Pad machine – a method to improve the uniformity of the pad
There are many factors that affect the uniformity of the rolling solution, such as rolling pressure, roll surface hardness and roll stiffness. The stiffness of the roll is the main structural factor that affects the uniformity of the rolling fluid. Therefore, improving the roll stiffness is the fundamental measure to improve the uniformity of the rolling fluid. However, this will cause the entire rolling car structure to be bulky, increase energy consumption and make transportation and installation difficult. Considering the structure of the roll, it is possible to reduce the deflection of the roll without excessively increasing its cross-section to improve the uniformity of the rolling fluid. This is one of the important issues in optimizing roll design. At present, the commonly used ones are medium and high rollers, medium branch rollers and medium solid rollers.
Due to general Both ends of the roll are subject to concentrated loads, and the roll body is subject to uniform loads, which is prone to bending deformation. This kind of bending deformation causes the linear pressure between the rolls to form a small distribution in the middle and large ends, resulting in uneven rolling liquid. Figure 3-19(a) is a schematic diagram of medium and high rollers. The roller body of this kind of roller is made into an olive shape with a large center and small ends. Since the diameter of the roller body is larger in the middle than at both ends, the pressure in the middle line is forced to increase while the line pressure at both ends decreases. If the middle correction value is chosen appropriately so that it is the same as the deflection value of the bending deformation of the roll after pressure is applied, that is, the working surface of the roll body can be evenly contacted, the contact line of the rolling point is completely consistent, and the effect of uniform rolling liquid can be achieved, as shown in Figure 3- As shown in 19(b). In actual production, the pressure of the rolling mill often changes due to changes in process conditions. However, this kind of roller has a simple structure and is easy to manufacture, so it is commonly used in printing and dyeing factories.
Figure 3-20 is a schematic structural diagram of the middle roll. The fulcrum of the roller body moves inward, which is equivalent to reducing the span of the beam. Under the same load conditions, the deflection is reduced, that is, the unevenness of the rolling liquid is reduced.
Will roll The body is simplified into a simply supported beam, and its stress state is shown in Figure 3-21. The deflection only decreases but does not disappear. Therefore, the problem of the uniformity of the liquid in the entire weft direction has not been solved. However, if the middle deflection of the roll and the deflection at both ends can be equalized, the color difference between the medium and shallow sides and the deep side can be solved. Through calculation, it can be seen that the deflection of the roll has been greatly reduced at this time, and its maximum value is only 20% of that of a general roll. Therefore, it has a certain effect on improving the uniformity of the rolling liquid. Suppose the length of the roller body is l, then the inward movement of the two points of the roller body at this time is:
Figure 3-22 is a schematic structural diagram of the Zhonggu roll. Only the middle section of its roller body is tightly connected to the roller shaft. Compared with ordinary rollers, the maximum deflection of Zhonggu rollers is only 1/3 to 1/4 of ordinary rollers, which has a certain effect on improving the uniformity of the rolling liquid.
Worth a visit It should be mentioned that the cleaning and assembly requirements of the middle branch roll and the medium solid roll are relatively high, and they only improve the uniformity of the rolling liquid to a certain extent.
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