Properties of Graphite Electrode Materials

Ⅰ. Characteristics of graphite electrode materials

1. Fast CNC machining, high machinability, and easy trimming

The processing speed of graphite electrodes is fast, which is 3-5 times that of copper electrodes, and the finishing speed is particularly outstanding. And its strength is very high, for ultra-high (50-90mm), ultra-thin (0.2-0.5mm) electrodes, it is not easy to deform during processing. Moreover, in many cases, the product needs to have a good textured surface effect, which requires making an integral public electrode as much as possible when making the electrode, and there are various invisible clear angles when making the integral public electrode. Due to the easy-to-treat nature of graphite, this challenge is easily solved and the number of electrodes is greatly reduced, which is not possible with copper electrodes.

2. Light; low cost

In the production cost of a set of molds, the CNC machining time, EDM time, electrode loss, etc. of the electrode account for the vast majority of the overall cost. And these are determined by the electrode material itself. Compared with copper, graphite electrode processing speed and EDM speed are 3 to 5 times that of copper. At the same time, the characteristics of minimal wear and the production of integral male graphite electrodes can reduce the number of electrodes, which also reduces the consumables and machining time of the electrodes. All of these can greatly reduce the production cost of the mold.

3. Rapid EDM forming, small thermal expansion, and low loss

Since graphite has better conductivity than copper, its discharge rate is 3 to 5 times faster than that of copper. And it can withstand a large current during discharge, which is more beneficial when EDM roughing. At the same time, under the same volume, the weight of graphite is 1/5 times that of copper, which can greatly reduce the load of EDM. It is very advantageous for making large electrodes and integral public electrodes. The sublimation temperature of graphite is 4200°C, which is 3 to 4 times that of copper (the sublimation temperature of copper is 1100°C). At high temperatures, the deformation is very small (1/3~1/5 of copper under the same electrical conditions), and it does not soften. The discharge energy can be transferred to the workpiece with high efficiency and low consumption. Since the strength of graphite increases at high temperatures, it can effectively reduce the discharge loss (the loss of graphite is 1/4 of that of copper), which ensures the processing quality.

Ⅱ. Graphite electrodes inevitably replace copper electrodes

In recent years, with the introduction of precision molds and high-efficiency molds (the molding cycle is getting shorter and shorter), people's requirements for mold making are getting higher and higher. Due to the limitations of various conditions of the copper electrode itself, it has become more and more unable to meet the development requirements of the mold industry. As an EDM electrode material, graphite has been widely used in the mold industry due to its high machinability, lightweight, fast forming, extremely small expansion rate, low loss, and easy trimming. Therefore, it has become inevitable to replace copper electrodes with graphite electrodes.