AON-M2 Machine Calibration
The Y and Z axes each use two endstops to home the axes. If you find that over time the axes run out of alignment, you can apply a "soft" offset to the endstops to square the axes.
Pick a point of reference and measure the distance between the reference and the physical axis on the left hand side when it is homed. Pick the same point of reference mirrored on the right hand side, and take the difference between the two values.
The offset value can be entered using
M666 [Ynnn] [Znnn] where
nnn is the offset
value in mm.
M666 for more details.