1. Alkaline etching process: It consists of degreasing→water washing→alkali etching→water washing→water washing→light extraction→water washing→water washing→oxidation, that is, after the profile is deoiled, it is treated by alkali etching in the alkali etching tank to remove mechanical lines and natural oxidation. Film, sand, and then remove the black ash on the surface through the light-emitting tank, and then the anodization can be carried out. The core process of this process is alkaline etching, and the surface flatness of the profile and the quality of sanding are all determined by this process. In order to achieve the purpose of leveling the mechanical pattern, it generally takes 12-15 minutes of alkali etching, the aluminum consumption reaches 40-50Kg/T, and the alkali consumption reaches 50Kg/T. Such high aluminum consumption not only wastes resources, but also brings serious environmental protection. problem, increasing the cost of wastewater treatment. This process has been used for more than 100 years, and it is still used by most of the world's aluminum factories. It was not until the past two years that it was gradually replaced by acid etching.
2. Acid etching process: It consists of degreasing→water washing→acid etching→water washing→water washing→alkali etching→water washing→water washing→light extraction→water washing→water washing→oxidation. After degreasing, the profiles are acid-etched first, then alkali-etched, light-emitting, and pre-treatment is completed. The core process of this process is acid etching, and the removal of mechanical lines and sanding are all determined by acid etching. Different from alkaline etching, the biggest advantage of acid etching is that it has strong ability to remove mechanical lines, fast sanding, and low aluminum consumption. Generally, it can be completed in 3-5 minutes, and the aluminum consumption is almost 1/8-1/6 of that of alkali etching. From the perspective of work efficiency and resource saving, acid etching is undoubtedly a major improvement in the alkaline etching process. However, the environmental protection problems of acid etching are more prominent: the escape of toxic gas HF from the acid tank and the pollution of the washing tank Fˉ. Fluoride is generally highly toxic and more difficult to handle. In addition, after the acid etching treatment, the appearance of the profile is black and dark. Although the alkali etching and light extraction have to be continued, it can be brightened, but it is still very dark, which not only increases the process, but also loses the gloss. solution.
3. Polishing process: It is composed of degreasing→water washing→polishing→water washing→water washing. After degreasing, the profile is put into the polishing tank. After 2-5 minutes of polishing, a mirror surface can be formed, and it can be directly oxidized after washing. The core process of this process is polishing, and the de-texture and mirror surface are all completed in the polishing groove. Polishing has the advantages of low aluminum consumption and bright profiles, but the escape of NOx from the polishing tank causes serious environmental pollution and physical injury to operators.