Sieving is a process of separating particles of different sizes. Depends on the size of the particles, different sizes of sieves are used. For getting higher quality for industrial use, shakers are also required. Ther are US standard sizes for sieves, from 3 inch, 6 inch, 8 inch, 10 inch, 12 inch, and 18 inch sieves. There are also standards for metric available in the market.