Brief introduction to the development of CNC techn

2022-08-22
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A brief introduction to the development of machine tool numerical control technology

in the mid-20th century, with the development of electronic technology, the emergence of automatic information processing, data processing and electronic computers has brought new concepts to automation technology. Using digital signals to control machine tool motion and its processing process has promoted the development of machine tool automation

machining with digital technology was first realized by Parsons Corporation, a small aircraft industrial contractor in North Michigan in the early 1940s. When manufacturing the frame of the aircraft and the rotating wing of the helicopter, they used the full digital electronic computer to process the data of the wing processing path, and took into account the influence of the tool diameter on the processing path, so that the processing accuracy reached ± 0.0381mm (± 0.0015in), reaching the highest level at that time

In 1952, MIT installed an experimental numerical control system on a vertical milling machine and successfully controlled the movement of three axes at the same time. This CNC machine tool is known as the first CNC machine tool in the world

this machine tool is an experimental machine tool. By November, 1954, based on the patent of Parsons, the first Industrial CNC machine tool was officially produced by Bendix Cooper company (Bendix Cooper fixture base 9 is connected with the positioning hole on the bench 12 of the experimental machine through the positioning pin 11)

since then, since 1960, some other industrial countries, such as Germany and Japan, have successively developed, produced and used CNC machine tools

CNC milling machines were first used in CNC machine tools, because CNC machine tools can solve curve or surface parts that are difficult for ordinary machine tools and need contour machining

however, because the numerical control system at that time used electronic tubes, which were huge in size and high in power consumption, the instrument was not reliable and widely used in other industries except in military departments

after 1960, CNC machine tools with point control have developed rapidly. Because the point control CNC system is much simpler than the contour control CNC system. Therefore, CNC milling machines, punches and coordinate boring machines have developed greatly. According to statistical data, 85% of the 6000 CNC machine tools actually used by 1966 were point control machine tools

In the development of CNC machine tools, machining centers are worth mentioning. This is a kind of CNC machine tool with automatic tool changing device, including center line perpendicularity measurement and side line perpendicularity measurement. It can realize the workpiece loading and multi process processing at one time. This product was first manufactured by Keaney treckercorp. in March 1959 Developed. This machine tool is equipped with taps, drills, reamers, milling cutters and other tools in the tool magazine. The tools are automatically selected according to the instructions of the perforated belt, and the tools are installed on the spindle through the manipulator to process the workpiece. It can shorten the loading and unloading time of parts on the machine tool and the time of tool replacement. Machining centers have now become a very important variety of CNC machine tools. There are not only vertical and horizontal boring and milling machining centers for box parts processing, but also turning centers and grinding centers for rotating integral parts processing

in 1967, Britain first connected several CNC machine tools into a flexible processing system, which is the so-called flexible manufacturing system (FMS). After that, the United States, Europe, Japan and other countries also developed and applied it one after another

after 1974, with the rapid development of microelectronics technology, microprocessors were directly used in NC machine tools, which strengthened the software functions of NC and developed into computer numerical control machine tools (referred to as CNC machine tools for short), further promoting the popularization, application and vigorous development of NC machine tools

in the 1980s, flexible manufacturing cells (FMC) with 1 ~ 4 machining centers or turning centers as the main body and equipped with automatic workpiece loading and unloading and monitoring and inspection devices appeared in the world. This kind of unit has less investment and quick effect. It can not only be operated by few people for a long time alone, but also be used in FMS or higher-level integrated manufacturing system through the alliance's special research and development funds and project management measures, intellectual property management measures, scientific research project evaluation system, performance evaluation system and financial management system adopted at this meeting

at present, FMS has also expanded from cutting processing to plate cold work, welding, assembly and other fields, and from small and medium-sized batch processing to large-scale processing

Machine tool numerical control technology is considered as the basic technology of modern mechanical automation

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