In the process of aluminum plate factory or application, sometimes there are black spots on it. What's the matter? The aluminum plate manufacturer will take us to analyze. One is the material of aluminum plate. The top cover of aluminum plate produced by aluminum plate manufacturer is LF21 aluminum plate with thickness of 0.5mm. The aluminum plate of the model has many kinds of the same materials, similar shapes, the same part processing process, and the same processing cycle. The parts with similar shapes have no such defects. This is not the defect of raw materials and the failure caused. Therefore, in the process of processing, the general process of silver plating on the cover is: machine tool add-on-pretreatment-electro-galvanizing-electro-copper-electro-silvering-coating-dip-823-storage.
In the process of electroplating aluminum plate, first of all, some production links of electroplating may have changed, leading to failure. However, the similar parts processed at the same time did not have such failures when the production conditions did not change. Therefore, the change of electroplating production conditions is not included. According to previous production experience, the most common reason for discoloration of silver plating is the influence of sulfur element on silver plating layer.
In the past, the parts after silver plating were not packed and sealed in time, which resulted in yellow plating layer in electroplating workshop for a long time. However, the defective parts shall be timely packed and stored in dry containers after silver plating, which shall not be affected by the air atmosphere in the workshop. In the process of painting, it is found that a batch of maintenance records have been made in the process of painting the cover. The main reason is that the gap is not blocked, allowing the paint mist to enter and adhere to the surface of the silver coating. In order to prevent this kind of failure, it is recommended to seal the gap with 3M tape during processing to prevent paint mist from entering.
Through this elimination method, we found the root cause of the problem, and we immediately took measures to eliminate the hidden dangers, so that the aluminum plate surface is bright as new, and the delivery rate is greatly increased.