The choice of particle size depends primarily on the surface roughness and grinding efficiency of the workpiece being ground.
Particle size refers to the particle size of the abrasive and its size is indicated by the particle size number. When grinding with a coarse-grained cutting piece, the production efficiency is high, but the surface of the ground workpiece is rough; when grinding with a fine-grained cutting piece, the surface of the machined workpiece has better surface roughness and lower productivity. Under the premise of meeting the roughness requirements, coarse-grained customized metal cutting disc should be used as much as possible to ensure high grinding efficiency. Generally, coarse-grained cutting sheets are used for rough grinding, and fine-grained cutting sheets are used for fine grinding. Metal processing WeChat, the content is good, it is worthy of attention.

When the contact area between the cutting piece and the workpiece is large, a cutting piece having a coarser grain size is selected. For example, grinding the same plane, the end face grinding with the cutting piece is coarser than the grain size selected by the peripheral grinding of the cutting piece.

The choice of hardness depends primarily on the material being ground, the grinding efficiency and the quality of the machined surface.
Hardness refers to the difficulty of the abrasive grains falling off under the action of external force. In order to meet the requirements of different workpiece material grinding, the cutting sheets are divided into different hardness grades.

The cutting piece is selected too hard, the blunt abrasive grains are not easy to fall off, the cutting piece is easy to block, the grinding heat is increased, the workpiece is easy to burn, the grinding efficiency is low, and the surface quality of the workpiece is affected; the cutting piece is selected too soft, and the grinding grain is still sharp. When it falls off, it increases the loss of the cutting piece, and it is easy to lose the correct geometry and affect the accuracy of the workpiece. Therefore, the selection of the hardness of the cutting piece should be appropriate, and should be comprehensively considered according to the contact area of ​​the cutting piece and the workpiece, the shape of the workpiece, the way of grinding, the cooling method, the type of bonding agent of the cutting piece and the like.

The following cutting blade hardness selection principles are for reference:
a. When grinding soft materials, choose a harder cutting piece. When grinding hard materials, choose a soft cutting piece.
b. When grinding soft and tough non-ferrous metals, the hardness should be selected to be softer;
c. Grinding materials with poor thermal conductivity should be selected as softer cutting blades;
d. When the end face grinding is more than the circumferential grinding, the hardness of the cutting piece should be selected softer;
e. Under the same grinding conditions, the hardness of the cutting piece with the resin bond is 1~2 lower than that of the ceramic bond cutting piece;
f. When the cutting speed of the cutting piece is high, the hardness of the cutting piece can be softly 1~2 small;
g. Grinding with coolant is 1~2 less than the hardness of the cutting piece during dry grinding.