How to Choose Grinding Media for Abrasive Sanders

Abrasive Sanders have spherical beaded grinding media. The particle sizes have a narrow range, and the price is inexpensive. Three factors should be taken into consideration when choosing grinding media for abrasive sanders.

1. Diameter of Particles

There is usually a filter screen installed at the sander's exit, at which the scattered sizing agent will get through and the grinding media will be filtered out. So the diameter of the particles should be larger than that of the sieve pore. According to common practice, the diameter of the grinding ball should be 1.5 times larger than that of the sieve pore, or the screen cloth will be blocked. Grinding media with larger sizes are preferred due to the abrasion during the grinding process. Smaller grinding media should be employed to provide more grinding points of contact, that is to say, as long as the particles can provide energy, the pigment will scatter more efficiently.

2. Density

For frequently used vertical sanders, the lower the scattered beads' density, the less the tendency for the beads to submerge or sink to the bottom of the sander and cake, the lighter the abrasion degree of sanders, and the smaller the dispersion force it produces. Therefore, pigment that is easy to disperse or that has smaller agglomerates can adopt particles with smaller density, while pigment that is hard to disperse or with larger agglomerates will achieve a better effect by using high-density particles.

3. Chemical Composites

Care should be taken to make sure all the scattered beads are kept safe and sound during the grinding process. If broken beads occur, it means that the there might be something wrong with the sander. For instance, when the impeller disk is worn and a deep groove is formed, the beads will sometimes become wedged in the groove and be broken.

For emulsion paint production, the most frequently used grinding media are glass beads that are transparent and that have high resistance to wear, which will result in neither excessive wear of the sanders nor the glass beads. The hardness of most glass beads is approximately the same as the wear rate. Other grinding media, such as aluminum oxide balls, zirconium oxide balls, and steel balls, are prone to causing abrasion, especially steel balls, which will make the graining paste turn grey.

Author: Liwei Chu 
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