Penning this post after assembling my just arrived SnapMaker.
The issue I am having is with SnapMaker’s behaviour to a ‘Home’ command as issued through the operator panel. Snapmaker travels in the +Z (up) direction, shuffles X and Y then proceeds in the -Z (down) direction to a point where I must switch off power to avoid the printer nozzle attacking the bed.
A similar result occurs when invoking a ‘Calibration’ through the operator panel.
When in jog mode SnapMaker obeys all +/- stepping commands.
Sorry been all over the place today and about to get ready and catch a flight.
in your assemble manual (page 9 here)
What I was trying to ask you to double check is that when you assemble your snapmaker, are all the axis mounted to the correct hole as indicated ? as it sounds to be your module is physically more towards the right.
When you first hit ‘Home’ the position of the nozzle will actually move off the printing platform on the left hand side. I know it might sounds a bit dumb, but I have also done silly things when I first assemble it … !
I agree with @peteryipdesign, it sounds like you’ve not mounted one or more of the axes correctly. If not, then perhaps the limit switch of the Z-axis is not mounted or working properly. The nozzle should be off to the side of the bed and it will go below the surface in the Z direction in a normal Home command.