The selection of grinding wheels not only affects the processing accuracy and surface quality of the workpiece, but also affects the loss, service life, production efficiency and production cost of the grinding wheel. The following basic principles should be observed in order to achieve the rational selection of grinding wheels:

       (1) Grinding grain should have a good grinding performance.

       (2) The grinding wheel should have a suitable "self-sharpness" when grinding.

       (3) The grinding wheel should not be blunt, has a long service life.

       (4) A smaller grinding force is generated during grinding.

       (5) A smaller grinding heat is generated during grinding.

       (6) Can achieve high processing accuracy (dimensional accuracy, shape accuracy, position accuracy).

       (7) To achieve a small surface roughness value.

       (8) The surface of the workpiece does not produce burns and cracks.

2. Selection of the main characteristics of the external grinding wheel

The outer external grinding wheel is generally a medium-organized flat grinding wheel, while the grinding wheel size is selected according to the machine specifications. The selection of the main characteristics of the outer round grinding wheel includes the choice of grinding grain, hardness and particle size.

       (1) The choice of abrasives is mainly corresponding to the material and heat treatment methods of the processed workpieces. A variety of artificial abrasives are most commonly used in brown corundum and white corundum.

       (2) The choice of hardness, in addition to the general principle of hardness selection, should also be considered for the grinding wheel "self-sharpness" and micro-blade equal high influence.

       (3) The choice of particle size The thickness of grinding grain of the grinding wheel directly affects the roughness of the surface of the workpiece and the grinding performance of the grinding wheel. Finegrains should be selected when grinding, and the opposite

 when roughgrinding. When grinding easy-to-deform workpieces, the particle size should also be selected coarser.