What are the common problems of aluminum profile shells during the anodizing process?
During the anodizing process of aluminum profile shells, common problems mainly include:
Aluminum salt precipitation: White precipitation appears on the anodic oxide film, which is usually due to the high chloride ions in the sulfuric acid oxidation tank solution or the saturation of aluminum salts. To control the aluminum ion content, an aluminum ion content of less than 20g/L should be used.
Film peeling: The anodic oxide film is peeled off, and the anodic oxidation process suddenly stops. It is necessary to check the oxidation process and troubleshoot.
The film turns green: After sealing with nickel salts, the anodic oxide film appears light green. Sometimes when exposed to the atmosphere, excessive nickel is absorbed in the micropores. The nickel ions or pH value of the solution in the sealing groove is too high. The nickel ions and pH value of the solution in the sealing groove need to be adjusted.
Yellowing of the film: The anodic oxide film appears yellow, causing a change in color tone. This might be due to impurities such as iron and silicon in the electrolyte or alloy being mixed into the oxide film. Low anodic oxidation temperature or high current density.
Insufficient film thickness: The expected film thickness was not achieved, which might be due to incorrect calculation of the suspended area. Poor electrical contact; Constant pressure anodic oxidation. Change to constant current anodic oxidation; Check the hanging area; Check the electrical contacts.
Reduced film hardness (soft film) : The hardness or wear resistance of the anodized film decreases, and hard anodizing is more common. It might be due to the high temperature of the plating solution or the high concentration of sulfuric acid; Insufficient circulation or stirring of the liquid in the tank. It is necessary to lower the tank temperature and enhance the stirring.
Uneven film thickness: It may be caused by reasons such as uneven current distribution and poor contact between the workpiece and the electrode.
Insufficient hardness of the film layer: This may be related to improper setting of oxidation process parameters, issues with the composition of the electrolyte, etc.
Spots or flaws on the surface: This may be due to incomplete pretreatment, electrolyte contamination, etc.
Poor adhesion of the oxide film: The reasons may include problems with the aluminum material, poor pretreatment or inappropriate oxidation process.
Uneven dyeing: It may be caused by improper control of dyeing conditions or inconsistent surface conditions of the workpiece.
To solve these problems, it is necessary to strictly control process conditions, ensure the quality of pretreatment, and regularly maintain and test equipment and electrolytes, etc.