Diamond powder particle size classification

At present, many industrial technology departments require the use of 0-4m diamond powder. The particle size classification of diamond powder is getting finer and finer, and the size range is getting narrower. For 4m grade diamond fine powder, the American National Standard Ansib 74.20-1981 formulated in 1981 stipulates that 4m grade diamond fine powder has only 0~1, 0~2 and 2 ~4 Three levels.