graphite rod electrode high quality

As high quality graphite electrode material, it is first necessary to conduct electricity and heat. In electrical discharge machining, due to partial discharge, the gap temperature between the HP graphite electrode and the workpiece is 2000 to 3000℃, so the high purity graphite electrode material needs to be exposed to high temperatures. If the melting point of the electrode material is relatively low, high current cannot be used for rapid processing, resulting in a low processing speed and increased processing costs. Theoretically, tungsten or tungsten alloys are the best electrode materials. Tungsten electrodes feature high strength, high density and a melting point close to 3400℃. In electrical discharge machining, the practical loss of tungsten electrodes is very small. Ultrafine graphite is a new type of graphite material developed in the 1970s, mainly used for the precision processing electrodes of electrical discharge machines.

 

However, tungsten electrodes have two problems: 1. Tungsten is very difficult to process. 2. Expensive. Since the 1960s, fine-structured graphite has been selected as the electrode material for rough machining on electrical discharge machining (EDM) machines. In the electrode materials used in electrical discharge machining (EDM) machines in the 1960s, metal materials accounted for 80%, while graphite materials only made up 20%.

 

Compared with copper electrodes, UHP graphite electrodes have obvious superiority.

 

The first one is the addition speed. The volume of metal etching per hour is called the processing speed. The processing speed of ultrafine graphite electrodes is 1.5 to 3 times faster than that of copper electrodes. It can be processed over a large area under high current conditions. However, because the melting point of copper electrodes is relatively low, their processing current is limited.

 

Moreover, the common force of the workpiece contour after processing is the machining accuracy, which is closely related to whether the electrode material is wear-resistant. During electrical discharge machining, there are several kinds of losses of electrode materials. Among the four types of losses, namely volume loss, end face loss, side face loss and corner loss, corner loss is the largest. The magnitude of corner loss determines the service life of the electrode. Because the final processing wheel is determined by the electrode wear at the corners and edges of the electrode, if the weakest part of the electrode can effectively resist the wear, the electrode will have the longest service life.

 

The melting point of ultrafine graphite rods is 2000℃ higher than that of copper. The strength of ultrafine graphite rods is higher than that of copper, and the corner loss during processing is very small. This means that the service life of ultrafine graphite is long and the processing cost is lower than that of copper electrodes.

 

Secondly, it can perform highly precise processing. On a 13×13mm ultrafine graphite rod, 2,813 holes with a diameter of 0.02mm can be drilled, and the distance between each hole is 0.05mm. However, copper, which has a lower strength than ultrafine graphite, is unable to achieve such precise processing.