PCB Plating: Purpose, Types, and Techniques Explained

Mar 22,2022

The PCBs contribute to the functioning of electronic devices. Thus, they need to be protected from oxidation and damage. The PCB plating is a metal deposition process that assures the protection of these PCBs from oxidation and deterioration. In addition, PCB plating provides clear surface finishing and provides an accurate soldering surface for assembling components. There are different types of plating methods for PCB manufacturing. Are you intrigued to know what they are? If yes, then this post introduces you to the same and also helps you in understanding why plating the printed circuit boards is important.

Purpose of Plating PCB

Plating a printed circuit board is beneficial for the following reasons.

• The plating helps improve the aesthetic appeal of the PCB.

• It protects the board from oxidation, moisture, and contamination.

• The PCB plating helps in reducing the overall cost of printed circuit boards and minimizes downtime.

• The plating produces clean and attractive soldering.

PCB Plating Process Discussed in Brief

The PCB plating process proceeds in the following way.

• The first step is the electroless process through which a thin copper layer is deposited on the surface area of the board, as well as the interior of drilled holes. The holes already drilled onto the board are cleaned for residues and contaminants generated during the drilling.

• The interior portion of the hole is prepared with a micro etching, which helps improve the copper binding.

• The photoresist material is added to the bottom and top of the board and exposed to UV light. This UV exposure is limited to free areas which have no patterns.

• Next, the photoresist is washed off, and the board areas are masked by the photoresist, which is hardened.

• The board is connected to the cathode of an electrical current and immersed for plating in a chemical bath.

• Dissolved copper is drawn to the negative charge and deposited on the exposed circuitry.

• The board is next dipped into the cleaning and plating baths to produce an even copper layer.

• After this, the tin is plated on the copper to protect the circuitry.

• Next, non-circuitry copper and photoresist are removed.

• Tin is removed in the final step, and the copper circuitry remains.

4 Types of PCB Plating Methods for PCB Manufacturing

There are four main types of PCB plating methods, and they are described as below:

• Through-Hole Plating:

  Through-hole plating is mainly used for the drilling process. This method uses electroless copper plating, which makes the inner walls of holes conducive to connecting the printed circuit boards easily.

• Brush Plating/Selective Plating:

  This is a portable method of electroplating the printed circuit boards. This plating method is widely used for applying electro-plated deposits and anodized coating on the printed circuit boards. No immersion tanks are used in this process.

• Finger-plated Plating:

  Finger-plating technique is often known as protruding partial plating, where rare metals are plated on the edge connectors, gold fingers, or edge joints of the board. The rare metals help improve the abrasive resistance and minimize contact resistance of the board.

• Reel Linkage Selective Plating:

  Reel linkage selective plating is a reel to reel plating method, allowing selective deposition of metals on components such as transistors, integrated circuits, and connectors.

Understanding these types of plating methods for PCB manufacturing will help you make informed decisions. However, that is not enough. To take advantage of these methods, you need to partner with trusted manufacturers like Creative Hi-Tech. Located in Illinois, the company has been delivering PCBs to its clients in aerospace and satellite, medical, military, wireless, and other industries for several years now. Thus, it perfectly understands the operating environments of PCBs and their plating requirements. The experts at the company will guide you through the suitable plating material and offer you benefits of the same.

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