1，Electrical discharge machining
Electrospark machining is a special machining method that uses the electro-erosion effect generated by pulse discharge between two electrodes immersed in a working fluid to remove conductive materials. It is also called discharge machining or electro-erosion machining.
EDM is suitable for machining of complex parts such as precision small cavities, narrow slits, grooves, corners, etc. When it is difficult for the tool to reach the complex surface, where deep cutting is required, and where the aspect ratio is particularly high, EDM is better than milling. For the machining of high-tech parts, milling electrode re-discharge can improve the success rate. Compared with the high and expensive tool costs, EDM is more suitable. In addition, where EDM finishing is required, EDM is used to provide a spark pattern surface. With the rapid development of high-speed milling today, the development space of EDM has been squeezed to a certain extent. At the same time, high-speed milling has also brought greater technological progress to EDM. For example, the use of high-speed milling to manufacture electrodes greatly reduces the number of electrode designs due to the realization of narrow area processing and high-quality surface results. In addition, the use of high-speed milling to manufacture electrodes can also improve production efficiency to a new level and ensure the high precision of electrodes, which also improves the precision of EDM.
2，Basic equipment: EDM machine.
3，Main features
It can process materials and complex-shaped workpieces that are difficult to cut by ordinary cutting methods; there is no cutting force during processing; no defects such as burrs and cutter marks and grooves are generated; the tool electrode material does not need to be harder than the workpiece material; it is directly processed using electric energy, which is easy to realize automation; a metamorphic layer is generated on the surface after processing, which must be further removed in some applications; the purification of the working fluid and the treatment of smoke pollution generated during processing are relatively troublesome.
EDM has the following characteristics
It can process any high-strength, high-hardness, high-toughness, high-brittleness and high-purity conductive materials; there is no obvious mechanical force during processing, and it is suitable for processing low-rigidity workpieces and fine structures: the pulse parameters can be adjusted as needed, and rough processing, semi-finishing and finishing can be performed on the same machine tool; the pits on the surface after EDM processing are conducive to oil storage and noise reduction; the production efficiency is lower than that of cutting processing; part of the energy is consumed on the tool electrode during the discharge process, resulting in electrode loss and affecting the forming accuracy.
4，Scope of use
Processing molds and parts with complex-shaped holes and cavities; processing various hard and brittle materials such as cemented carbide and hardened steel; processing deep and fine holes, special-shaped holes, deep grooves, narrow slits and cutting thin sheets; processing various forming tools, templates and thread ring gauges and other tools and measuring tools.
Three conditions must be met for EDM
- A pulse power supply must be used
- An automatic feed adjustment device must be used to maintain a small discharge gap between the tool electrode and the workpiece electrode
- Spark discharge must be carried out in a liquid medium with a certain insulation strength (10~107Ω·m).
Not all mold steels can be processed by mirror EDM
Some mold steels can easily achieve a mirror effect by EDM, while some mold steels cannot achieve a mirror effect no matter what. At the same time, the higher the hardness of the mold steel, the better the mirror effect of EDM.
