7. Low electrode wear ratio
It is said that the temperature of the spark generated by EDM is about 6000 degrees centigrade. When sparks occur between the electrode and the workpiece, the sparking point is dissolved hot. The spark duration is adjusted between 1/1,000,000 second and 1/1,000 second, and longer duration makes dissolving larger.
Both the electrode and the workpiece are supposed to be dissolved hotly similarly by the outbreak of the spark. Reducing the wear by dissolution of the electrode is necessary for transcribing the shape of the electrode efficiently. Therefore, the materials which are hard to dissolve are suitable for the electrode, and the workpiece of more easily dissolved material can be processed more efficiently.
Currently, copper is used most as a material of the electrodes, and copper is a material which is good for heat conduction and tough for partial dissolution. It is mostly used to process iron workpiece. Iron is a material comparatively easy to partial dissolution. In the material combination of "copper (electrode) and iron (workpiece)" can make electrode wear ratio less than 1 percent.
Electrode wear ratio [%] = Amount of electrode wear [g] / Amount of work machining [g] × 100
