

Thanks guys for the advice – gives me something to work with. I’ll check back when I get it figured out . [ or not ] — Joe