The rice mill is a piece of special equipment for inspecting the yield of rice, and it is also a necessary brown rice whitening equipment for rice quality inspection. The friction between the sand roller (or iron roller) and the brown rice grains in the grinding cavity of the rice mill machine is used to remove most or all of the chaff. Among them, the emery roller in the rice milling cavity increases the whiteness of the rice, and the iron roller increases the brightness of the rice. By controlling the amount of brown rice and milling time, the brown rice is milled into white rice with different precision.