Protecting the printed circuit board is very important because any exposure can affect vital functions. There is a need for reliable protection to ensure that the products are not exposed to any harsh factors, especially now that the demand for smaller, more compact devices is increasing. The versatility of electronic gadgets also requires manufacturers to guarantee protection for them to ensure durability, reliability, and quality performance.
Here are some factors associated with equipment damage:
3.Vibration or shock
5.Corrosion due to contaminants
Four methods that are commonly used to protect the printed circuit board:
This is the application of a thin polymeric film on the circuit board using a vacuum chamber. The protective coat prevents the leakage of currents as well as corrosion. Other materials used in this method are wax, epoxy, acrylic, polyurethane, and diluted silicone rubber solutions.
Protective coating is applied (by machine) through brushing, spraying, dipping and selective application after all components are soldered to the board.
- Brush coating is ideal for low volume production. It’s been linked to some disadvantages like formation of bubbles and low quality finish (operators cannot guarantee uniform thickness of the coating).
- Spraying application involves the use of aerosol or spray gun. It is good for low- to medium-volume production requirements. Spraying guarantees quality coating if done by trained operators. Two things need to be assured though. First, the printed circuit board should be clean and the coating material to be used must not have adhesion issues. It requires no specific place of operation because the application can be done in a spray booth or even on the bench top.
- Dipping application is a process that can be used in high-volume production of circuit boards. With this process, the coating completely penetrates the board and prevents leakages.
- Selective coating by machine entails the use of a needle, an atomized spray, and an ultrasonic valve which moves above the board to spray the coating. The rate flow and the thickness are programmed in the computer system. It is best for high-volume orders because the desired thickness application is both fast and accurate. This operation also requires a skilled person to operate the machine.
This method uses a gelatinous or liquid compound to make a case or mold for encapsulating the circuit board. It acts as barrier against mechanical and thermal factors that can damage the essential components.
This is the process of over molding with the use of thermoplastic or polyamide compound. The mold becomes the case or body of the electronic device. Macro melt application is ideal for delicate circuitry because it relies on low pressures to melt the polyamide compound and ensure that it will not be damaged.
The outer protective shell is formed within seconds because it does not require other conventional materials or additional mixing ingredients. The mold cavity is cost-effective because of its dual function as case and protection. Macro melt is also environment-friendly because it eliminates the need to dispose harmful waste products. It shows better protection as proven in water torture tests where microchip finished products are immersed in water then air-dried and wiped clean. Despite being exposed to such, the boards managed to remain perfectly functional.
The application involves the use of a case, a liquid gasket, and a lid. The process is done by applying hard enable liquid gasket through compression or adhesion.
It is very important to protect the printed circuit board because it is the core of any electronic device. Any issue, damage, or disruption it suffers can compromise the quality of its functions.