In the middle of the 20th century, when the Soviet Union Lazarinko couple studied the phenomena and causes of the corrosion damage of switch contacts by spark discharge, they found that the instantaneous high temperature of the electric spark could melt, oxidize and corrode the local metal, thus creating and inventing the electric discharge machining method. The wire-cut discharge motor was also invented in the Soviet Union in 1960. At that time, the projector was used to look at the front of the outline and the left and right hand feed the working table processing, in fact, it was believed that although the processing speed was slow, it could process the micro shape that the traditional machinery was not easy to process. The representative practical example is the processing of profile-shaped holes of chemical jet nozzle. Mineral material oil (lamp oil) for processing fluid used at that time. High insulation, small distance between electrodes, processing speed is lower than the current machine, limited practicality.
The CNC, in deionized water (close to distilled water) processing machine type first by the Swiss discharge processing machine factory in 1969 Paris working machine exhibition, improve the processing speed, establish the safety of unmanned operation. But the NC paper tape is very laborious, if do not use large computer automatic program design, is a great burden to the user. Its popularity was slow until the advent of inexpensive Automatic Programed Tools APT.
Japanese manufacturer developed with minicomputer automatic programming wire cutting discharge machine cheap, accelerated popularity. The machining shape of wire-cut discharge machining is quadratic contour. APT(APT language is easier than formal models) is widely used in automatic programming devices. The appearance of APT in simple form is an important factor in the development of wire-cut amplifier.