Grinding wheel is the most important type of abrasive tool in grinding process. The grinding wheel is a porous body made by adding a bonding agent to the abrasive, and then forming a compact, drying and roasting. Due to the different abrasives, bonding agents and manufacturing processes, the characteristics of the grinding wheels are very different, which has an important impact on the grinding processing quality, productivity and economy. The characteristics of the grinding wheel are mainly determined by factors such as abrasive, strength, bonding agent, hardness, organization, shape and size.

There are many kinds of grinding wheels.

According to the abrasives used, it can be divided into ordinary abrasive (corundum and silicon carbide, etc.) grinding wheels, natural abrasive super-hard abrasives and (diamond and cubic boron nitride, etc.) grinding wheels;

According to the shape, it can be divided into flat grinding wheels, beveled grinding wheels, cylindrical grinding wheels, cup-shaped grinding wheels, dish-shaped grinding wheels, etc.; according to the bonding agent can be divided into ceramic grinding wheels, resin grinding wheels, rubber grinding wheels, metal grinding wheels, etc. The characteristic parameters of the grinding wheel mainly include abrasive, viscosity, hardness, bonding agent, shape, size and so on.

Since the grinding wheel usually works at high speed, it is necessary to carry out a rotation test (to ensure that the grinding wheel will not break at the highest working speed) and a static balance test (to prevent vibration of the machine tool during work) before use. After working for a period of time, the grinding wheel should be trimmed to restore the grinding performance and correct geometry.

The characteristics of the grinding wheel used on the grinder are:

Due to severe friction, the temperature in the grinding zone is very high. This will cause stress and deformation of the workpiece, and even cause burns on the surface of the workpiece. Therefore, a large amount of coolant must be injected during grinding to reduce the grinding temperature. Coolant can also play a role in chip removal and lubrication.

The radial force during grinding is very large. This will cause the elastic retreat of the machine tool-grinding wheel-workpiece system, making the actual depth of cut less than the nominal depth of cut. Therefore, when the grinding is about to be completed, smooth grinding should not be carried out to eliminate the error.

After the abrasive grains are blunt, the grinding force increases, causing the abrasive grains to break or fall off, revealing the sharp edge again. This characteristic is called "self-sharpening". Self-sharpening enables the grinding to be carried out normally within a certain time, but after a certain working time, manual trimming should be carried out to avoid vibration, noise and damage to the surface quality of the workpiece caused by the increase of the grinding force.

Because the abrasive grains of the grinding wheel have high hardness and heat resistance, the grinding can process materials with high hardness, such as hardened steel and cemented carbide.

The characteristics of the grinding wheel and the grinder determine that the grinding process system can make uniform micro-cutting, generally ap=0.001～0.005mm; the grinding speed is very high, generally up to v=30～50m/s; the rigidity of the grinder is good; it adopts hydraulic transmission, Therefore, grinding can economically obtain high machining accuracy (IT6～IT5) and small surface roughness (Ra=0.8～0.2μm). Grinding is one of the main methods of finishing parts.