Different processes should choose different rollers Rollers, especially mirror rolls, are an indispensable part of the plastics packaging industry, whether it is calendering, extrusion or casting. The accuracy of the surface quality of the roller and the reasonableness of the internal flow path structure and the processing accuracy will directly affect the quality of the plastic products, especially for plastic films. Therefore, providing a high quality roller is especially important for manufacturers of plastic film products. There are many types of rollers, and they all have their own special functions. According to the process, there are rolling bars, calenders, casting rolls, etc., according to the functional use, there are heating rolls, cooling rolls, take-off rolls, idlers, etc. The structure is divided into seamless steel pipe rolls, forged and centrifugal casting rolls. In short, the different processes of plastic products require different rollers. Therefore, as a roller manufacturer, in the process of manufacturing the roller, the corresponding roller should be designed and manufactured for different products and different processes to ensure that the roller is in the process. Play a normal role in the production process. Regardless of the process, the structure, design, material selection and processing of the rolls should meet the following basic requirements: 1. The rollers should be sufficiently rigid to ensure that the bending deformation does not exceed the allowable value under heavy loads. 2. The surface of the roller should have sufficient hardness, generally required to reach more than 50 degrees HRC, and has strong corrosion resistance. The coating has anti-flaking ability to ensure that the working surface of the roller has good wear resistance and corrosion resistance. 3. The working surface of the roller should be finely machined to ensure dimensional accuracy and surface roughness. The roughness should be above Ra 0.16, and there should be no pores or grooves. The wall thickness of the working surface of the roller should be uniform, otherwise the temperature of the roller surface will be uneven, which will affect the quality of the product. 4. The material of the roller should have good thermal conductivity. Usually, chilled cast iron is used. In special cases, cast steel or molybdenum-chromium alloy steel can be used to achieve rapid and uniform heating or cooling. 5. The roller design is easy to process and the cost is low. Special requirements for rolls in the production of film products In the rolling and extrusion process, the roller usually receives a large pressing force, and a certain separation force is generated with respect to the product, so that the roller is like a cylindrical beam supported on the bearings at both ends, so the general beam cannot be used. The bending theory formula calculates the deformation, but uses the formula of the total deflection (including bending deflection and shear deflection) to find the maximum deformation. In actual production, it is proved that the total deflection in the middle of the roller is far greater than the allowable tolerance of the product, so it is necessary to try to compensate, otherwise the accuracy of the product cannot be met. Since the deflection is the largest in the middle of the roller and the two ends are small, the product is thick in the middle and thin at both ends. Therefore, there are usually three methods for the deflection compensation, namely the medium height method, the preload method and the preload device. In order to eliminate the case where the thickness of both sides of the product is thin, the working surface of the roller is intentionally processed into a waist drum shape having a large central diameter and a small diameter at both ends, and the difference between the maximum diameter of the middle portion and the minimum diameter of both ends is called the medium height E. Of course, the most ideal mid-height curve shape should be the deflection curve of the roller. However, because machining is difficult to do, it is often compensated by a part of an arc or an ellipse. In fact, the accurate mid-height curve is not necessary, because there are many factors affecting the horizontal pressure. These factors change, the transverse pressure also changes, and the deflection changes accordingly. Therefore, the limitation of the fixed medium-high compensation method. Very large, generally not used alone. Since the medium-high compensation method is simple and easy to implement, the application is more common. When the roller is no longer matched by other compensation methods, the height is in the range of 0.02 to 0.10 mm, and when used in combination with other compensation methods, the middle height is in the range of 0.02 to 0.06 mm. At present, when the manufacturer is making medium and high, the grinding head of the grinding machine is pulled at an angle according to the middle height requirement, and the two ends are grounded in the middle. Thus, the operation tends to form an angular peak, and the two sides are straight and have no medium-high curve. The large-scale CNC roll mill currently used by some enterprises adopts the computer automatic control console for curve movement, so that the milled roll surface is a curved shape, which can basically conform to the deflection curve and meet the requirements of plastic product production. Strictly implement the roller manufacturing process to ensure the quality of the roller At present, there are many roller manufacturers in China, but there are not many manufacturers that can provide high-quality rollers. The reason is that to do a high-quality roller must strictly implement the manufacturing process, lack of any intermediate process, on the surface can make a roller, but in the actual use process will expose serious quality problems, Affect the normal production of the manufacturer. Therefore, to do a high-quality roller, we must first strictly select the roll blank material. We should choose seamless steel pipe or forging or centrifugal casting according to different plastic products. In the production process, we should adopt corresponding rolls for different rolls. The heat treatment process such as quenching and tempering; secondly, in the process of processing, it is necessary to carry out stress relief after the welding process, and to perform surface hardening or nitriding treatment to improve the surface hardness, and must not be taken out because of high cost. Process, which seems to be invisible on the surface, but there are serious hidden dangers in the actual use of the production process, which is absolutely not allowed in the roller production. In addition, in the electroplating and surface treatment process, the thickness of the coating should be strictly ensured. In the grinding process, especially in the super-fine grinding process, the process steps should be strictly followed, and the normal steps should never be ignored. To reduce the process, otherwise it is impossible to produce a qualified roller. 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