The so-called hardness of diamond grinding wheel refers to the difficulty of the abrasive grains on the diamond grinding wheel to fall off during grinding work. We generally call it the hardness of diamond grinding wheel. Grinding wheels of different hardness are suitable for grinding different workpieces. If the diamond grinding wheel is too hard, the blunt abrasive grains will not fall off in time, which will generate a lot of heat and burn the workpiece; if the grinding wheel is too soft, the abrasive grains will fall off too quickly and cannot fully play their role.

1. The larger the contact surface between the diamond grinding wheel and the workpiece, the softer the diamond grinding wheel should be. Conversely, a grinding wheel with higher hardness should be selected.

2. The harder the workpiece, the softer the diamond grinding wheel should be. The softer the workpiece, the harder the grinding wheel should be.

3. A harder grinding wheel should be selected for fine grinding and profile grinding to maintain the necessary shape accuracy of the grinding wheel.

4. The hardness of the diamond grinding wheel during grinding with coolant is 1~2 grades higher than that during dry grinding.

5. The larger the particle size of the grinding wheel, the softer the grinding wheel should be to avoid being blocked by grinding chips.

6. Under the same grinding conditions, the hardness of the resin bonded diamond grinding wheel is 1~2 grades higher than that of the ceramic bonded diamond grinding wheel.

7. Compared with the circumferential grinding, a softer grinding wheel should be selected for face grinding.

8. When the rotation speed of the diamond grinding wheel is high, the hardness of the grinding wheel can be selected to be 1~2 grades softer.

9. When grinding workpieces with poor thermal conductivity, a softer grinding wheel should be selected;

10. When grinding soft and tough non-ferrous metals, a softer hardness should be selected.