Note: Graphite electrodes for EDM are also called copper electrodes.
1: The increasing complexity of mold geometries and the diversification of product applications have led to increasingly higher requirements for discharge accuracy of spark machines. The advantages of graphite electrodes are easier processing, high discharge machining removal rate, and low graphite loss. Therefore, some customers of Qunji EDM machines have abandoned copper electrodes and switched to graphite electrodes. In addition, some electrodes with special shapes cannot be made of copper, but graphite is easier to shape, and copper electrodes are heavier and are not suitable for processing large electrodes. These factors have caused some Qunji spark machine customers to use graphite electrodes.
2: Graphite electrodes are easier to process, and the processing speed is significantly faster than copper electrodes. For example, the milling process is used to process graphite, which is 2 to 3 times faster than other metal processing and does not require additional manual processing, while copper electrodes require 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 dust problem. During these machining processes, choosing tools and graphite with appropriate hardness can reduce tool wear and copper breakage. If we specifically compare the milling time of graphite electrodes and copper electrodes, graphite electrodes are 67% faster than copper electrodes. In general discharge machining, machining with graphite electrodes is 58% faster than with copper electrodes. In this way, processing time is significantly reduced, and manufacturing costs are also reduced.
3: The design of graphite electrodes is different from traditional copper electrodes. Many mold factories usually have different reserves for rough machining and finishing of copper electrodes, while graphite electrodes use almost the same reserve, which reduces the number of CAD/CAM and machine processing. This reason alone is enough to improve the accuracy of the mold cavity to a great extent.
After the mold factory switches from copper electrodes to graphite electrodes, the first thing to know is how to use graphite materials and consider other related factors. Nowadays, some customers of Qunji EDM machines use graphite for electrode discharge machining, which eliminates the process of mold cavity polishing and chemical polishing but can still achieve the expected surface finish. It is impossible to produce such a workpiece with copper electrodes without adding time and polishing steps. In addition, graphite is divided into different grades. Only by using the appropriate grade of graphite and spark discharge parameters for a specific application can the ideal processing effect be achieved. If the operator uses the same parameters as copper electrodes on an EDM machine using graphite electrodes, the results will definitely be disappointing. If the material of the electrode needs to be strictly controlled, the graphite electrode can be set to a non-loss state (loss less than 1%) during rough machining, but the copper electrode cannot be used.