Grinding wheel is the main tool for grinding. It is a porous object composed of abrasive and bonding agent. Among them, abrasive, bond and substitution are the three basic components of the grinding wheel. The characteristics of the grinding wheel may vary greatly through the difference in abrasives, bonding agents, and grinding wheel manufacturing processes, which have an important impact on the accuracy, size and production efficiency of the grinding process. Therefore, the appropriate grinding wheel must be selected according to specific conditions.
Abrasive is the main raw material for making grinding wheels, it is responsible for cutting work. Therefore, the abrasive must be sharp, while having high hardness, good heat resistance and certain advantages. The name, code, characteristics and uses of commonly used abrasives.
Particle size refers to the size of abrasive particles. The particle size is divided into two groups: abrasive particles and micro powder. Abrasive grains are classified by the screening method, and its particle size number is expressed by the number of holes within one inch of the screen. For example, 60 # grain size, means that it can pass through a screen with 60 holes per inch, but cannot pass through a screen with 70 holes per inch. Micropowder is classified by microscopic measurement, and its particle size number is expressed by the actual size of the abrasive ( W ).
The choice of abrasive particle size is mainly related to surface roughness and productivity.
In rough grinding, the grinding allowance is large and the required surface roughness value is larger, so coarser abrasive grains should be used. Because the abrasive grains are coarse and the pores are large, the grinding depth can be larger, and the grinding wheel is not easy to block and generate heat. In fine grinding, the margin is small and the roughness value is required to be low, so finer abrasive grains can be selected. Generally speaking, the finer the abrasive grains, the better the grinding surface roughness.