What is the Purpose of Surface Finishes for PCB? A Summary of the Pros and Cons of Common PCB Finishes


This is just a summary article about PCB surface finishes. Workingbear has only worked on the electronic system assembly factory and has not been involved in the production process of bare PCBs. Therefore, the following insights are based on personal opinions. If you have different opinions or notices any mistakes, please feel free to comment and engage in discussion.

The main purpose of PCB surface finishes or call treatment is to protect the copper layer on the surface of PCB from direct contact with air, and prevent oxidation.It also facilitates effective soldering, whether directly or indirectly, with the solder, ensuring electrical conductively attaching electronic components.

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Clarifying the Concept of Electronic Component Soldering Strength


While organizing an article on the structural analysis of Micro-USB connectors, Workingbear came across an interesting soldering concept that he would like to discuss with everyone.

During the product development and NPI verification phase, RD often comes to me, I am a Manufacturing Process Engineer, with questions about the length of the metal shell soldering pins on Micro-USB connectors. Typically, these pins are only 0.8mm long because the thickness of mobile phone boards is usually around 0.8mm to 1.0mm only. However, our company’s PCBs have a thickness of 1.6mm.

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What is the difference between PCB and PCBA? PCB is like land with roads, but it doesn’t have buildings yet

What is the difference between PCB and PCBA? This is actually something that should be easily understood, but since someone asked, Workingbear will try explain it briefly here. If any readers notice any errors, please feel free to correct me.

Most people are probably familiar with the term “PCB,” and if you’ve read some stock-related financial articles, you’ve likely heard of it. However, if you’re not in the electronics industry, you might be less familiar with the term “PCBA,” and you might even confuse it with PCB. Although PCB and PCBA differ by only one letter, they have a significant difference in the electronics manufacturing industry.

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How to Bake PCB? Baking Conditions and Methods, Why Expired PCBs Need to Be Baked Before SMT or Reflow Soldering?


For many engineers, they may not understand why PCBs must be baked before going through the SMT reflow oven if they have expired their storage shelf life. Or perhaps, they believe that PCBs should be baked regardless of whether or not they have expired. But do you know why PCBs need to be baked after they have expired? And what are the limitations of PCB baking?

The main purpose of PCB baking is to remove moisture and humidity, which may be contained within the PCB or absorbed from the external environment. Because some materials used in PCBs are susceptible to the formation of water molecules. Additionally, PCBs that have been produced and stored for a certain period may absorb moisture from the environment. “Water” is one of the main culprits of PCB delamination or popcorn, and it also contributes to oxidation.

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Differences, advantages, disadvantages, and recommendations for SMD and NSMD pad designs

Do you know what are the SMD (Solder Mask Defined) and NSMD (Non-Solder Mask Defined) land pattern pads? Any difference between SMD and NSMD pads? What are the advantages and disadvantages for them? What are the design recommendations for them?

Many people in the electronics industry may have heard of “SMD (Surface Mount Device)” of  electronic components” and “SMT (Surface Mount Technology)” of soldering technology, but may not know what NSMD is. In fact, SMD and NSMD referred to here are the exposed copper pads or land pattern layout design seen on the PCB. This kind of small detail in PCB pad design was not even noticed by anyone in the past, but has become increasingly important due to the trend of electronic components becoming smaller. Because it affects the quality of solder and the strength of soldering.

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