When CNC machine tools work, do not need workers to operate the machine tool, but to automatically implement people's intentions, this must establish a certain relationship between people and CNC machine tools, the media of this relationship is called control medium (or program medium, input medium, information carrier).

CNC machine tool worktable by processing process classification：

1. The corresponding CNC machine tools for metal cutting and traditional turning, milling, drilling, grinding and gear machining are CNC lathe, CNC milling machine, CNC drilling machine, CNC grinder, CNC gear machining machine tools, etc.Although these numerical control machine tools in the processing process methods are very different, the specific control method is also different, but the movement and movement of the machine tools are digital control, with a high degree of productivity and automation.In the ordinary CNC machine tool to add a tool library and tool changing device to become the CNC machining center machine tool.The machining center machine tool has further improved the automation degree and the production efficiency of the common numerical control machine tool.Milling, boring, boring machining center, for example, it is based on CNC milling machine increased the capacity of a large knife library and automatic tool change device, a clamping workpiece, all five surface even most of the body parts machining process for milling, boring, drilling, expanding, reaming and tapping screw thread machining, particularly suitable for casing parts processing.Machining center machine tool can effectively avoid the positioning error caused by the workpiece installation for many times, reduce the number of machine tools and floor space, shorten the auxiliary time, greatly improve the production efficiency and processing quality.

2, special processing type CNC machine tools in addition to cutting machining CNC machine tools, CNC technology is also widely used in CNC edm wire cutting machine tools, CNC edm forming machine tools, CNC plasma arc cutting machine tools, CNC flame cutting machine tools and CNC laser processing machine tools.

3, plate processing type of CNC common application in the metal plate processing of CNC machine tools have CNC press, CNC shearing machine and CNC bending machine.In recent years, numerical control technology has been widely used in other mechanical equipment, such as CNC multi-coordinate measuring machine, automatic plotter and industrial robot.

The commonly used control medium is the standard perforated tape of 8 units, and the commonly used perforated tape is made of paper, so it is also called paper tape.The width is 25.4mm and the thickness is 0.108mm, and each row can have up to 8 information holes of 41.33mm in addition to a synchronization hole of 41.17mm.Different codes are represented by the arrangement and combination of 8 holes in each line (the arrangement of holes on paper tape is called the code).The punch tape is input to the tape reader of the nc device, and then the tape reader converts the code of the punch tape into the electrical signal that can be recognized and processed by the nc device, and transmitted to the nc device, thus completing the input of the command information.