Diamond slotting knives are better than ordinary slotting knives for the following reasons:

1. High hardness: Diamond is the hardest substance known in nature, so the diamond slotting knife has extremely high hardness and can cope with the slotting task of various high-hardness materials. The hardness of ordinary slotting tool is low, easy to wear and deformation, and can not meet the processing needs of high-hardness materials.
2. Good wear resistance: the chemical properties of diamonds are very stable and not easy to react with other substances, so the wear resistance of the diamond slotting knife is very good and can be used for a long time without excessive wear. In contrast, ordinary slotting knives have poor wear resistance and need to be replaced or sharpened frequently.
3. High processing accuracy: Because the hardness and wear resistance of the diamond slotting knife are excellent, it can ensure high-precision slotting processing. The use of diamond slotting knife can reduce the error in the processing process, improve the processing accuracy, so as to obtain better processing results.
4. Wide range of applications: Diamond slotting knife can process a variety of high hardness, high wear-resistant materials, such as carbide, ceramics, glass and so on. The application range of ordinary slotting knives is relatively narrow, mainly used for processing softer materials.

To sum up, the diamond slotting knife is better to use than the ordinary slotting knife, because it has higher hardness and wear resistance, can guarantee high precision machining, and a wider range of applications.