The metallographic scale of 250 microns represents the actual magnification.

If a short segment represents 250um, then it is 250um. Measure how much this short segment is with a meter ruler, indicating the enlarged size; Divided by 250um, it is the magnification; Units should be unified, and it is more convenient and intuitive to use mm as far as possible.

Screen inner diameter (micron) ≈ 14832.4/ screen mesh unit mesh particle size refers to the size of raw material particles, generally expressed by the maximum length of particles. Mesh refers to the mesh size of a standard screen. In Taylor's standard sieve, the so-called sieve hole is the number of sieve holes with a length of 2.54 cm (1 inch), which is simply called sieve hole. Taylor's standard screening system: The classification of Taylor's screening system is based on a 200-mesh screen hole size of 0.074 mm, which is multiplied or divided by the n power of the square root of the main module (n = 1. 14 1) to obtain a screen hole size thicker or thinner than 200. Similar to the enlargement of metallographic structure. The plus sign or minus sign in front of the grid indicates whether the grid of the grid will be lost. A negative number indicates the number of meshes that can be leaked through the number of meshes, that is, the particle size is smaller than the number of meshes; A positive number means that the grid cannot be omitted, that is, the particle size is greater than the grid size.