The devil is in the details-Electroplating

The devil is in the details-Electroplating
Costs, the unseen expenses

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Figure 1. Electroplate Liquid

   Why is there such a big gap in quotations between PCB manufacturers for the same PCB? Even if they come from PCB manufacturers that are located close to each other, the gap can over 20%! What makes such a big difference? Actually, the PCB process is highly sophisticated, and the sum of cost differences from each station of different PCB manufacturers may lead to a gap in selling prices. Today, let us discuss the electroplating process.

     As the key to product stability, electroplating places a very important in PCB manufacturing. Simply speaking, electroplating means coating the PCB surface with a copper layer by soaking the materials in a copper sulfate liquid tank and anode bag and electrically charging the liquid. An even and ideal copper thickness is achieved by adjusting the liquid intensity, the electroplating temperature and time, and the electric current. Good copper sulfate liquid looks azure. In the process, as it is evitable that a tiny amount of impurities or chemicals from the previous tank will be deposited on the PCB surface, organic and inorganic matters will gradually accumulate in the copper sulfate liquid. After accumulating to a specific volume, these impurities will turn the azure copper sulfate liquid green or even dark green. At this time, the quality of the copper sulfate liquid is extremely low. A filter is needed to filter the copper sulfate liquid. Additionally, to maintain the quality of the copper sulfate liquid, it is necessary to replace the filter according to the production volume and actual liquid condition. To ensure fine and even surface coating, regular strong and weak electrolysis and anode bag replacement are also required.

     These quality maintenance procedures – whether it’s tank or liquid maintenance, regular filter and anode bag replacement, or the selection of consumable quality – all require considerable labor and resources. Although the absence of strict and regular treatment may not bring much trouble to low-level PCB products, it will cause various reliability problems to advanced products. For example, coarse copper particles can easily cause short circuiting, and too many impurities in the liquid easily reduce the copper ductility and lead to via cracks.  

Figure 2. The electroplate liquid has deteriorated and turned green color.
Figure 3. The electroplate liquid has deteriorated and turned green color.

  You get what you pay for! Although active charcoal filters have a better effect than PP filters, the former costs 10 times more. Polishing agent wearing and liquid intensity adjustment and replacement, cleaning and maintenance of titanium anode baskets, phosphorus copper anodes, and anode bags… These are all details that clients will never see, but they are essential to overall PCB reliability. Although decent PCB manufacturers will carry out regular checks and replacements, shops that increase profit by cutting costs will not make replacements until quality anomalies are detected.

  PCB OEMs not only stress competitive prices. Product quality and reliability must be maintained while pursuing reasonable profit so as to not let shoddy workmanship jeopardize the professionalism of OEMs. When you visit a PCB manufacturer next time, why not check out the color and filter of the copper sulfate liquid and ask for the QC SOP of the electroplating liquid? Maybe you will find out more about the big price gap in quotations!

Figure 4. Filter
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