However, some factories find it troublesome and try to save man-hours. They neither cast symmetrical inclined holes nor drill symmetrical inclined holes on the roll body, but plan a groove on each of the two roll diameters, or use a car to cut the two shaft holes of the roll body. Each knife pulls a groove, which is not allowed by design, and at the same time violates the manufacturing standards for urethane-coated roller cores stipulated by the state. 'The technical requirements of cast iron coated roller cores have been clearly stipulated, and the national unified standards should be strictly implemented. Some enterprises simply pursue profits and ignore quality, so it is easy to cause shaft breakage or uneven hardness of the urethane layer. In order to improve the acceptance of the quality of the urethane roller, the balance cover at both ends of the urethane roller is disassembled, and the diameter and depth of the inclined hole are checked to know whether the processing is correct or not.