Archive for September, 2016

Development history of CNC machine tools

In the mid-20th century, with the development of electronic technology, automatic information processing, data processing and the emergence of electronic computers, to the automation technology has brought new concepts, with digital signals on the machine tool movement and control of processing, and promote the automation of machine tools development of.
Machining with digital technology was first implemented in the early 1940s by a small aircraft industry contractor, Parsons Corporation, in North Michigan, United States. They used the all-digital computer to process the data of the machining path of the wing in the frame of the aircraft and the rotating wing of the helicopter, and the influence of the diameter of the tool on the machining route was taken into account, making the machining accuracy ± 0.0381mm 0.0015in), reached the highest level at that time.
In 1952, Massachusetts Institute of Technology in a vertical milling machine, fitted with a set of experimental numerical control system, successfully achieved simultaneous control of three-axis movement. This CNC machine tool is known as the world’s first CNC machine tools.
The machine was an experimental machine, and in November 1954, the first industrial CNC machine was officially produced by Bendix-Cooperation in the United States on the basis of Paterson’s patent.
Since then, since 1960, some other industrial countries, such as Germany, Japan have been developing, producing and using CNC machine tools.
CNC machine tools and the first appeared in the use of CNC milling machine, because CNC machine tools can solve the ordinary machine tool is difficult to perform, the need for contour processing curve or surface parts.
However, due to the use of the numerical control system is a tube, bulky, high power consumption, so in addition to military use, in other industries have not been promoted.
By 1960, point control of CNC machine tools have been rapid development. Because the position control numerical control system compared to contour control numerical control system to be much simpler. Therefore, CNC milling machines, presses, coordinate boring machine a lot of development, according to statistical data show that by 1966 the actual use of about 6,000 CNC machine tools, 85% of the point of control of the machine.
The development of CNC machine tools, it is worth mentioning that the processing center. This is a kind of automatic tool changer with CNC machine tools, it can achieve the workpiece at a time to install the card for multi-process processing. This product was originally developed in March 1959 by Keaney & Trecker Corp., USA. This machine tool is equipped with taps, drill, reamer, cutter and other tools in the tool magazine, according to the instructions of the perforated belt automatically select the tool, and through the robot tool mounted on the spindle, the workpiece processing. It can shorten the loading and unloading time on the machine parts and replace the tool time. Machining centers have now become a very important product in CNC machine tools, not only vertical and horizontal machining centers for boring and milling of box parts, but also turning centers for grinding whole parts, grinding centers Wait.
In 1967, the United Kingdom first of several CNC machine tools connected to a flexible processing system, which is the so-called flexible manufacturing system (FlexibleManufacturingSystem – FMS), the United States, Europe, Japan, have also been developed and applied. After 1974, with the rapid development of microelectronics technology, microprocessors directly used in CNC machine tools, numerical control software to enhance the function, the development of computer numerical control machine tools (referred to as CNC machine tools), to further promote the universal application of CNC machine tools And vigorously develop.

In the 1980s, a flexible manufacturing unit (FlexibleManufacturingCell – FMC) with 1 ~ 4 machining center or turning center as the main body, and equipped with automatic loading and unloading of workpiece and monitoring and checking device appeared in the world. This unit of investment is less effective, can be a single long time to care for the operation of small, can also be integrated into the FMS or more advanced integrated manufacturing system to use.
At present, FMS from the cutting to the plate cold work, welding, assembly and other areas of expansion, from small batch processing to high-volume processing development.
So the machine tool CNC technology, is considered the basis of modern mechanical automation technology.

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