Remember that the position of the programming zero must be specified for the numerical control system in some way. The way to specify the programming zero is very different with different CNC machine tools and CNC systems（ One of the older methods is to specify programming zeros in the program. In this way, the programmer tells the CNC system the distance from the programming zero point to the starting point of the machine tool. Usually, G92 (or G50) is used to specify at the beginning of the program, and it is likely to specify the programming zero point at the beginning of each tool.
Another new and better way to specify the programming zero point in Dongguan CNC machining plant is through the form of offset, as shown in the figure. Generally, the offset used to specify the programming zero point on the machining center is called fixture offset, and the offset used to specify the programming zero point on the turning center is called tool geometric offset.