Advantages of graphite materials in EDM processing

In the past, EDM in mold manufacturing generally used copper as the electrode material. With the increase in the price of copper materials and the advancement of graphite technology, the price of graphite materials has been reduced, and graphite is increasingly widely used as electrode materials for electrical discharge machining. Compared with copper, graphite materials have various advantages.

1. Good machinability

The cutting resistance of graphite material processing is smaller, and its processing efficiency is about 2~3 times that of copper. The use of graphite material can effectively shorten the processing time of the electrode.

2. It is easier to realize the processing of thin rib shape

The cutting heat generated by the processing of copper electrodes is prone to thermal deformation. Due to the characteristics of its plastic material, it is also prone to elastic deformation when processing thin rib shapes, causing processing vibrations; while graphite itself is made of sintered particles, and its heat-resistant and brittle material properties can reduce deformation and vibration during processing.

3. Excellent EDM roughing efficiency

The melting point of copper is 1083 °C, and the instantaneous temperature of discharge can reach 1100 °C. It is easier to wear copper electrodes, and graphite will sublime at 3550 °C, therefore, the graphite electrode is easier to withstand high current, and can achieve smaller electrode loss.

4. Lighter weight

The density of graphite is only 1/5 of that of copper, and the use of graphite electrodes can greatly reduce the load on the machine head during EDM machining.

5. Small thermal expansion rate

The thermal expansion rate of graphite is 1/4 of that of copper, which can effectively reduce the error caused by the thermal deformation of the electrode during discharge.