Conformal coatings are used by manufacturing companies to protect sensitive elements. This coating provides a protective chemical or polymer coating that will conform to the topology of a circuit board. The goal is to protect the electronic circuits from harsh environments that could contain chemical contaminants or moisture. Since they are electrically insulating, the coating can maintain longer-term surface insulation resistance levels. This helps to ensure the ongoing operational integrity of the item in question.
It also works to create a barrier to any air-borne contaminants that may be in the operating environment. This includes things like salt-spray, which will minimize the likelihood of corrosion.
Thanks to the protective nature of a conformal coating, it also means that they will not only provide the protection needed. They will also serve to help enhance overall product reliability, reducing the cost and the potentially damaging effects that could occur because of earlier field failures.
Understanding How the Conformal Coatings Really Work
As mentioned above, conformal coatings are types of protective barriers that provide a shield for all types of sensitive electronic components. The coating is designed to ensure that harsh environmental factors, such as debris, chemicals, and moisture, cannot negatively impact the surface being protected. Keep in mind, though, this coating is not used as a complete sealant. It is a breathable layer that protects against the environment, but it also allows moisture that becomes trapped in the PCB to get out.
The Application of a Conformal Coating
To achieve the desired effects, conformal coatings need to cover the assembly completely and provide coverage on the sharp edges and all contours. It is also essential to make sure the edges of the board are covered because they do not have solder present.
The coating’s effectiveness, on some level, is influenced by the overall efficiency of the application method that is used. This will also govern the coating type that is used. There are some suppliers that provide dedicated versions of the coating that will suit different methods of application.
There are several options for conformal coating application. Dipping is used on some materials that will not cure quickly due to light, oxidation, or moisture. Another option is selective robotic coating. These include options like DIMA, PVA, or Asymtek. Each of the coating types can be used if the proper dispenser head is used. Spraying is another method. It can be done in a booth or with an aerosol can. All the coatings can be applied in this manner. Brushing is the last application method, but it is a process that requires a skilled operator.
It is necessary to think about the curing method that is determined by the coating that is selected UV light cure, oven-dry, or air dry. The liquid coating needs to be completely wet on all surfaces and to cure without leaving any type of surface defects. Understanding what to do and how it works is essential when it comes to conformal coatings and using them for any project or need.