Anodize Enclosure Aluminum Extrusion PCB Housing Box Electronic Shell1

The heat sink shell is one of the most fundamental components in cooling electronic devices. For any heat source that cannot be properly cooled through its own conduction cooling and needs more efficient cooling than a heat spreader, a heat sink is necessary to move heat away from the source and dissipated through more optimized conduction or convection. 
Heat sinks are primarily constructed with a base and fins. The base is typically a planar surface that makes contact with the heat source and spreads the heat from the hot spot to the fins. Fins can be cut or constructed in any number of geometries which often run perpendicular to the base to disperse heat. The goal is to optimize the surface area of the heat sink so that the most heat can be transferred and dissipated.With rare exceptions, heat sinks are made of a thermally conductive metal, the most common being Aluminum. 
Aluminum has a thermal conductivity of 235 watts per Kelvin per meter and is lightweight and inexpensive, making it ideal for lighter, more cost-efficient heat sinks. Copper is also a popular choice. Although copper is more expensive and heavier, it can be necessary for high performing applications due to its high thermal conductivity at 400 W/mK.
Finally, engineers often class heat sinks into “natural” convection or “forced” convection. Natural convection (Passive) heat sinks maximize surface area and conduct heat without the addition of active components. Forced Convection (Active) heat sinks are designed to utilize components such as fans and blowers to force cooler air across the fins, creating turbulence and increasing the cooling performance of the heat sink.