Everything You Need To Know PCB Encapsulating Adhesive

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Encapsulation in PCB manufacturing entails the application of a compound on the electronic assemblies so as to protect them from various risk factors such as physical vibrations, moisture, dirt, dust, and any other unwanted material.

An encapsulating adhesive is a compound that has the desired physical and chemical properties to be used as an encapsulating material for printed circuit boards. It is different from conformal coating on the PCB.

In this article, we are going to discuss all you should know about PCB encapsulating adhesive and what it does in protecting PCB from various forms of external threats. If you are in the PCB manufacturing and assembling business, you will learn the best tips for choosing the right PCB encapsulating adhesive.

Overview of PCB encapsulation

There are various ways of protecting PCB from different types of risks and threats. Encapsulation is one of these ways and it is sometimes known as PCB potting. Just as the name suggests, this method entails covering the whole PCB and not just coating the surface of the board as we discussed in the conformal coating.

With encapsulation, the pot or encase will be designed and put over the whole board to provide the required protection. After putting the case, a fluid will be poured over it to act as a seal.

An encapsulating adhesive material is used in a wide range of industrial applications. It has numerous desirable properties that make it ideal for PCB applications.  The ability to flow easily coupled with excellent viscosity means that it can be easily embedded between electronic components on the printed circuit board.

Once an encapsulating adhesive cures and dries up, it will form a rubber-like material. We know that rubber materials are quite reliable in offering high-impact resistance. Your PCB will not break easily or get damaged when subjected to external mechanical forces. The rubber-like material will also have incredible heat, moisture, and chemical resistance properties.

Functions of encapsulating adhesive

The general function of encapsulating adhesive is to protect the printed circuit board and its electronic components. Let’s look at some of these functions in detail and how this type of encapsulation works to achieve them.

• Chemical protection: PCB encapsulating adhesive protects the printed circuit board from various toxic chemicals that are likely to cause severe damage to the PCB.  This role is quite useful especially when you are using PCB in a toxic application such as chemical processing.
• Protect mechanical elements of a PCB: encapsulating adhesive shields critical mechanical components of a printed circuit board such as wires and routing components from the impacts of external forces such as vibrations. By doing so, they ensure that the transmission of signals in the PCB is not affected.
• Enhance adaptability of a PCB: By covering the PCB, encapsulating adhesive makes it possible for the printed circuit boards to be used in different environmental conditions. For example, it ensures that the PCB is adaptable to both cold and hot temperatures.
• EMI and RFI protection: The thick adhesive layer that encapsulates the PCB is capable of providing protection against the impact of electromagnetic interference as well as radio frequency interference.  The end result is an uninterrupted flow of the electric signals.
• UV protection: If the PCB is to be used in an outdoor environment, you can be sure that its components will be exposed to ultraviolet radiation which can cause serious damage to the PCB. An easy way of shielding your PCB is by using encapsulating adhesive.
• Quality and compliance: Some regulations require PCB manufacturers to use encapsulating adhesives on their products. Implementing this aspect of manufacturing will ensure that you have complied with the RoHS, among other regulatory bodies.
• Reliability and performance: The overall impact of using PCB encapsulating adhesive is improved performance and reliability of the PCB module.  Protection from all unwanted elements means that the module will perform well as expected without any interference. It also implies that it will serve its purpose for a long duration without breaking down.

Factors to consider when choosing PCB encapsulating adhesive

Before you select a PCB encapsulating adhesive, you should consider the following;

• Conditions for applications: Will you use the PCB in hot or cold conditions? Will it be an indoor or outdoor setup? You should also establish the presence of toxic chemicals around.
• Adhesive potting process: How do you intend to apply the adhesive?  Will you do it manually or automatically?
• Chemicals used: Find out the ingredients that make up the PCB encapsulating adhesive. Some may end up affecting the structure and performance of electronics.
• Cost: How much are you ready to spend on the PCB?

What are the limitations of PCB encapsulating adhesive

Despite the numerous roles and benefits, there are a few demerits that are associated with the use of PCB encapsulating adhesive.

First, it may be difficult to repair the PCB or rework on it once the encapsulating adhesive has been installed. A simple task such as soldering the components may prove to be challenging. All these difficulties could be because the process of removing the coating may be challenging.

Another demerit is some encapsulating adhesive compounds may affect the performance of the PCB. This mainly originates from the dielectric properties of the coating compound. It can introduce unwanted resistance to the components of the PCB hence affecting the flow of electric signals.

While most encapsulating adhesives are designed to offer thermal shielding, others may impede the thermal management in the printed circuit board. They may reduce the maximum dissipation of heat from the printed circuit board, a factor that will directly affect the overall performance of a PCB module.

Conclusion

One of your goals as a PCB manufacturer or assembler is to build quality, durable, and reliable PCB modules. Encapsulating adhesive is one of the effective techniques that you can use to achieve this goal. The fool-proof protection that encapsulation provides will guarantee your PCB performance and reliability.

Even as you focus on using encapsulating adhesive on your printed circuits, you should also spare effort to focus on the quality of electronic components for PCB. A combination of protection and the use of premium components will guarantee the best performance. Ensure that you source these components from reputable suppliers and sourcing agents.

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