The called Mesh Number represents the granularity or particle size of the abrasive materials in the brush bristles. In general, Mesh Number means the number of meshes in one area of“1 inch * 1 inch” in one screen. If one kind of abrasive material can pass one screen of “n” meshes, then it shall be defined as a grinding material of “n” mesh. For example, Grinding material of“320” mesh can pass one screen with 320 meshes every “1 inch * 1 inch”. Thus, the larger the mesh number of one grinding material is, the smaller the particle size of the material is, and vice versa.

Additionally, grinding materials are divided into two categories generally, i.e., carborundum (SiC) and alumina (Al2O3).

In the PCB industry, generally, there is a corresponding relationship between the mesh number of grinding brush roller and the diameter of brush bristle. For example, 320# brush roller corresponds to a brush bristle diameter of φ0.6mm,and 500# brush roller φ0.5mm.