G28 G91 Z0.0 M05

Remember:  G28 uses G91 to find machine home. G28 changes the coordinate system to the machine coordinate system. This sets the axes to (0, 0, 0) in the default coordinate system of the machine. G91 then finds the coordinates in the machine coordinate system. Z0 directs the machine to that position, which is commonly the tool change position.

There’s one more step.  The spindle must be turned off.  It’s a safety thing. We do not want unnecessary rotating cutters.

M05 is Spindle Stop.

The footer occurs at the end of a cutting operation.

When the part requires another cutting tool to make a different type of cut, a code in the footer can pause the program while the tool changes.  It is a called a conditional stop or optional program stop. It does not end the program.  It is just a pause.  The code is M01.

There are other reasons why an operator might use an M01 code. Right now, we want to focus on the footer which ends a specific cutting operation.

When the footer is at the end a part’s program, then we want to end the program.  That code is M30.  It is usual for this code to be the very last code in a CNC program.  It usually means the part is finished, too.