In particular, mirror roll roller for plastic packaging industry is not prepared an important and indispensable component, whether it is rolling, extrusion or tape casting are inseparable from the rollers.
Production of quality precision roller surface and internal structure of the rational flow and processing accuracy is good or bad, will directly affect the quality of plastic products, in particular, is especially true for the plastic film. Thus providing a high quality plastic film roll film products for manufacturers is particularly important. A wide range of roller, and has its unique role, divided by process rolling stick, pressure bachelor, tape roll so divided by function and purpose of the heating roll, cooling rolls, away from the roller, roller, etc., by structure divided into seamless roller, centrifugal casting and forging roll. In short, plastic products, different processes require different roller, therefore, as a roller roller manufacturer in the production process to undertake, should be for different products, different process design and manufacture of the corresponding roller, roller in order to ensure the production process to play its normal role. Regardless of what technology means to the roller structure, design, material selection and processing should meet some essential requirements:
1. Roller should have sufficient rigidity to ensure that under heavy load, bending does not exceed the allowable value.
2. Roller surface should have sufficient hardness, the general requirements to achieve HRC50 degrees, with strong corrosion resistance. Coatings have anti-stripping ability, to ensure that the working surface of the roller has good wear resistance and corrosion resistance.
3. Roller work surface should be fine processing, in order to ensure dimensional accuracy and surface roughness. Roughness should Ra0.16 above, can not have pores or grooves. Working surface roller thickness to be uniform, otherwise it would be uneven roll surface temperature, affecting the product quality.
4. Roller material should have good thermal conductivity, usually chilled cast iron, cast steel or special circumstances with chrome molybdenum alloy steel, either heating or cooling, can achieve rapid and uniform.
5. Roller designed to facilitate the processing and low cost.
The production of film products in roll the special requirements of
In the rolling and extrusion process, usually appear under a lot of roller compaction force, the relative separation of a certain product, giving support as if the roller bearings at both ends of the cylindrical beam and therefore can not use normal beam calculated using the theory of bending deformation, but with the deflection value (including the bending deflection and shear deflection) seek the formula the maximum deformation. Proven in actual production, the total central deflection roller products allow far greater than the tolerance, it must seek compensation, or to reach the product accuracy. Since the maximum deflection in the middle of the roller, both ends of the smaller, and therefore intermediate products appear thick, thin ends of the situation, so deflection compensation approach is usually three, namely, the height method, pre-load method and pre-load devices.
In order to eliminate the middle of thick products, the situation on both sides of a thin, consciously working surface of rolls processed into a large diameter in the middle, both ends of the small diameter drum-type, in which both ends of the Ministry of the largest diameter and minimum diameter as the height difference between the E. Of course, the ideal shape of the curve in the height of the deflection roller should be the curve. But difficult to do due to mechanical processing, often used as part of circular or oval approximately be compensated.
In fact highly accurate curve is not necessary, because of the size of the horizontal stress factors, these factors change, cross-pressure changes, also change with the deflection, so the fixed limitations of highly Compensation large, generally not used alone. As the altitude compensation method is simple, more general use. When the roller with no other compensation method, one of the height range of 0.02 ~ 0.10mm, and other compensation method when used in combination, in the height range of 0.02 ~ 0.06mm. It is generally high in production factories, grinding through the grinder at an angle in high demand pull from both ends to the middle of grinding, this operation will often form a horn, on either side is flat, but not the high curve. Some businesses use a large CNC roll grinding, the use of a computer control console were curved, so grind the roll surface is a curve shape is basically consistent with the deflection curve and meet the requirements of plastic products.
Strict implementation of roller production process to ensure the quality of the roller
At present, domestic manufacturers have a lot of roll, but really high-quality roller few manufacturers. The reason is to do a high-quality roller manufacturing process must be strictly enforced, the lack of any middle of a process, can make the roller surface, but in actual use will be revealed serious quality problems, affect the normal use of factory production. Therefore, to successfully roll a high-quality selection of the first roll blank to strictly material, plastic products according to different processes to use seamless steel pipe or centrifugal casting or forging documents, in the production process, for different roll blank to use the appropriate the quenching and tempering heat treatment process; Second, in the processing process, you must also eliminate the stress after the welding process, in order to improve the surface hardness of the surface hardening or nitriding processes, must not be deprived of them because of high costs process, which seems on the surface is not apparent, but in the actual use of the production process there are serious problems, which absolutely does not allow roller production. Again, in the electroplating and surface treatment process should be rigorous to ensure that the coating thickness is moderate, particularly in the grinding process in the ultra-fine grinding process should be strictly in accordance with the process steps, should never be neglected figure Province Figure fast normal steps to reduce the process, or no legal and qualified to roll.
