I am working on aluminum metal signs with CNC laser cutting machine. I am facing some of the adjustment issues. When I send the gcode command “g92 x0 y0 z0” to reset the origin and I run my gcode program generated from “image-to-gcode” (utility included in LinuxCNC). I looked at the generated gcode and see the minimum Z depth is -7.0mm.How should it be fixed? As due to this reason I transfer my current projects to CNC cutting NYC so that my projects should be get finished on exact time. But I need to fix my own machine at time. Any suggestions?