Causes and analysis of the most popular flat offse

2022-07-27
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The cause and analysis of the "dead car" fault of offset press modern offset press, whether low-speed or high-speed, uses the paper feeding system and adopts the overlapping paper feeding. Therefore, during the printing operation, due to improper adjustment of the paper feeding system, or various reasons such as materials, processes, technologies, etc., multiple sheets of paper enter between the rollers, sometimes even dozens of sheets of paper, resulting in sudden shutdown. This phenomenon is usually referred to as "clunky car". The main reasons are as follows:

1. improper adjustment of the paper feeding system: the paper stack surface is higher than the front paper stop tooth, and multiple sheets of paper enter the drum

2. the air volume of the blowing suction nozzle of the loose paper is small, and several sheets of paper in front of the paper stack are completely blown away, causing multiple sheets of paper to enter the drum through the paper feeding suction nozzle

3. the thick ink layer of printed matter causes paper adhesion, and the paper is not completely loosened and twisted before being put on the machine and is input into the drum

4. the double sheet controller is improperly adjusted or fails. When multiple sheets of paper are input, if the signal cannot be effectively sent to interrupt the paper feeding, multiple sheets of paper will enter the drum

5. the front gauge electric tooth piece is out of order. When the paper feeder is improperly adjusted, the paper feeding will be skewed, causing the printing sheets to overlap and stick to the blanket. When the overlap reaches a certain thickness, the "boring" fault will occur

6. the paper feeding part falls off, or there are other sundries in the regular parts entering the drum, which causes the machine to overload and cause the "stuck" fault. Under normal circumstances, the two-color machine causes the "dead car" fault. That is, when the number of paper entering the drum is large, "dead car" mostly occurs between the first group of rubber drum and the embossing drum. If the number of paper entering the drum is small, it may occur when the first and second groups of rubber drum are under pressure at the same time due to various reasons such as mechanical speed inertia force

to sum up, the main reason for "dead running" is that the machine is suddenly subjected to a large external force during operation, which makes the machine overloaded. If it is not handled and eliminated in time, it will cause varying degrees of harm to the machine. Therefore, the pressure should be removed as soon as possible after the "dead running" occurs, The full name of the project is plasticpackagingrecyclingusingintelligentseparationtechnologiesformaterials (PRISM). In order to reduce the deformation of the drum shaft diameter and the loss of the blanket, as multiple sheets of paper enter the drum, the elastic blanket will produce large bumps in the front and back of the pressure area, which will increase the resistance of both the positive and negative rotation of the drum, making it very difficult for the paper to leave the drum. In this case, effective measures can be taken to solve the problem according to the number of paper entering the drum and the position of "stuck car":

1. turn the car manually with the turning roll. After "stuffy turning", the positive and negative inching mechanical method is adopted. When the paper cannot be separated from the pressure state, the turning roller can be used for manual turning to force the paper out of the drum with the help of external force

2. manual release pressure. When the paper cannot be pulled out of the drum by manual turning after "blocking", a wrench can be used to turn the hexagon screw on the clutch shaft head of the rubber drum operating surface, and the rubber drum can be released from the pressure by manual pressure release

3. increase the center distance of the drum to reduce the pressure. When there is a large amount of paper passing, and the above method can not solve it, the center distance between the rubber drum and the embossing drum can be increased. The method is to use a wrench to turn the pressure regulator of the rubber drum to change the angle of the outer eccentric sleeve, so as to reduce the pressure and make the paper exit the drum

4. change the angle of the eccentric sleeve in the rubber drum to remove the pressure: when the number of paper fed into the drum is large, the spot market of imported iron ore is weak and downward; Weak and stable operation of domestic ore market; The billet market is becoming stronger; The coke market continues to operate steadily and well; When the rising trend of the marine market continues and the phenomenon of "stuck cars" is serious, and the pressure cannot be adjusted, the only way to reduce the pressure is to change the eccentric angle in the rubber drum with the help of external force. The method is: first remove the pull plate connected with the coaxial sleeve on both sides of the rubber drum clutch shaft, align the iron bar with the depression at the outer edge of the shaft sleeve, and knock the operating surface and the transmission surface shaft sleeve with a sledgehammer, It mainly changes the angle of the eccentric sleeve in the rubber drum with the help of external force. Allow it to relieve pressure and exit the paper

5. remove the inner eccentric sleeve of the rubber drum. If there is a large amount of paper feeding in the drum, resulting in serious "traffic jam", if the above methods still cannot be solved, the eccentric camp in the rubber drum must be removed to separate the rubber drum from the impression drum. The methods are as follows: ① pad the rubber drum with a wooden plug and plug both ends of the rubber drum. ② Remove the transmission surface gear and other parts and make marks. When removing other parts of the operating surface that affect the eccentric sleeve in the rubber drum, it must be noted that the removal must be carried out at the same time on the transmission surface and the operating surface to prevent the drum shaft diameter from deformation

in a word: in the production process, the phenomenon of "clunky car" often occurs due to the progress of science and technology. Absurd methods such as cutting the rubber blanket or burning it with fire cannot be adopted. At the same time, strengthen the inspection of raw materials before printing, the adjustment of paper feeding system, strengthen the maintenance of machinery at ordinary times, and take corresponding measures to "suit the remedy to the case to promote the imbalance of the car" as soon as possible

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