In the late 1940s, the United States began to study CNC machine tools. In 1952, the Massachusetts Institute of Technology (MIT) Servo Mechanism Laboratory successfully developed the first CNC milling machine, which was put into use in 1957. This is a major breakthrough in the development of manufacturing technology, marking the beginning of the era of CNC machining in the manufacturing field. CNC machining is the foundation of modern manufacturing technology, and this invention has epoch-making significance and far-reaching impact on the manufacturing industry. The major industrial developed countries in the world attach great importance to the research and development of CNC machining technology. my country began to develop CNC machine tools in 1958, and successfully trial-produced CNC machine tools equipped with sub-tube CNC systems. In 1965, it began mass production of three-coordinate CNC milling machines equipped with transistor CNC systems. After decades of development, the current CNC machine tools have achieved computer control and are widely used in the industry, especially in the mold manufacturing industry.
For the needs of metal cutting processes such as turning, milling, grinding, drilling and planing, as well as special processing technologies such as electrical machining and laser processing, various types of CNC machining machines have been developed.
CNC machining machines commonly used in mold manufacturing include: CNC milling machines, CNC EDM machine tools, CNC EDM wire cutting machine tools, CNC grinders and CNC lathes.
CNC machine tools are usually composed of control system, servo system, detection system, mechanical transmission system and other auxiliary systems.
The control system is used for the operation, management and control of CNC machine tools. It obtains data through the input medium, interprets and operates on these data and acts on the machine tool; the servo system drives the machine tool according to the instructions of the control system, so that the tools and parts execute the CNC code regulations. The detection system is used to detect the displacement and speed change of the machine tool executive parts (table, turntable, slide plate, etc.), and feedback the detection results to the input end, compare with the input command, and adjust the machine tool movement according to the difference. ;The machine tool transmission system is a mechanical feed transmission device between the feed servo drive element and the machine tool execution part; there are many kinds of auxiliary systems, such as: fixed cycle (can perform various repeated processing), automatic tool change (exchangeable Specify the tool), drive backlash compensation to compensate for the backlash error generated by the mechanical drive system) and so on.
In CNC machining, CNC milling is the most complex and has the most problems to be solved. In addition to CNC milling, the CNC programming of CNC wire cutting, CNC EDM, CNC turning, CNC grinding, etc. has its own characteristics. This book will focus on the CNC milling process that has guiding significance for CNC machining programming. programming.