Analysis of the most popular offset press paperboa

2022-08-21
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Analysis of offset press board conveying (I)

1.2 board conveying

the function of board conveying is to accurately and smoothly transmit the paper delivered by Feida to the regular part. The paper is not allowed to slide relatively on the board, which is the general guiding principle for adjusting the components on the board

1. Motion analysis of paper on the board. The paper in the Feida part depends on differential pressure transmission, so what kind of transmission does the paper rely on on on the paperboard? When there is a paper feeding failure on the paper feeding board, it shows the feasibility of using nanotechnology to purify automobile exhaust. It is often necessary to check the tightness of the cloth belt and the strength of the pressing wheel. Why do you do this

when an object is placed on a smooth surface, it will be found that it is much easier to move than when it is placed on a rough surface. When a heavy object and a light object are placed on the same surface, it will be found that a heavy object is more difficult to move than a light object. From this point of view, the pressure of an object and the smoothness of its contact surface determine the difficulty of moving an object. The force that hinders the object is called friction. The transmission of paper on the paperboard actually uses the high-speed rotating friction and wear experimental machine, which is friction transmission. Friction is equal to the product of the pressure (n) on the surface of the object and the smoothness of its contact surface (friction coefficient u), that is,

F = n U

in order to make the paper not slide relatively on the paper board, there must be enough friction, so the conditions for the existence of friction must be created on the paper board

the power of the paper forward drive comes from the paper feeding belt, and the paper drives the operation of the paper pressing wheel, so the paper pressing wheel generates a friction force that prevents the paper from moving forward. Let the friction between the paper feeding cloth belt and the paper feeding board be F1 = n u (n is the pressure of the paper pressing wheel). The friction resistance of the paper pressing wheel to the paper is F2 = n U2. Other forces on the paper can be ignored, so the force on the paper is f = F1-F2 = n (u1-u2). Because the paper moves at a uniform speed on the paper board, f = 0, that is, U1 = U2. Where U1 is the sliding friction coefficient and U2 is the rolling friction coefficient. Generally, U1> U2, because the paper and the cloth belt are in the static friction stage, that is, they do not reach the maximum value F1, that is, they are always in balance with F2, so the paper will not be in the accelerated state on the paper conveyor

it can also be seen from the above analysis:

(1) The forward movement of the paper has nothing to do with the pressure of the paper pressing wheel, that is, no matter how high the pressure is, the paper will not accelerate or decelerate

(2). The function of the paper pressing wheel is to make the paper and the cloth belt have reliable contact and generate enough static friction

(3). If the surface of the cloth belt becomes very smooth, that is, U1

2. The function and adjustment of various parts on the paper board. The components on the paperboard conveyor include a paper receiving roller, a guide plate, a double sheet controller, a paper feeding cloth belt, a paper pressing wheel, a brush wheel, a paperboard conveyor, an air suction hole, and a paper pressing frame. The following is a detailed analysis of the functions of various components that need maintenance

(1). Paper receiving roller the paper receiving roller is mainly used to guide the paper passed from the paper delivery suction nozzle into the paper board. The transverse lines on the paper receiving roller play a role in increasing friction, so as to prevent relative sliding between the cloth belt and the paper receiving roller. There are two paper pressing wheels on the paper receiving roller, which are used to make the paper reliably contact with the paper receiving roller. The paper pressing time should be consistent with the paper transfer time of the paper delivery suction nozzle

(2). Guide plate the function of the guide plate is to guide the paper transferred by the paper receiving roller into the cardboard conveyor. Its flatness can be adjusted with screws

(3). Double sheet detector how many papers are there under the double sheet detector? This problem is sometimes unclear. The key problem is that we don't know what the dual detector is for. The function of the double sheet detector is to detect that there cannot be two or more sheets of paper input each time, which has nothing to do with the number of sheets of paper below. The organizing committee will arrange preferential accommodation

take 540mm wide paper as an example. Generally, the paper feeding step distance of Heidelberg printing press is 200mm (the distance between the paper feeding step distance and the mouth of two pieces of paper) is shown in the figure:

(Figure 1.10a)

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