There are many kinds of graphite products, such as ordinary graphite, impregnated graphite, fine graphite, high purity graphite, isostatic graphite, and a very special kind of graphite, that is, electric spark, graphite, or EDM graphite!
EDM graphite is mainly used in the production of dies. It has excellent properties that copper metal can not match. The electric spark graphite itself has the characteristics of non-metallic material, and it also has some characteristics of metal. Electric spark graphite density is smaller than copper, light quality, can bring many benefits to production; easy processing; from hardness, electric spark graphite is 1/3 of copper metal; and conductivity is less than metal copper;
The high temperature resistance of electric spark graphite is better than that of copper metal. The melting point of copper is more than 1300 degrees, while the melting point of electric spark graphite is about 3800 degrees. High melting point can be greatly reduced, after the electronic pulse produced by a large number of high temperature, so that melting itself, causing sublimation phenomenon. In addition, the electric spark graphite processing is simple, and the production speed is fast, and the production capacity is not to be worried!
EDM is a new processing technology in machinery manufacturing industry, EDM of many high hardness metal processing, and processing of complex shape, high precision parts, can be used as a tool for the anode copper material, also can use graphite materials. As a tool for EDM, the graphite material of electrode must have the following conditions:
(1) the structure is compact and the tissue is homogeneous; there should be no coarse particles and large pores;
(2) with high mechanical strength and good processability, it can work out complex shapes or sharp angles and flakes;
(3) the graphite tool electrode has a certain loss in the process of EDM, and this loss should be as low as possible;
(4) the discharge characteristics are stable and the processing speed is faster. Therefore, graphite with fine grain structure or graphite with fine particle structure is generally used in EDM, and the physical properties of graphite are best isotropic. Therefore, the graphite material with fine grain structure is the most popular graphite material used in China's electrical discharge machining.
In 2005, the domestic needs of EDM graphite is estimated to be 4000T, of which about 25% of high-grade graphite is used, and about 75% of middle and low-grade graphite is used. It is likely to rise by an annual increase of 10%. The use of imported high-grade graphite (mainly isostatic molding of isotropic graphite), accounting for about 10% of the total amount. There are many kinds of isotropic graphite for EDM abroad. They can be used in rough, semi finish, finish machining, fine machining, super fine machining and precision machining (line cutting, etc.).