How much does the selection of ceramic balls affect the grinding?

People in the industry know that the ceramic balls of the sander is mostly glass beads, steel beads, zirconium silicate beads, ceramic balls, pure zirconia, etc., and the ceramic balls is one of the important factors affecting the efficiency of the sander.So in the face of a wide variety of grinding media, different sizes, how we choose the right grinding media has become the core problem to solve.

The influence of the selection of ceramic balls on grinding

ceramic ball

(1) Hardness

Mohs hardness and Vickers hardness are commonly used as indicators. In general, the higher the hardness of the ceramic balls, the lower the wear rate of the bead.From ceramic balls for sand mill contact element (dispersion plate, rod pin and cylinder, etc.) within the wear, hardness of ceramic balls to wear larger contact element, the smooth surface of the beads on the cylinder and diffuse plate wear is relatively small, at the same time can be adjusted by grinding beads filling amount, material parameters such as viscosity, flow so as to achieve better optimization point.

(2) particle size

The size of the ceramic balls determines the number of contact points between the bead and the material. The more contact points the beads with small particle size have in the same volume, the more effective collision times they have in the grinding process, and the higher grinding efficiency they will have.At the same grinding time, the product fineness is better when using small diameter grinding bead than using large diameter ceramic balls.But on the other hand, when grinding the material with relatively large initial particles, such as the material of 100 microns, D=1mm beads may not be preferable, the reason is that the impulse of small beads can not reach the full energy of grinding dispersion, at this time should use larger particle size beads.

(3) Density

Density is expressed in terms of density (true density) and bulk density (false density) in common documents. The molecular weight and percentage composition of various oxides determine the density of ceramic balls. Under normal conditions, the higher the density of ceramic balls, the greater the kinetic energy generated with the rotation of sanding machine, and the higher the grinding efficiency.But on the other hand, the greater the density of the ceramic balls, the greater the wear of the contact parts of the sanding machine (inner cylinder, dispersion plate, etc.) is relatively large, so the match of the viscosity and flow of the material becomes the key.Low density ceramic balls is suitable for low viscosity material, high density ceramic balls is suitable for high viscosity material.

ceramic balls

2. Reasonable filling rate

The ceramic balls filling rate is the number of beads required by the sander for better dispersion.The filling rate of the grinding bead is too high, which easily causes the internal temperature of the sander to rise, and the cylinder can not heat away in time and automatically shuts down.The filling rate of the grinding bead is too low, the grinding efficiency is low, and the medium loss is large.Therefore, reasonable filling rate is one of the important factors to improve the grinding efficiency.

In the manual of sand mill, the filling rate is often expressed by the volumetric method, but in production, it must be converted into the actual filling quality of the medium.Calculation formula = effective volume of sand mill × filling rate × bulk density of ceramic balls

Two, add ceramic balls

1, adding the principle of ceramic balls

If the grinding efficiency of the grinding machine is found to be reduced, it is a possible signal to add beads.Users can master the actual loss rate of beads according to their own process conditions, and make regular sieve and add beads.

2, how to add ceramic balls

Due to the natural loss of beads, beads particle size will be smaller and smaller, in order to maintain a uniform filling amount and avoid fine beads clogging or entering the separation device, should be based on the life of the ceramic balls and the user’s own process conditions to screen the beads and add a certain amount of ceramic balls.Shanghai Routt recommends checking for wear after 500 to 600 working hours and adding a reasonable amount of new beads.

 

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Post time: Apr-27-2021
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