(Photo: Overmould)
What is Potting and Encapsulation?
Potting and encapsulation are the most common ways of protecting electronic components. They can help components become resistant to moisture, physical shock, harsh chemicals, thermal changes, and physical tampering. Additionally, they can be used to electrically insulate components.
In potting, a shell or a “pot”, containing a component, is filled with resin, which then becomes a part of the whole component. In encapsulation, the hardened resin and the component are separated in order to be placed in an assembly. Nevertheless, the terms “potting” and “encapsulation” are used interchangeably, to describe protecting a component by coating it in resin.
Where is Potting and Encapsulation Used?
Potting and encapsulation processes are used in any applications where electrical components need protection. This ranges from:
- Avionic equipment exposed to high physical and thermal changes.
- Transformers, generators and turbines in energy systems.
- PCBs (printed circuit boards) in mobile phones, computers, speakers and other appliances.
Major Types of Potting Compounds
Different types of potting compounds are used depending on the type of electronic protection desired. Generally, there are 3 major types of potting compounds:
Silicones
Silicone resins operate over the widest temperature range, out of all resins, and have excellent physical flexibility. They provide superb resistance to water, harsh chemicals, UV light, and ozone.
They are, however, an expensive option. Additionally, they are not suitable for applications requiring strong rigidity or high thermal cycling.
Epoxies
Epoxy resins are particularly well suited to achieve a high chemical and temperature resistance (up to 200°C). They are suitable for high-voltage applications as they provide a high dielectric strength.
They are, however, brittle at low temperatures. This can cause some problems if there are large temperature changes during the curing process.
Urethanes
Urethane resins are well suited for applications with thermal cycling and those in low-temperature environments. They are generally more flexible than epoxies, but less so than silicones.
They are, however, less resistant to harsh chemicals and high temperatures.
Other Potting Compounds
Other types of potting compounds, which are used if the applications specifically require them, include:
Heat Conductive Compounds
Heat conductive potting compounds, or thermally conductive compounds, are most suitable in applications where the components they are protecting are heat-producing. They allow thermal dissipation and prevent too much insulation of the components.
UV Curing Compounds
UV curing potting compounds provide the fastest curing solution (matter of seconds). However, they are not the most suitable for thick encapsulations or pottings, as they may not cure fully.
Hot Melts
Hot melts are thermoplastic compounds that are melted to cover a component. They are often UL rated and able to create watertight seals rapidly.
How To Pot and Encapsulate Safely
Care should be taken when potting and encapsulating to not damage the electronic components.
One such precaution is choosing a potting compound that produces little heat during curing, or is thermally conductive, when working with heat-sensitive components. Another precaution is to choose a potting compound that is flexible, or doesn’t shrink much, when working with delicate components or solder bands.
To learn more about electronic pottings and encapsulants, and which specific products to use, read our article: The $7.8 Billion Electronic Adhesives Market and Its Best Products.
