The bead grinding media of the sander should be truly spherical, with a narrow particle size distribution and low cost. In addition, three main factors should be considered: particle size, density, and chemical composition.
A filter screen is provided at the exit of the sand mill, and the dispersed slurry is passed therethrough and the sanding medium must be retained. Therefore, the diameter of the beads must be larger than the diameter of the mesh holes. Experience has shown that the diameter of the grinding balls is at least half the larger than the maximum diameter of the mesh holes, otherwise the screen will often become clogged. Since the beads are inevitably worn during the grinding process, the diameter of the actually used grinding beads should be appropriately enlarged.
Smaller beads should be used as much as possible without clogging the mesh, as it provides more abrasive contact points, that is, as long as the beads provide energy, the pigment will disperse better. density
For the conventional vertical sand mill, the density of the dispersed beads is low, the beads sink and the tendency to sink to the bottom of the sander is less, the wear of the beads and the wear of the sander are also small, but it The resulting dispersion is also small. Therefore, for pigments with low dispersion of pigments and agglomerates, beads with lower density can be used. For pigments with difficult to disperse pigments and agglomerates, high density beads should be used. At this time, the viscosity of the pigment paste should be used. Should be formulated slightly higher to reduce the deposition of beads affecting dispersion. Chemical grade
For latex paint production, the commonly used grinding beads for grinding are glass beads, which are relatively transparent and not very resistant to wear and do not cause excessive wear of the sander. High-strength glass beads also show only moderate wear. The wear products of the glass beads themselves are generally invisible and non-abrasive. Most glass beads have almost the same hardness and wear rate.https://www.wuxiorient.com/