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Three reasons affecting the surface quality of EDM materials

 EDM is also a mold processing technology, which is mainly processed by the high voltage generated by the discharge between the two electrodes. 

It can be applied to the processing of many materials, but different materials can easily cause the quality of the material surface. Look at the three reasons that affect the quality of the processed surface.

1. Electrical discharge machining microhardness and wear resistance

For some hardened steels, the hardness of the surface layer is usually higher, and may be slightly lower than the hardness of the matrix.

For rolling friction, because it is an alternating load, especially dry friction, the melt-solidified layer and the basic bond are not strong, and it is easy to peel and wear. Therefore, some molds with high requirements need to be ground off before EDM.

2. Residual stress in EDM

There are residual stress on the surface, most of which are tensile stress. The magnitude and distribution of residual stress are mainly related to the heat treatment state of the material before treatment and the pulse energy during treatment. Therefore, it should be avoided as much as possible to have high-quality workpieces in the surface layer.

3. EDM processing fatigue resistance

The surface has great tensile stress and may have micro-cracks. The fatigue resistance is many times lower than that of the machined surface. This helps reduce residual stress or convert residual tensile stress into compressive stress, thereby improving fatigue resistance.

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