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1. Principle: The thickness of each metal during electroplating is related to the current density and the plating time. Method: First, the area of each workpiece must be calculated, and then the current density for each workpiece is determined based on the requirements of the electroplating process. For example, the area of BYD’s Plug RF Port is approximately 0.13 dm2, and the tin-plating process requires a current density of 1.5 A/dm2; therefore, the plating current for each workpiece is about 0.20 A. If 72 pieces are hung per rack, the plating current per rack should be 15A. Once the current is determined, the thickness depends only on time. According to electrochemical calculations, when the current density is 1.5 A/dm2, it takes about 1.5 minutes to deposit a tin coating of 1 u; if a coating thickness of 4 u is desired, then 4.5 minutes are required. 2. The thickness mentioned in point 1 is the average thickness of the coating; due to the uneven surface of the workpiece, the current density varies in different areas, which results in varying thicknesses in those areas. The more complex the workpiece, the greater the difference in thicknesses. The main methods to reduce the thickness difference are as follows: A. Adding additives to the plating solution that can reduce the thickness difference ； B. Use as low a current as possible for electroplating ； Cathode movement is employed ； C. Adopt appropriate shielding measures in the high-current areas of the workpiece, etc. 3. Plug copper layer: The properties of the alloy substrate make it unsuitable for copper plating at the bottom layer. After secondary zinc plating, the surface of aluminum alloy consists of metallic zinc with high reactivity; if copper, which has lower reactivity, is used for plating, a displacement reaction will occur, severely affecting the adhesion of the coating and its appearance. Therefore, nickel plating is usually done directly; if copper is plated on top of nickel, it will affect the adhesion strength, and it also doesn’t provide much benefit for salt spray testing, so there’s no need for it. Your technical requirement is a copper thickness of 0–1.27μm, which means that it is not necessary to apply a copper plating. Moreover, a copper layer of about 1u is too thin to provide any significant benefit in salt spray tests. Zhuzhou Jianghai Environmental Protection has been dedicated to the production of high-purity ammonium chloride for 16 years. If you have any questions regarding refined ammonium chloride, feel free to call our customer service hotline at 400-0733-998. We are committed to serving you wholeheartedly!