The fineness of powder is generally expressed by mesh number, which is the unit of length and the size of screen aperture. It represents equal parts within one inch, but the diameter of the screen wire needs to be deducted.

1 micron-12500 mesh

1.3 micron -8000 mesh

2 microns -6250 mesh.

2.6 micron -5000 mesh

5 microns -2500 mesh.

6.5 micron -2000 mesh

10 micron-1250 mesh

15 micron -800 mesh

20 micron -625 mesh.

33 micron -425 mesh.

37 micron -400 mesh

44 micron -325 mesh.

74 micron -200 mesh

149 micron-100 mesh

350 micron -45 mesh

Coarse powder, medium powder, fine powder and superfine powder are used for different requirements. Among plastic powder particles, coarse powder generally refers to 5-60 mesh powder, and medium powder refers to 60- 160 mesh powder. Fine powder 160 mesh to 300 mesh, and above 300 mesh belongs to superfine powder. However, according to the fragile degree of different raw materials, the classification of coarse, medium, fine and superfine is different. For some compounds such as calcium carbonate, 300 mesh can only be regarded as coarse powder.

Ultra-fine and uniform particle size plastic powder overcomes the shortcomings of other powder particles, the uniformity of coating surface and the superiority of light transmission and reflection, so ultra-fine powder particles are more and more widely used in subsequent applications.

Shape requirement

In different production processes, we also have shape requirements for powder particles. The tear powder we usually say is strip-shaped or tadpole-shaped, and its light transmission and reflection properties will lead to uneven color. When sprayed on metal or other surfaces, uneven adhesion will appear after high temperature baking.

The powder produced by impact can be described as pebble-shaped, that is, there is no obvious difference between the longest end and the shortest end. This kind of powder particles can pass through the spray nozzle evenly, which reduces the blockage of the spray nozzle, and has a high degree of atomization and uniform spraying surface. However, the coarse powder particles will affect the uniformity of the spraying surface, and at the same time affect the reflective and light-transmitting properties, thus affecting the appearance and adhesion.

By shaping powder particles, round particles similar to yellow sand can be obtained, that is, stone-shaped particles can be rounded by shaping process, or water chestnut can be melted into whole particles by temperature. This powder particle is first-class in light reflection, light transmission and uniformity. They are the future of plastic powder application.

particle size distribution

Particle size distribution generally refers to the distribution of powder particle size. The narrower the distribution, the better the effect of plastic powder in subsequent production. On the contrary, the wider the distribution, the worse the effect.