A skill requirements for aluminum plate base
The basic skill requirement for the manufacture of the PS plate of the aluminum plate base is that the appearance is smooth and flat, without scratches, pits, marks, non-golden press-in, air holes, rolling strips and other apparent defects, the thickness is uniform, and the wave level is controlled. Within 1mm, the straightness is less than 2I; the structure is fine and uniform, no segregation, slag inclusion, the internal stress is divided into symmetry and uniformity; the roughness Ra value is less than 0.28, to ensure the fine and uniform electrolysis sand. At present, many of the plate-based materials used in China are 1050A, 1060 and so on.
B alkaline washing
Generally, the aluminum plate supplied by the aluminum processing plant has a certain amount of oil on the outside, and the oil and the oxide film have an influence on the disposal of the sand. In the production of the PS plate, the hot alkali is used to wash the aluminum plate for external treatment.
The alkali solution is generally used to remove the oxide film and the oil. The ratio of common degreasing liquid is: corrosion inhibitor such as sodium NaOH, and external surfactant such as sodium gluconate, fatty acid polyoxyethylene ether solubilization and complexation.
In addition to the temperature of the oil is generally controlled at about 55 ~ 60 ° C, the effect of degreasing is related to the temperature of the solution. If the temperature is too high, the people will be seriously corroded by the aluminum plate base, so it is necessary to control the temperature.
It is necessary to determine the timing of degreasing by carefully comparing the comparison. Because it is related to a variety of different production lines. The reel production line is related to the speed of the production line. Take 4m/min as an example. It is necessary to remove this oil to 20s at the time of degreasing.
In addition to the oil, it is necessary to pay attention to timely update. Since many saponifications, emulsions and aluminum salts are formed during the degreasing process, their presence affects the degreasing effect and prevents the saponification and emulsification of the oil on the aluminum surface. When the oil is not strong, it is necessary to update it in time. Generally, when the circulation is performed by the alkali pump, the degreasing liquid can persist for a long time, and if it is not circulated, the update time is shortened.
A simpler way to view the degreasing effect is to use water. The surface water of the aluminum plate with good degreasing effect can be evenly attached and scattered. If the water is poured, the surface of the aluminum plate is water-like, which indicates that the degreasing effect is not good. The temperature of the degreasing should be kept in mind. If the temperature of the degreasing liquid is too low, it can constitute incomplete degreasing.
In the production process, after the alkali washing, there is a nitric acid pickling process, the purpose of which is to remove the residual substance after the alkali washing and neutralize the remaining alkali liquid. The mass concentration of the nitric acid solution is 5% to 10%. When preparing, carefully dilute the nitric acid into the water and mix well. In the process of pickling, the concentration of the solution should be carefully observed and compensated in time.
The roughening is to form a sand structure with a desired roughness. The roughening can not only improve the affinity of the aluminum plate base for water, but also improve the surface wetting amount of the plate base to avoid the dirty surface; the roughened appearance can also improve the adhesion of the plate to the sensitizer, thereby improving the printing durability of the plate. force.
The roughened sand is composed of numerous peaks and valleys. Different sand structure has a great influence on the adhesion of the water-repellent photosensitive layer and has a great influence on the application of the PS plate. Characterized by the characteristic parameters of the rough contour profile of the sand surface produced by the top surface roughness tester.