First, choose graphite as electrode material in Europe more than 90% of the electrode material is graphite. The advantages of copper, once the dominant electrode material, over graphite have all but disappeared.
Second, the reason for graphite electrode:
1, faster processing speed: under normal circumstances, the mechanical processing speed of graphite can be 2 to 5 times faster than copper; The discharge machining speed is 2~3 times faster than that of copper.
2, the material is not easy to deform: the processing of thin rib electrodes has obvious advantages; The softening point of copper is about 1000 degrees, which is easy to be deformed by heat; The sublimation temperature of graphite is 3650 degrees; The coefficient of thermal expansion is only 1/30 of copper.
3, lighter weight: the density of graphite is only 1/5 of copper, large electrodes for discharge processing, can effectively reduce the burden of machine tools (EDM); It is more suitable for the application of large molds.
4, less discharge consumption; Because the spark oil also contains C atoms, during the discharge processing, the high temperature causes the C atoms in the spark oil to be decomposed, and the protective film is formed on the surface of the graphite electrode, which compensates for the loss of the graphite electrode.
