Keep in mind that in Mach there are "machine coordinates" and "work coordinates". The machine homes to the machine coordinates, these are absolute positions on your table that should represent the full working envelope of the machine. Then, you have work coordinates, these are where you can type in a position. Say that in machine coordinates that Mach indicates that you machine is at X 24.000 Y 24.000. If you have a 4'X4" machine, this is in the middle of the table. But, you can type into the "work" coordinates a value of X 0.000 and Y 0.000, now you can run a job from that location and your G code will drive the machine based on this position and NOT the machine coordinates. You can place material anywhere on your table and set your work coordinates to work from there, however, keep in mind not to start a job in a place on your table where your G code will attempt to exceed the working envelope of your machine. If you have soft limits enabled, Mach will warn you of this.
Scott |