Potting or encapsulation is a process of filling a housing with an electronic assembly with a compound that sets after curing, for resistance to shock and vibration, and for exclusion of moisture and corrosive agents. Reed Switch based Magnet Sensors with cables are potted with a flexible two component epoxy to ensure higher shock resistance.
In electronics, potting is a process of filling a complete electronic assembly with a solid or gelatinous compound for resistance to shock and vibration, and for exclusion of moisture and corrosive agents. Thermosetting plastics or silicone rubber gels are often used, though epoxy resins are also very common. Many sites recommend using a potting product to protect sensitive electronic components from impact, vibration, and loose wires.
In the potting process, an electronic assembly is placed inside a mold (i.e. the "pot") which is then filled with an insulating liquid compound that hardens, permanently protecting the assembly. The mold is part of the finished article and can provide shielding or heat dissipating functions in addition to acting as a mold. A cast assembly uses a removable mold.
As an alternative, many circuit board assembly houses coat assemblies with a layer of transparent conformal coating rather than potting. Conformal coating gives most of the benefits of potting, and is lighter and easier to inspect, test, and repair.
When potting a circuit board that uses surface-mount technology, low glass transition temperature (Tg) potting compounds such as polyurethane or silicone are used, because high Tg potting compounds may break solder bonds through solder fatigue as they harden and shrink at low temperatures.