Knife filament is a common problem of gravure manufacturers at home and abroad, and has always been the main reason that affects the yield of products. Of course, not only is the knife filament caused by the blade itself, but also the ink environment and the quality of the surface of the plate roller of.
However, in printing, the printer often changes from using a new knife to replacing it. The knife pressure always changes from small to earth. When the wire appears, it is often solved by cleaning the plate roller, blade and increasing the pressure of the blade. problem. But doing so may cause the life of the blade and plate roller to decrease, and the yield rate will also decrease.
Because we have already mentioned that the problems that occur in printing such as knife wire are caused by a variety of factors, and we cannot simply adjust the knife as the main solution. We can also solve the problem by stripping the plate roller, considering the ink, adjusting the drying path of the ink, the speed of solvent evaporation, and the viscosity of the ink.
After the problem occurs, the content involved is more complicated, and we can use the elimination method to solve it one by one, but the problem is that we need to minimize factors such as operation.
We are only here to explain the possible problems caused by the blade itself, for everyone to refer to in production.
First, the blade wire caused by the blade itself is often caused by the flat angle of our blade, so it is necessary to increase the pressure of the blade to sufficiently resist the resistance mainly from the ink. The increased contact area between the blade and the plate roller will generate greater heat, and the blade will wear easily.
When the pressure of the blade is too high, the problem can be temporarily overcome in a short time, but then the problem will reappear. Sometimes it is as thin as hair, sometimes as thick as steel wire, and in severe cases, the edge of the blade may even crack down section by section. This is mainly because the front end of the cutting edge is raised when the blade is over-pressed. As shown in figure (a).
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I have to pressurize because of the flat angle. Click here to see all news pictures
Figure (1)
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Second, when we are in the process of printing from a small pressure to the earth, the blade and the printing plate will appear as shown in (b).
In the case where the plate pressure is continuously increased, the Cr layer on the surface is constantly worn, and finally the plate roll has to be stripped after the Cu is exposed on the surface.
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Due to the need to increase the pressure when the angle is flat, there is a gap between the blade and the plate roller contact portion, resulting in the generation of wire. The pressure increased to make it smooth, but after a long time, the problem came back again ???
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Third, when we reduce all operating factors as much as possible, we can roughly summarize some methods to solve the problems that occur in printing. E.g:
1 . When a small wire appears, it is often caused by the angle and pressure of the blade itself.
2 . When a thick hairline appears, it is often caused by ink particles. At the same time, it is often accompanied by rapid wear of the doctor blade in the printed part. (Eg ink containing titanium dioxide)
3. When a group of very thick filaments appears, it is often caused by the viscosity of the ink. [next]
But the premise of the above content is: the setting of the blade installation, angle and pressure must be correct, as shown in figure (3).
Blade angle: 60 ° plus or minus 5 °
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Correct tool loading method Correct tool feeding method diagram (3)
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In general, the problems in printing are not limited to these simple problems, such as the most common phenomenon of "fogging", that is, dirty plates in non-printing parts. Operators often increase the pressure of the MDC ink scraper or adjust the blade angle slightly. Although it is easy to solve this type of problem, new problems have appeared, such as the occurrence of dots, wire lifting, etc., especially when starting the sample. When confirming the color.
In fact, at this time, we can also use new types of special coating squeegee blades and adjust the viscosity and dryness of ink to solve this problem.
Of course, the printing house is not a laboratory, and it is impossible to make a large number of new attempts. But when you are using pressure to solve the problem as quickly as possible, it is at the expense of faster blade and plate roller wear. In the process of continuously increasing the pressure of the blade, the problem will continue to appear for a long time.
The printer is a magician, he can solve the problem through the problem itself or other aspects, but new problems will appear. This promotes the development of printing technology and society.
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