The M7475B surface grinder is a circular electromagnetic table, a vertical grinding head, and a high-efficiency grinding machine that uses a grinding wheel end face for grinding. In the course of use, it is easy to encounter fatigue wear when the electromagnetic suction cup and the withdrawal sleeve contact, if not repaired in time, Not only does it not guarantee the dimensional accuracy of the workpiece being ground, but it also reduces the life of the electromagnetic chuck. The schematic diagram of the electromagnetic chuck structure is shown in Figure 1.