There are three possible reasons for the uneven color of the oxide film of aluminum profiles
1. The area of the workpiece is too large, the swing in the groove is too large during operation, and the contact, renewal and exchange between the edge and the center part and the solution are too different, resulting in inconsistent color of the oxide film. Prevention method: The swing of the workpiece should be small during oxidation, and static treatment is also possible, but when the temperature of the solution is too low, map-shaped spots are prone to appear, which is unnatural.
2. When the aluminum-clad parts are processed, part of the aluminum-clad layer is damaged and cut off. The outer layer of aluminum is high-quality aluminum, and the inner layer of the clad is miscellaneous aluminum. The difference between the two types of aluminum is large, so spots appear after oxidation. This phenomenon is often not understood by customers, and manufacturers should do more explanation work to explain the reason, so as not to cause misunderstandings.
3. Process operation problems
① The alkaline etching treatment of the workpiece is not thorough, and the original oxide film and dirt in the local area cannot be completely removed;
②The surface of the workpiece is still alkaline if the light-emitting treatment is not performed immediately after the alkali etching;
③ The workpiece has come into contact with foreign objects during the transfer process.
When the color of the film is not uniform, it is necessary to find the reasons from various aspects and take targeted measures to solve it.