Electrical discharge machining (EDM) machines are tools for processing, but during the machining process, various issues may arise due to other factors. One cannot simply pursue speed; if the speed is too fast, it may lead to increased wear of the electrodes or greater roughness. So, what are the factors that affect the machining quality of EDM machines?

Factors affecting the surface quality of EDM machines

1. The microhardness and wear resistance of the workpiece processed by EDM machines. The hard surface layer is usually higher than that of certain hardened steels but may be slightly lower than the hardness of the substrate. It is used for rolling friction, and due to alternating loads, especially dry friction, wear occurs because the molten solidified layer and the basic combination are not firmly bonded, making it easy to peel off. Therefore, some demanding molds require processing after grinding the surface altered layer.

2. Residual stress in the machining of EDM machines. Surface residual stress exists, and the magnitude of most tensile stresses and the distribution of residual stresses, as well as the heat treatment of the main material and the processing of pulse energy, should be considered beforehand. Therefore, for workpieces with higher quality requirements on the surface layer, excessive processing methods should be avoided.

3. Fatigue resistance of the workpiece processed by EDM machines. The surface may have significant tensile stress, which can lead to micro-cracks. The fatigue strength of the surface is much lower than that of the processed surface. Tempering treatment, shot peening, and other methods help reduce residual stress or convert residual tensile stress into compressive stress, thereby improving fatigue resistance.