How to detect and repair the failure of pressure c

2022-09-27
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How to detect and repair the failure of the pressure cylinder

for the printing machine that uses the air circuit to control the cylinder clutch pressure, the pressure cylinder is an important component. Once it is damaged, the machine will not be able to help them choose the compound method that can best meet their needs to operate normally

some time ago, the action of the third combined pressure cylinder of our Heidelberg SM74 machine was not in place, resulting in the failure of the press cylinder to close, resulting in the printing text is either lack of color or false printing (that is, the text is blurred or blurred), and the normal production cannot be carried out. Before this problem occurred, the factory replaced a new cylinder according to Heidelberg engineers. However, the service life of new parts is very short. Generally, they are damaged in about one year, and each cylinder is very expensive, nearly 20000 yuan, causing great losses to the factory

in order to save money and solve the problem, we decided to solve this fault by ourselves. According to the phenomenon analysis, it is judged that it is caused by the cylinder itself, which has nothing to do with the electrical part. Therefore, remove the cylinder and pull the piston rods on both sides by hand. It is found that there may be a problem with the piston on the side with large force and small resistance. If the piston ring is worn, replace it with a new one. The way to eliminate this kind of fault is: but it cannot be ruled out that the solenoid valve is damaged. In order to accurately judge whether the solenoid valve or the piston ring has a problem, I replaced the solenoid valve that I thought was damaged on the cylinder with a new one (that is, the technology behind is also constantly improving, that is, the solenoid valve without plug), and the phenomenon is the same as before. After changing the positions of the two solenoid valves with each other, the resistance also changed. The side with small resistance became larger and the side with large resistance became smaller. Install it on the machine, connect the air circuit, and reverse the composite pressure test. The problem has been solved. It has been used until now, and the above failure has not occurred again

therefore, it is judged that the problem lies in the two solenoid valves. Therefore, the two solenoid valves were disassembled for inspection, and it was found that the structure of the solenoid valves was a little different. One solenoid valve had a plug with a small hole at the inlet of the air path, and the other did not. Compared with the cylinder equipped with the original machine, it is found that the two solenoid valves of the original machine cylinder have a screw plug with a small hole (which regulates the gas path), and the service life of the original machine cylinder is about 4 years. However, the longest service life of the cylinder with a screw plug on the unilateral solenoid valve is 1 year, and the shortest is only a few months

through the anatomical analysis of the bad cylinder, we found that there is no screw plug on the cylinder solenoid valve, which can avoid the small hole being blocked by dirt during long-term use, so as to ensure the smooth exhaust. However, if some dust particles and oil dirt enter the cylinder, the piston ring will be worn and aged, and the electromagnetic valve core will be blocked and inflexible, which will lead to air leakage of the cylinder and cannot be used normally. In addition, there is no screw plug on the cylinder solenoid valve. Although the exhaust is unobstructed, the movement of the cylinder piston will be unstable and the sound will be very loud. In the long run, it is easy to shorten the service life of the cylinder piston ring, and it is also easy to cause damage to the external seal ring, resulting in air leakage of the cylinder

the solution is to install the same plug at the same position of the solenoid valve without adjusting plug. This can not only avoid the entry of dirt, but also ensure the smooth action of the piston. From the experimental results, in the loading process, the load not only ensures the normal use of the cylinder, but also extends the service life of the cylinder

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