G53 G0 Z0.

Hi.

I have only one limit switch too on all axis. On Z my switch is on an offset of -2 and home is 0. Travel is alway in minus range. Thats quite different to the US practice where 0 is on the bottom of the workpiece. I use the top of the workpiece and the bottom left edge .

Best,
Udo

flylowgofastturnleft wrote:

hello,

If I understand, Z axis need to work in negatives value ?

This is the opposite with fusion 360.

How to have a good file from Fusion ?
 

its not opposite with Fusion. Up direction is positive in fusion. If you increase the Z value you fly, if you decrease it, you sink.
Think intuitively, up is +, right is +, depth is + and their respective opposite axis are negative direction.

G53 Z0 is at the upper limit of the spindle because it is safe location and a safe number.
You can very well change that value to be something like 200 instead of 0 from the ini file. but then 0 will be on your table and when you have long endmills, entering G0 G53 Z0 means goodbye endmill. But when G53 Z0 is topmost which is the convention, it doesnt change, safe, easier to remember than 200

you'll use g54 99% of the time. You need G53 for stuff like safe z retracts, toolchanges or to park your spindle when job is finished. So these moves will not be affected by where you zero your tool and workpiece.

Btw its possibly not the reason why linuxcnc is not starting to cut.

G53 G0 Z0 is irrelevant with any postprocessor. Re-read member bevins' explanation above for a better understanding of the difference between MCS and WCS.

In short G53 is your home position, ideally. Or a machine set safe-plane, depending on the machine builder's cfg.