May 19, 2022 Edward Nelson
If you have any experience with electronic device design, you're likely aware of the importance of heat sinks. If not, it is critical to understand where heat comes from at the board level. In an electronic device, electricity doesn't always flow through the various components at a steady rate. Instead, it often meets several elements that produce resistance, and as this occurs, the excess energy is released in the form of heat. Since personal computers and other devices constantly move electricity around, they are capable of generating substantial amounts of heat, which could potentially damage associated components. To prevent this, designers incorporate heat sinks, which are specialized components used to keep the device cool.
Although heat sinks may be found in a variety of designs, they all regulate device temperature by coupling a heat-generating component to an element capable of removing heat. The latter is generally a fluid or a vent that allows the dissipated heat to escape into the air. It is necessary for the cooling component to have a large surface area since more heat can escape with such a design. Despite the fact that every electronic device generates some level of heat, not all require heat sinks. When deciding whether a heat sink is needed, it is essential to use the board's datasheet to calculate thermal resistance and power dissipated.
Heat sinks are generally produced using copper or aluminum alloys, which both feature sufficient levels of thermal resistance. Aluminum alloy 1050 or 6060/61 may be chosen depending on the application. The former offers a higher thermal conductivity but is generally soft and more prone to fractures, while the opposite is true of the 6060 and 6061 classes of aluminum. Copper is more dense and expensive than aluminum, but it carries the benefit of having nearly twice the thermal conductivity. As a result, it is commonly used in professional applications.
When determining the efficacy of a heat sink component, it is necessary to consider several factors, including the material, size, transfer coefficient, and airflow rate. As previously stated, the material determines thermal conductivity, which is the most significant predictor of performance. Sharing similar importance is the heat sink's size, particularly its surface area, since the surface area is directly correlated to the magnitude of cooling. The heat transfer coefficient can be calculated using the diameter, thermal conductivity, and distance between fins. This coefficient is integral to the equation, allowing you to determine the total cooling capacity.
Depending on the design, heat sinks can be manufactured through any number of strategies. Extrusion is one popular manufacturing method that involves forcing heated metal through a cast in order to change its shape. This process can also be completed using cold metal, although it is employed less commonly in heat sink production. Regardless of whether the manufacturer is using cold or hot extrusion, a more malleable material is generally preferred. As a result, aluminum 1050 is preferentially chosen over copper.
Another manufacturing process commonly used for heat sink production is skiving, in which precision tools are used to create thin slices from the parent material. This method is particularly beneficial for creating fins since it allows construction from a single piece of metal. Additionally, due to the nature of the skiving tool, the non-contact side of the fin will be rough with several small hills, thereby increasing its surface area. With recent progress in additive manufacturing, 3D printing has also become a popular alternative to conventional processes. When implementing 3D printing, heat sinks turn out smaller and lighter while still maintaining their effectiveness. These factors lead to reduced electromagnetic interference and cost savings.
When you are in the market for heat sink parts or any other board-level components, Aerospace Simplified has you covered with rapid lead times and significant cost savings. We are an AS9120B, ISO 9001:2015, and FAA AC 00-56B accredited enterprise owned and operated by ASAP Semiconductor, and we are dedicated to providing customers with the highest quality components possible. As such, we regularly subject our inventory to stringent testing, including visual inspection, document verification, cross-referencing, and other measures as necessary. We invite you to begin the purchasing process today with the submission of an Instant RFQ form.
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