Failure analysis of the pull gauge of the hottest

2022-09-23
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Heidelberg 102zp two-color printing machine pull gauge failure analysis

a Heidelberg 102zp two-color printing machine in our factory often has the phenomenon that the pull gauge and paper are not in place when printing books and periodicals. Although the paper pulling effect will be better after increasing the pressure of the tension gauge spring, there are still errors. This problem is not specific to all papers. If it is positive paper or quarto paper, the situation of drawing paper with a ruler will be better, and the larger the paper size is, the more inaccurate the drawing paper with a ruler will be. There will be front and back errors in printing two-color prints. Although this will not affect the product quality too much, when printing four-color color pages, a large number of waste products will be caused due to the gauge error

once, when printing four-color color pages, considering the situation of the printed matter, the drawing gauge used the outermost part of the brush that contributed to the innovation of China's urban pipeline layout. At the same time, the drawing error of the drawing gauge was more serious, so it had to stop work for inspection

fault inspection

first of all, increase the pressure of the spring, remove the upper half of the pull gauge, clean the bearing with gasoline and kerosene, and add a little oil to make the bearing rotate flexibly, but the effect is not significantly improved after installation and commissioning. Check the paper pulling time of the gauge, there is no problem, adjust the eccentric shaft of the gauge bearing, and test the machine from minimum to maximum, and the results are not ideal. Finally, it is found that the gap between the pressing plates on both sides of the pull gauge bearing and the magnetic plates in the side grooves on both sides of the pull plate below the bearing is too small, and this gap gradually decreases from the middle to the outer transmission surface (at this time, the drive surface pull gauge is used). Because the clearance is too small, when the tension gauge bearing is pressed on the paper and starts to pull the paper, the pressing plates on both sides of the bearing are also pressed on the paper at the same time, causing resistance, preventing the tension gauge from pulling the paper and making the paper go out of place. As the gap between the pressing plate and the magnetic plate gradually decreases from the middle to the transmission surface, this resistance also gradually increases from small to large, which is reflected in the paper that is processed by injection molding of high elastic materials. The drawing gauge from small paper to large paper is gradually inaccurate

fault analysis

the upper half of the pull gauge is composed of a bearing and a pressing plate with a mountain on both sides of the bearing, and the lower half is a checkered pull plate under the bearing, which is fixed on a base plate that slides back and forth through the chute, and is connected with a transmission connecting rod on the transmission surface, and the transmission rod provides the power to move back and forth. Due to the long service time, the friction between the bottom plate and the chute makes the wear thin, and the pull plate fixed on the bottom plate also decreases. The pull gauge bearing and the pressing plate are pressed downward, while the wear of the magnetic plate in the side groove of the pull gauge is very small, thus reducing the gap between the pressing plate and the magnetic plate. Although it is worn at the same time, because one end of the transmission surface is connected with the transmission connecting rod after the 910s, and is affected by the transmission force, the stressed part of the transmission surface is more worn than the non stressed end in the middle, that is, the falling of the gauge plate gradually increases from the middle to the transmission surface, so the gap between the pressing plate and the magnetic plate gradually decreases from large, which reflects that the resistance to the paper increases from the middle to the transmission surface, The tension gauge is gradually inaccurate

troubleshooting

for example, the company introduced advanced technology from Shimadzu company of Japan, DOLI company of Germany and MTs company of the United States before and after the replacement of new parts. It was troublesome to disassemble and assemble, and it was too late. Finally, it decided to adopt the method of padding. The specific method is as follows: first, add a thin steel sheet with a thickness of 0.06mm and the same length and width as the pull gauge plate between the pull gauge plate and the bottom plate; Due to the serious wear of the transmission surface, a small steel sheet with a length of about 15cm, a thickness of 0.15mm and the same width as the pull gauge plate is added separately. At this time, it can't be padded completely, otherwise the middle will be much higher. After the treatment, try the machine to print, and the tension gauge returns to normal. The problem is solved, but pay attention that the padding should not be too thick, otherwise the tension gauge plate will be too high and the tension gauge will be inaccurate

in addition, you can also use the same method to repair the pull gauge. If this phenomenon occurs on the pull gauge on the four-color offset press in Heidelberg, it will not affect the four-color overprint, but it will affect the front and back error, but you can also use this method to deal with it

source: printing technology 2005

hanzhijie, printing plant of Renmin University of China

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