Different from the traditional cutting method, EDM is a machining method that uses the electrical corrosion phenomenon generated by the pulse discharge between the tool electrode and the two poles of the workpiece to process the size of the workpiece. One of the simplest examples of galvanic corrosion phenomena is galvanic corrosion of the contacts of electrical switches, which is caused by sparks generated when the contacts are opened and closed, gradually damaging the contacts.

The main reason for spark corrosion is that a high-temperature heat source is instantaneously generated in the spark channel when the spark is discharged, which melts and vaporizes the local metal and corrodes it.

But this simple electro-erosion does not yet constitute a practical EDM. Practical EDM requirements:

1. A certain gap must be maintained between the electrode of the tool and the machined surface of the workpiece, usually about a few microns to several hundreds of microns. If the gap is too large, the inter-electrode voltage cannot break down the inter-electrode medium, so spark discharges cannot be generated. If the gap is too small, it is easy to form a short-circuit contact, and no spark discharge can be generated. Therefore, there must be an automatic gap adjustment device in EDM, which is called a servo control system.

2. The spark discharge should be a short-term pulse discharge, the discharge duration is 10s, and it needs to stop for a period of time after each discharge to ensure deionization and avoid continuous arc discharge to burn the workpiece.

3. Spark discharge must be carried out in a liquid medium with certain insulating properties, such as kerosene, saponification liquid, etc. Liquid media, also known as working fluids, must have:

(1) It has high insulating properties to facilitate the generation of pulsed spark discharges

(2) The liquid medium should also exclude the galvanic corrosion products in the gap to ensure that the repetitive pulse discharge dispersed in time and space can be carried out normally.

(3) The role of cooling electrodes.

Therefore, general EDM equipment has devices to achieve these requirements, which include pulse power supply, working fluid circulation system, relative servo feeding system between tool electrode and workpiece, and machine tool main body.

It is mainly used to process various complex and precise small workpieces, such as punches and dies of molds. It is developed on the basis of EDM perforation and forming. It has not only developed the application of EDM, but also replaced EDM perforation and forming in some aspects. Wire cutting machine tools have accounted for more than half of EDM machines.

CNC EDM Factory

Shanghai Languang Precision Machinery Co., Ltd. is a company specializing in precision machining and manufacturing of parts. At present, the machining products involved are mainly processed by CNC numerical control machine tools. We have advanced processing technology, if you have related needs, you can visit our company's website to contact us.