The mirror roller is generally made of 45# steel, alloy steel seamless pipe, precision forging and other materials, and the mirror surface is processed on the surface, and at the same time, the straightness, balance, out-of-roundness and coaxiality of the roller surface are guaranteed to reach Requirements; the surface finish of the roller can reach Ra0.03 at the highest. The surface coating generally has two kinds of chrome plating or ceramics. The surface hardness is HRC55~62, and the thermal deformation is not more than 0.01mm.