What are the advantages and characteristics of graphite electrodes in EDM?

I. The increasing complexity of the mold geometry and the diversification of the application of the products concerned lead to higher and higher requirements for the machining and discharge accuracy of the EDM electrodes. Graphite electrodes have the advantage of easier processing, high removal rate of discharge machining, graphite loss is small, therefore, more and more mold makers give up the copper electrode and switch to graphite electrodes. In addition, some special shape of the electrode can not be manufactured with copper, but graphite is easier to mold, and copper electrode is heavier, not suitable for processing large electrodes, these factors have accelerated the graphite electrode in the mold manufacturing industry more and more widely used.

Two, graphite electrode is easier to process, and processing speed is significantly faster than copper electrode. For example, the use of milling process processing graphite, its processing speed than other metal processing 2 to 3 times faster and does not require additional manual processing, while the copper electrode needs to be manually thwarted grinding. Similarly, if a high-speed graphite machining center is used to make the electrodes, it is faster and more efficient, and does not create dust problems. During these processes, the selection of tools and graphite with the right hardness reduces tool wear and electrode breakage. If you specifically compare the milling time of graphite electrodes and copper electrodes graphite electrodes, graphite is 67% faster than copper electrodes, and in the general case of electrical discharge machining, machining with graphite electrodes is 58% faster than with copper electrodes. In this way, the processing time is significantly reduced, while also reducing manufacturing costs.

Third, graphite electrode and traditional copper electrode design is different. Many mold makers usually have different allowances for roughing and finishing of copper electrodes, while graphite electrodes use almost the same allowances, which reduces the number of CAD/CAM and machine processing, which alone is enough to improve the accuracy of the mold cavities to a large extent.

Of course, the first thing that should be clear to a mold maker after switching from copper electrodes to graphite electrodes is how to use the graphite material as well as consider other relevant factors. Nowadays, most of the plastic products of the mold using graphite to electrode discharge processing, which eliminates the mold cavity polishing and chemical polishing process but still can achieve the desired surface finish. This is not possible with copper electrodes without increasing the time and polishing process. In addition, graphite is classified into different grades, and it is necessary to use the appropriate grade of graphite and spark machine discharge parameters to achieve the desired processing results in a particular application. If the operator uses the same parameters in a spark machine using graphite electrodes as in the case of copper electrodes, the results will certainly be disappointing. If you want to tightly control the material of the electrode, you can set the graphite electrode in the roughing in a non-depleting state (less than 1% loss), but copper electrodes are not used.