Electrical discharge machining (EDM) is a precision machining technology widely used in the mold manufacturing industry, and graphite plates are often used as electrodes in EDM.
Performance requirements for graphite plates used in electrical discharge machining
1. The surface of the processed graphite mold is required to have a dense and uniform structure, without any pores, because the precision of the graphite mold surface directly affects the surface precision of the resulting metal mold.
2. The graphite plate must have sufficient mechanical strength to be processed into the required sharp edges, thin walls, and other shapes without breaking.
3. Large graphite plates are made by joining multiple graphite blocks, and the performance of each joined block must be essentially consistent.
4. Isotropic properties are required. Therefore, fine-grained graphite plates produced by isostatic pressing are better than those produced by die pressing, but the former are more expensive, so die-pressed fine-grained graphite is still used in electrical discharge machining. Due to the anisotropy of die-pressed graphite, graphite plate manufacturers must pay attention to directionality during processing.
5. For molds requiring high surface precision, ultra-fine-grained graphite plates/rods made by isostatic pressing with particle sizes of less than 1 μm, or even 1-2 μm, are used as tool electrodes.