**1 Workpiece Clamping** On a surface grinder, an electromagnetic chuck table is used to secure the workpiece. The working principle of the electromagnetic chuck involves passing direct current through a coil, which magnetizes the core. This creates a magnetic field that closes through the cover plate, the workpiece, and the base plate, effectively holding the workpiece in place. The magnetic layer of the electromagnetic chuck is typically made from non-magnetic materials such as lead, copper, or alloys. These materials help guide the majority of the magnetic flux through the workpiece, ensuring strong and even attraction.  **Figure 1: Principle of the electromagnetic chuck structure** When grinding small components like keys, washers, or thin-walled sleeves, the contact area between the workpiece and the chuck is often limited, resulting in weaker suction force. This can cause the workpiece to be accidentally ejected by the grinding force. To prevent this, it's important to surround or enclose the workpiece with a fence on both ends during clamping. This helps maintain stability and prevents movement during the grinding process.  **Figure 2: Clamping workpiece** **2 Grinding Methods**  **Figure 3: Plane grinding method** 1) **Side Grinding** As shown in Figure 3a, side grinding involves feeding the grinding wheel horizontally after each longitudinal stroke of the worktable. Once the first layer of material is removed, the wheel is fed vertically according to the pre-set depth. This process is repeated layer by layer until the desired size is achieved. During rough grinding, larger vertical and horizontal feeds are recommended, while finer feeds are used for finishing. This method is ideal for long and wide workpieces, as well as for grinding multiple small parts arranged in order. 2) **Deep Grinding** As illustrated in Figure 3b, deep grinding uses minimal longitudinal feed. The grinding wheel makes only two vertical feeds. The first one corresponds to the total rough grinding allowance after the worktable completes its travel. Then, the wheel is moved laterally by about 3/4 to 4/5 of its width until the entire surface is ground. The second vertical feed is equal to the final grinding allowance. This method reduces the number of vertical feeds, increases productivity, and ensures better quality. However, it generates higher grinding resistance and is best suited for large workpieces on heavy-duty, rigid grinders. 3) **Step Grinding** As shown in Figure 3c, step grinding involves shaping the grinding wheel into a stepped profile based on the workpiece dimensions. This allows the entire excess material to be removed in a single vertical feed. Each step should have the same width and depth for rough grinding, while the fine grinding step should be wider than half the wheel width, with a depth equal to the final grinding allowance (0.03–0.05 mm). Lateral feed should be kept small. Since the grinding load is distributed across the different steps, the abrasive grains wear more evenly, maximizing the performance of the grinding wheel. However, dressing the wheel for step grinding can be more complex, limiting its use in certain applications.

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