Almost every electronic device manufactured uses a printed circuit board (PCB). From our smart phones to microwave ovens, you will find PCBs. The exact type of PCB varies by application: some have multiple layers, some are flexible. What most PCBs have in common is a certain way of protecting the environment.

Regarding PCB protection, there are several options. The most common is conformal coating, in which the PCB is coated so that the copper traces are usually covered by a red or green coating. Coating the PCB can prevent corrosion and prevent the solder from flowing to the wrong place when filling the circuit board. The conformal coating is first applied to the PCB to mask it to prevent the copper pads from being coated. After that, the coating is applied by various methods such as spray coating or dip coating. In some cases, a conformal coating can be applied to the board after the board is filled so that the component is also coated. This can be done when more extreme environmental protection is required (for example, in a marine environment).
Another method used to protect electronic devices is called a spherical top, which is usually used in mass manufacturing. This method can be used when placing the silicon chip directly on the PCB because it can reduce the cost of packaging the IC. To protect the original die, a layer of sealing material is placed on top. This usually appears as a black spot on the PCB.

Filling and encapsulating the circuit board involves completely covering the assembled PCB with a resin or epoxy coating, thereby completely sealing it. This method has some disadvantages and advantages. One of the benefits is that the PCB and its components are fully protected from the environment, in addition to corrosion problems, but also from shock and vibration. Filling PCB can also provide a certain degree of safety protection

Copy the design. Some encapsulating compounds are designed to be difficult to remove and opaque, so no information can be learned. If there is a dangerous voltage on the board, the safety can also be improved by potting the PCB.

Source: Sengokucannon / CC BY-SA 3.0

Some of the disadvantages of encapsulating circuit boards include increasing the weight of the potting material. If not impossible, packaging also makes repair impractical. Heat is another issue, depending on the circuit design and the compound used. Although most sealants emit heat, some special compounds contain metal oxides, which are designed to conduct heat and can reduce or eliminate heat problems.

The packaging is usually performed where high shock and vibration may cause problems such as for automobiles, ships, or aerospace vehicles.

If used correctly, these methods may be very effective. Although the methods involved and the completed methods vary, almost every PCB has some form of protection to prevent environmental problems. In some cases, the PCB can even use multiple methods, for example, a PCB with a spherical top that has a conformal coating on the board and then is packaged.