Fault analysis and solution of two cases of the ho

2022-08-10
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Fault analysis and solution of two cases of grid knife hybrid folding machine

grid knife hybrid folding machine is a popular model in China at present. The machine combines the advantages of fence type and knife type folding. It adopts Feida paper feeding mechanism, with fast folding speed and high precision. Therefore, how to correctly use this kind of equipment to judge and eliminate the faults in time and accurately, so that it can give full play to the best performance of @2 and 30 seconds after power on, is of great significance to improve the production speed and product quality

next, take the zyh660 grid knife hybrid folding machine as an example to analyze and eliminate the two failures that occurred during the Iraqi tour. The photoelectric switch for reducing its speed in the paper pile is an important part of the paper pile control mechanism, which is located 25mm below the paper feeding suction wheel. Under normal circumstances, press the stack up button, and the stack will rise rapidly. When the paper stack blocks the photoelectric switch during the rising process, the paper stack will rise slowly, and Feida will also make automatic adjustment. When the paper stack rises to about 3mm from the proximity switch above it, the proximity switch m operates and the paper stack stops. At this time, after the machine is adjusted according to the paper thickness and paper, the main machine can work normally by turning on the key on the console

fault phenomenon 1

after pressing the paper pile up button, the paper pile rises rapidly. When blocking the photoelectric switch, the paper pile cannot slow down, and continues to rise in a fast way until it rises to the end limit switch above it. After the paper stack stops rising, Feida cannot make automatic adjustment, and there is no gap between the paper stack and the paper feeding suction wheel and the proximity switch. If the machine continues to operate, there will be paper tearing, paper plugging and other phenomena

analysis and solution:

from the fault phenomenon, the paper stack still does not slow down when it rises to block the photoelectric switch. There is a high possibility that there is a problem with the photoelectric switch. After lowering the paper stack and checking the photoelectric switch, we found that there was no other abnormal place except slight dust accumulation on the electric eye of the photoelectric switch. After gently wiping the electric eye with a clean and soft cloth, use your hand instead of the paper pile to block the photoelectric switch. After pressing the paper pile up button, you find that the paper pile can slow down and rise in a slow way: remove your hands, and when the rapidly rising paper pile blocks the photoelectric switch, you still can't slow down

in order to find out the reason, remove the paper stack from the cardboard lifting table, carefully observe the contact position between the surface of the paper stack and the photoelectric switch, and find that there is a black ink belt from top to bottom, that is, marking. It is used for the convenience of quality inspectors to pick out errors such as white plates during inspection. There are labels on each page. After the pages are stacked neatly, an ink band appears from top to bottom. In order to verify whether there is a problem with this ink belt, replace the paper pile without ink belt again. After pressing the paper pile rise button, the new standard of the cup burst tester of Jinan testing machine factory rises quickly. When the paper pile blocks the photoelectric switch, the paper pile can slow down, and all kinds of actions of the machine are normal. Therefore, it is judged that this black ink belt has affected the normal operation of the machine

this problem can be solved by sticking a piece of white paper in front of the photoelectric switch and letting the photoelectric signal of the photoelectric emitter hit the white paper. The paper is pasted on the window in front of the photoelectric switch with self-adhesive tape, and then the original paper with black mark is reinstalled on the paper lifting table. Press the paper pile up button, and then the paper pile rises. The difference is that the paper pile rises slowly. In addition, other actions and functions are normal. Although the method of blocking the black mark with white paper makes the speed of the rapid rise of the paper stack a little slower, it effectively solves the problem of the photoelectric switch failure of the paper stack caused by the black mark, so that Feida can't feed paper

because the paper suction body of Feida has no paper feeding action (the suction nozzle can only move up and down under the action of vacuum and spring, and cannot move back and forth), the paper can only be sent out by sucking the paper by the paper suction wheel and pulling the paper out of the suction nozzle when it rotates. In order to make the paper feeding suction wheel deliver the paper well, the paper suction body of Feida machine is specially designed, that is, there are two air inlet needle valves on the paper suction body, and there are two collision screws above the two air inlet needle valves. When the paper suction body sucks the paper through the suction m carried by it and moves upward, the two air inlet needle valves are hit by the collision screws above it, and the vacuum between the suction nozzle and the paper is destroyed after the needle valve is pressed down, The suction of the paper feeding suction wheel is greater than that of the suction nozzle, and the paper is pulled out and sent away

fault phenomenon 2

it can be seen from the working process of Feida that the upper suction nozzle of Feida has no vacuum shut-off device, and only relies on the inlet needle valve to destroy its vacuum to reduce the suction. Due to inertia, the vacuum destruction effect of the suction nozzle is the best only at the moment when the air inlet needle strikes the impact screw. However, in the process of paper feeding, due to the limitation of time (because it needs to cooperate with the folding knife on the time division), it is impossible to send the paper away at the moment when the air inlet needle valve is impacted. Before the second paper feeding action of the paper feeding suction wheel starts, the paper suction body must maintain the suction force on the paper. In this way, the air inlet needle valve on the paper suction body will always be in the semi reset state, and the destruction effect of vacuum is not ideal. If there is thick or smooth surface and pumping paper, its slip (empty sheet) phenomenon is inevitable. To avoid, only increase the suction force of the paper feeding suction wheel. The machine has just been maintained, and the vacuum pump and air circuit are free of faults, and the vacuum regulating valve of the air pump has been adjusted to the maximum (60 pump), that is, the suction force of the paper feeding suction wheel can no longer be increased. Through this method, the suction effect of the paper feeding suction wheel can no longer be improved, which is the reason for the empty phenomenon

analysis and solution:

through the observation and analysis of the paper feeding suction wheel and the paper suction body, it is found that reducing the contact area between the suction nozzle and the paper is very beneficial to avoid empty sheets. Under the condition of constant vacuum, the larger the contact area, the greater the suction. In order to enable the paper suction body to accurately suck up the paper during the paper suction process, a rubber cup is sleeved on the suction nozzle of the machine, which can avoid the air leakage phenomenon of the suction nozzle during the paper suction process. In the fields of alloy steel, superalloy, metal functional materials, refractory alloy, powder metallurgy materials, etc., but this also increases the contact area between the suction nozzle and the paper, and increases the suction force when the paper is pulled out, This makes it difficult for the paper feeding suction wheel to feed paper out. Reducing the contact area between the suction nozzle and the paper is equivalent to increasing the suction force of the paper feeding suction wheel, so that the paper feeding suction wheel can accurately send out the paper

during the paper suction process of the machine, when the air inlet needle valve is in the semi reset state, the vacuum destruction effect is not ideal, resulting in the disharmony between the paper suction body and the paper feeding suction wheel under the same vacuum. The suction force of the suction nozzle is large to realize the tightening movement of the spring, and the tension of the paper feeding suction wheel is relatively small. In case of thick paper, smooth surface or inflated paper, the suction wheel fails to pull the paper and slips (empty). This problem can be effectively solved by reducing the contact area between the suction nozzle and the paper

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