In the middle of the 20th century, when the Soviet Lazarinkov women studied the phenomenon and causes of corrosion damage to switch contacts by spark discharge, they found that the instantaneous high temperature of electric spark could make the local metal melt and oxidize and be corroded away, thus creating and inventing the electric spark machining method wire-cut discharge machine was also invented in the Soviet Union in 1960. At that time, a projector was used to view the contour before the left and right manual feed to the table for processing, and it was thought that the processing speed was slow, but it could process the fine shapes that were not easily processed by conventional machinery. A typical practical example is the processing of shaped holes by chemical weaving nozzles. The processing fluid used at that time was mineral oil (lamp oil). Because of the high insulation and small distance between poles, the processing speed was lower than that of the current machine, and the practicality was limited.
The first machine to be NC-educated and processed in deionized water (close to distilled water) was exhibited at the 1969 Paris Workhorse Exhibition by a Swiss electrical discharge machine manufacturer, which improved the processing speed and established the safety of unmanned operation. However, the production of NC paper tape was very laborious, and it was a great burden to the user if it was not programmed automatically by a large computer. Until the advent of inexpensive Automatic Programed Tools (APT), the popularity was slow.
The Japanese manufacturer developed a small computerized automatic programmed wire-cutting EDM machine, which is cheap and accelerated the popularity. The processing shape of WEDM is a quadratic profile. The emergence of the simple APT (APT language is easier than the official model) was an important factor in the development of WEDM machines.