Hi, One of the big things that Gerry has managed to solve with the semi-auto toolchange is that Z datums aren't always made on the top surface of a workpiece. Quite often the Z datum is the bottom of the work, especially if the whole of the top surface is machined in the first operation. In this case, if your Z datum was the top surface, your datum has now disappeared.
I often machine 3D foam shapes where one side is machined first then the other side is machined by sitting the first side in a cradle. For this operation, my Z datum is the surface of the cradle and does not reference the actual workpiece at all.
Something else worth mentioning is that Gerry has made it possible to use the semi-auto toolchange function with or without spindle control from Mach. With spindle control, the toolchange routine is seamless. Without spindle control, the routine prompts for the spindle to be started.
This is one excellent screen set. (In a very British accent) You are definitely the man, Gerry
Mike