Views: 0 Author: Site Editor Publish Time: 2021-08-18 Origin: Site
one. The general category of polishing powder:
Polishing powder is usually composed of aluminum oxide, silicon oxide, zirconium oxide, cerium oxide and other components. Different materials have different hardness and chemical properties in water, so the use occasions are different. Alumina and zirconia have a Mohs hardness of 9, cerium and silicon oxide have a Mohs hardness of 7, and iron oxide is even lower.
two. Basic requirements for polishing powder:
(1) The particle size of the micropowder is uniform and within the allowable range;
(2) It has high purity and does not contain mechanical impurities;
(3) It has good dispersibility to ensure the uniformity and efficiency of the processing process, and an appropriate amount of dispersant can be added to increase the suspension rate;
(4) The powder particles have a certain crystal lattice shape, which forms sharp edges and corners when broken to improve polishing efficiency;
(5) It has suitable hardness and density, and has good wettability and suspension with water, because the polishing powder needs to be mixed with water
The larger the particle size of the polishing powder, the greater the grinding force, and the more suitable it is for harder materials.
The particle size of some polishing powders has a distribution problem. The average particle size or the median diameter D50 only determines the polishing speed, while the maximum particle size Dmax determines the polishing accuracy. Therefore, in order to obtain high-precision requirements, the maximum particle size of the polishing powder must be controlled. The reason why ordinary polishing powder has scratches is due to the large particles. So generally choose nano polishing powder (VK-L30F) with a narrow particle size distribution range. The finer the polishing powder, the higher the brightness of the polished material.
The concentration of the slurry in the polishing process determines the polishing speed, the greater the concentration, the higher the polishing speed. When using small-particle polishing powder, the slurry concentration should be appropriately adjusted to obtain suitable fluidity. Generally, it is recommended to be 7-10%
three. Selection of polishing mold
The polishing mold should be softer. It should be pointed out that cerium oxide polishing powder is added to many polyurethane polishing sheets. The maximum particle size of these polishing powders also determines the final polishing accuracy. Generally, it is best to use a polishing mold without polishing powder. There are sponge wheels, wool wheels and so on.
Four. Indexes that affect the performance of polishing powder
1. The particle size of the powder: The size and uniformity of the particles determine the polishing speed and precision. The number of screen meshes can grasp the value of the relative particle size of the powder, and the average particle size determines the overall level of the particle size of the polishing powder.
2. Powder Mohs hardness: The powder with relatively high hardness has a faster cutting effect, and adding some grinding aids can also improve the cutting effect; different application fields will have great differences, including its own processing technology .
3. Powder suspension: A good polishing powder must have better suspension. The shape and particle size of the powder have a certain influence on the suspension performance. The suspension of nano-particle polishing powder is relatively better, so it is more refined. Generally choose nano polishing powder for polishing.
4. The crystal form of the powder: The crystal form of the powder is agglomerated single crystal particles, which determines the machinability, wear resistance and fluidity of the powder. The single crystal particles agglomerated together are separated during the polishing process, so that the machinability and wear resistance are gradually reduced. The spherical polishing powder has good machinability, wear resistance and fluidity.
Fives. Subdivision of polishing range:
As fine polishing materials, the most used types of polishing powders currently on the market are mainly alumina polishing powders, cerium oxide polishing powders, and silicon oxide polishing powders.
1. Alumina polishing powder:
Alumina polishing powder (VK-L30F) is generally used for stone polishing, aluminum mirror polishing, stainless steel mirror polishing, cast iron polishing, titanium alloy polishing, metallographic analysis, automotive paint mirror polishing, resin polishing, gem polishing, spherical particles, The particle size is 0.3um.
2. Silica polishing powder:
It is generally used for artificial crystals, gem polishing, or metal products to repair a small amount of flaws after polishing. Its particle size is generally 50nm
3. Cerium oxide polishing powder or polishing liquid (VK-Ce01W):
Used for polishing lenses, TV picture tubes, spectacle lenses, wafers, optical components, optical fibers, art glass, electronic glass, flat glass, etc. The primary particle size is generally required to be 20-30nm, and the secondary particle size is generally required to be 0.2um.