The aluminum alloy guide roller is the main component of the reel type film material. Because of its light weight, stable transmission, simple installation, beautiful appearance and corrosion resistance, it is widely used in packaging. The printing , paper industry, film industry, textile industry, rubber industry, paper, film, film, cloth, leather, silk and other materials transmission, the market demand is large. This paper mainly discusses the problems that should be paid attention to during the selection, processing, installation and maintenance of aluminum alloy guide rolls in the packaging and printing industry .
(1) Selection of aluminum alloy guide rolls
1. Selection of installation methods
The basic structure of the aluminum alloy guide roller: the roller is the direct working part of the material transfer, and is the key part of the guide roller; the aluminum plug is directly connected with the inner wall of the roller, which is the transition part of the guide roller support; the shaft head is the support part of the guide roller , connected to other components through transmission parts such as bearings.
Aluminum alloy guide rolls for the packaging and printing industry are divided into shaftless guide rolls and shaft type guide rolls according to the installation method. A shaftless guide roller, the roller has no protruding shaft at both ends, a bearing, a half shaft is installed at the aluminum plug, and is connected with the wall plate; there is a shaft type guide roller, and both ends of the roller have an extended shaft connected with the roller body Connected to the bearing on the wall panel by the extended shaft (if it is connected to the gear, it can be pulled as part of the tension control).
2. Selection of materials
In the packaging and printing industry, the aluminum alloy guide roller is less stressed, so the material can be selected from light and easy to process aluminum. The roller body is directly subjected to the tensile force of the film. In order to prevent the bending deformation due to the self-weight of the roller, the aluminum alloy LY6005 pipe material with higher relative strength is generally selected, and 6 to 8 circles having a radius of 4 to 5 mm are evenly distributed at the pipe wall. The arc acts as a rib and its cross-sectional shape. The plug is welded with LY12 and roller body. The shaft head with the protruding part of the shaft type guide roller is selected from 45# quenched and tempered steel, and the matching method is casting with the aluminum plug, and then integrally welding with the roller body. Cross-sectional dimensions of other aluminum alloy profiles.
3. Selection of diameter
The aluminum alloy guide roller is divided into Î¦80, Î¦90, Î¦100, Î¦120, Î¦150 and other specifications according to the outer diameter of the roller. The specific specification is related to the printing tension, the wrapping angle of the film, and the like, that is, the force of the guiding roller is determined. The guide roller receives the film tension. Under the action of the same tensile force T, the outer diameter of the guide roller is different, and the wrap angle Î¸ between the tensile force and the roller is also different, and the radial uniform load q received by the roller is also different.
The formula for the radial uniform load q is
Obviously, in the case where the tension T is constant, q is proportional to the cosine of the wrap angle Î¸, and the larger Î¸ is, the smaller q is; the smaller Î¸ is, the larger q is.
Because the aluminum is soft and easy to deform, and the guiding roller is an elongated shaft, the roller body is a pipe material, which is easily deformed under external force and affects the quality of the printed matter. Therefore, when selecting the diameter of the guiding roller, it is necessary to comprehensively consider the printing material, printing speed, etc. factor. If the small-diameter roller body is selected only in consideration of the cost, the wrap angle Î¸ is small, and a large cumulative load is generated on the guide roller under the action of the film pulling force T.
Taking gravure printing as an example, the substrate is selected as a plastic film with a width of 1.5m, a speed of 180-200m/min, a printing tension T of about 15N, an outer diameter of Î¦90, a wrap angle Î¸=30Â°, and a deflection y. The amount of deformation of the roller. The calculation process is as follows.
Width: L = 1.5m
Uniform load: q=2TcosÎ¸=260N/m
Elastic modulus of aluminum: E=70GPa
Such deflection bending will result in uneven force on the film, and the overprinting is not accurate, which does not meet the requirements of gravure printing. If Î¸ is decreased, the deflection is increased and the printing quality is more affected, so Î¸ cannot be too small. Under the same circumstances, the paper tension is generally 1.5 times that of the plastic film, and the load on the guide roller is relatively large, which is more likely to cause deformation. It can be seen that when selecting the diameter of the guide roller, the strength should be comprehensively considered to reduce the bending deformation of the guide roller.
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