Hi,

it is common practice to have the top of the Z travel to have machine coordinate of z=0. Therefore any Z axis move has machine coordinates of less than zero, ie negative.

A lot of new users baulk at such a thing. Under normal circumstances you have the machine set to display work coordinates. Thus the top of your material would be z=0,

above and free of the material positive z and bleow the surface, ie cut depth is negative z. But these are WORK coordinates, they are easy to understand and visualize.

MACHINE coordinates are a little different and especially so when all normal working z machine coordinates are negative.

With the Z axis at the very top of travel machine coordinate z=0. If you jog downwards 105mm say, to the top of your workpiece the machine coordinate would be z=-105.

If you were doing a 1mm cut the machine coordinate would be z=-106mm. It may look a little strange at first but it will make sense in the end. Mach tracks and operates

in machine coordinates its only us humans who need help with conveniences like work coordinates. Negative z machine coordinates are just fine for Mach and once you and

I get used to seeing negative z machine coordinates we too can derive good understanding of our machine.

Craig