Sometime when operating our cnc router, we may find that workpiece with different thickness. so when we set zero point touch On the surface of the workpiece, the workpiece thinner than last one. the tool may touch the table.

1,Move the axis to the workpiece zero point(where you have to set.) .
Like this:

Then.
Z axis move up (the distance = the depth in the program=the thickness of the workpiece ), ok, we set XYZ zero point.

Ok ,now we set workpiece here.