A grinder is a grinding machine that uses a grinding tool coated or embedded with abrasive to grind the surface of a workpiece. Mainly used for grinding high-precision flat surfaces, inner and outer cylindrical surfaces, conical surfaces, spherical surfaces, threaded surfaces, and other profiles in workpieces.

Analysis of Factors Affecting Sand Grinding Efficiency

Density of grinding beads

In general, the larger the specific gravity of the grinding beads, the greater the impulse and the higher the grinding efficiency. However, the contact parts of the sand mill (such as the inner cylinder and dispersion disk) are relatively worn, so the combination of viscosity and flow rate of the slurry becomes crucial. Low density grinding beads are suitable for low viscosity slurries, while high-density grinding beads are suitable for high viscosity slurries.

Hardness of grinding beads

The higher the hardness of the grinding beads, the theoretically lower the wear rate of the beads. From the perspective of the wear of the contact parts (dispersing disc, rod pin, inner cylinder, etc.) of the sand mill by the grinding beads, although the grinding beads with higher hardness have greater wear resistance to the contact parts, the optimal optimization point can be achieved by adjusting the filling amount of the beads, viscosity, flow rate and other parameters of the slurry.

Particle size of grinding beads

The size of the grinding bead determines the number of contact points between the grinding bead and the material. Beads with smaller particle sizes have more contact points at the same volume, theoretically resulting in higher grinding efficiency; On the other hand, when grinding materials with relatively large initial particles, such as for a 100 micron slurry, D=1mm beads may not necessarily be used because the impulse of small beads cannot achieve sufficient energy for grinding and dispersion. In this case, larger particle size beads should be used.

Grinding medium particle size

There are different conclusions among researchers regarding the uniformity of grinding media, with one theory suggesting that the diameter of the grinding media should be consistent. From a dynamic perspective, when the diameter of the medium is the same and the volume is the same, the mass is equal, that is, m1=m2, and the same momentum m1v1=m2v2 can be obtained in motion; When m1>m2, m1v1>m2v2， When two balls collide, the big ball will push the small ball apart, causing the big ball to chase the small ball and reducing the grinding effect. Another statement is exactly opposite to the previous conclusion. From a geometric perspective, it is believed that mixing grinding media of different diameters, with small media filling the gaps of large media, increases the number of contact points between media, and thus improves grinding efficiency.

In addition, the final particle size of the grinding material is determined by the grinding blind zone (gap). If the size distribution of the grinding medium is narrower, the particle size distribution of the ground material will also be relatively narrower.

Grinding medium ball smoothness

The grinding medium is mixed with the slurry and loaded into the grinding chamber. While grinding and crushing the material, the medium will also experience some wear. After the worn material enters the slurry, it is difficult to separate it using conventional methods, which affects product quality and even changes the color of the material. This is not desirable for producers. For the same material, the wear rate is directly proportional to the surface smoothness of the grinding medium, so it is required that the surface of the grinding medium be smooth to reduce the wear rate.

Selection of Grinding Medium Ball Size

Choose zirconium beads or glass beads based on the viscosity of the material, and select beads of appropriate size according to the particle size of the raw material and the required fineness of the product. Check if the separator or sieve aperture of the grinder is set appropriately, and the gap should be one-third of the minimum bead diameter. Try to avoid turning on the grinder in a dry state, which may cause unnecessary loss of beads and accessories . Different brands of beads cannot be mixed for use . Try to avoid mixing beads of different sizes.