Graphite electrode materials can be classified into different grades according to their particle size. Of course, for the user, the choice of graphite electrode material is very critical, because it directly affects the speed of electrical machining. Therefore, it is necessary to select good graphite electrode materials according to different technological conditions. Graphite electrode has high melting point, because of its high heat resistance, can improve the current value, reduce electrode loss, further improve production efficiency; When the current value is very small, the electrode loss will increase. When the area and pulse width remain unchanged, the peak current will reach a certain value and continue to increase, resulting in machining instability. Electrode and machining process will produce arc burn, which will greatly reduce the production efficiency.

The larger the current of the graphite electrode, the larger the pits. So, as the peak current increases, the surface gets rougher. At the beginning, the chip electrode and the workpiece are almost point contact, small electrode can not withstand too much current, easy to damage. Therefore, at the beginning, the current should be turned down, and then slowly increase the peak current until the discharge is stable and the processing speed is fast.