Get rid of the heat Heat sinks for your electronic devices

Heat sinks absorb heat from an electronic component and dissipate it into the surrounding environment. To do this, they are made of a thermally conductive material, such as aluminium or copper, and have a large surface area, for example in the form of fins or lamellae. Applying TIM (Thermal Interface Material) reduces surface irregularities between the heat sink and the component surface and significantly improves the thermal resistance. When combined with a fan, the cooling performance is further enhanced.

The most common material used for heat sinks is aluminium. It has a thermal conductivity of approximately 210 W/mK, is very light with a density of 2.7 g/cm³, and is available at a reasonable price. Aluminium is typically used as an extruded or die-cast alloy – in some cases (particularly for cold-formed LED heat sinks) it is also used as pure aluminium. Copper is also a popular material for heat sinks. With a thermal conductivity of up to 400 W/mK, it is an excellent heat conductor. However, due to its higher price and higher density of 8.96 g/cm³, it is only used when particularly high amounts of heat need to be dissipated in the shortest possible time. Copper heat sinks, e.g. with skived fins, are usually combined with a fan.

Active cooling systems use moving media such as air or water and provide high heat dissipation. Fans are one example. They offer high cooling performance, but can be noisy, are prone to dust build-up and require frequent maintenance. The situation is different with liquid heat sinks. In these, a cooling medium circulates within a closed system. Passive cooling solutions utilise natural heat conduction and convection. This makes them maintenance-free and allows them to be thermally optimised for the specific application.

Heat sinks can be secured using clips, rivets, solder pins or screws. The most suitable mounting method depends on the type of heat sink, the application and the quantity required. Mounting clips and springs reduce labour-intensive tasks when large quantities are involved. They are the preferred method of attachment for extruded PCB and plug-in heat sinks. Finger heat sinks are typically fitted with integrated solder tabs during the manufacturing process. Other heat sink variants can also be mounted using solder pins. If heat sinks are exposed to vibrations or shocks, such as in railway technology, screws provide the most secure connection.