1. Introduction of the graphite electrode
The graphite electrode refers to the high-temperature resistant graphite conductive material made by using petroleum coke and asphalt coke as aggregates and coal tar pitch as binder through the process of raw material calcination, crushing and grinding, batching, kneading, molding, roasting, impregnation, graphitization and mechanical processing. It is called the artificial graphite electrode (referred to as the graphite electrode) to distinguish it from the natural graphite electrode prepared by using natural graphite as raw material.
The main raw material for graphite electrode production is petroleum coke. A small amount of asphalt coke can be added to ordinary power graphite electrodes, and the sulfur content of petroleum coke and asphalt coke should not exceed 0.5%. Needle coke also needs to be added when producing high-power or ultra-high-power graphite electrodes. The main raw material for aluminum anode production is petroleum coke, and the sulfur content should be controlled not to exceed 1.5% to 2%. Also, petroleum coke and asphalt coke should meet the relevant national quality standards.
2. Advantages of the graphite electrode
(1) Due to the increasing complexity of die geometry and the diversification of product applications, the discharge accuracy of spark machines deserves higher and higher requirements. The advantages of graphite electrodes are that it is easy to be processed, it has high discharge machining removal rate, and there is little graphite loss. Therefore, some customers of group-based spark machines have abandoned copper electrodes and switched to graphite electrodes. In addition, some special-shaped electrodes cannot be made from copper, but graphite is easier to shape. Moreover, the copper electrode is heavier and not suitable for processing large electrodes. These factors have contributed to the application of graphite electrodes by some customers of group-based spark machines.
(2) The graphite electrode is easier to process, and the processing speed is significantly faster than that of the copper electrode. For example, by adopting the milling technology to process graphite, the processing speed is 2 to 3 times faster than that of other metal processing technology and no additional manual processing process is required. However, the copper electrode requires manual grinding. Similarly, if a high-speed graphite machining center is used to manufacture electrodes, the speed will be faster, the efficiency will be higher, and there will be no problems related to the dust.
(3) The design of the graphite electrode is different from that of the traditional copper electrode. Many die factories usually have different reservations for roughing and finishing of copper electrodes. However, the graphite electrode uses almost the same amount of reservation. This reduces both the CAD/CAM and the processing times by using the machine. For this reason alone, it is enough to greatly improve the accuracy of the die cavity.