What are heat sink types? Classification of Heat Sinks

The heat sink is a standard accessory for electronic equipment. It has many types and is called by different names according to different classification methods. To choose the right heat sink for cooling electronic applications, it is helpful to know the definition, uses, and advantages of different types of heat sinks. The following heat sink manufacturer, Winshare Thermal, will share with you through this article the 3 ways to classify heat sinks, hopefully give you a better understanding of the various types of heat sinks.

Heat sinks can be classified by the following 3 ways:

• Classification by airflow

• Classification by material

• Classification by manufacturing process

Classification by airflow

Passive Heat Sink

Passive heat sinks do not rely on forced airflow (fans) and are considered more reliable than active solutions. A good example is a heat sink that doubles as an equipment enclosure. In this example, heat is transferred from one or more heat-generating components to one or more enclosure walls. These walls typically have an array of fins exposed to outside ambient air.

Active Heat Sink

Heat sink assemblies with power devices such as fans or blowers near the surface of the heat exchanger are active heat sinks. These also include heat sinks that rely on pumping fluid to remove latent heat from the heat source. Because active heat sinks rely on forcing air through the fin area, they are more efficient - which means smaller and lighter heat sink designs.

Classification by material

Heat sink materials used for electronic cooling applications are almost always aluminum or copper.

Aluminum Heat Sink

Aluminum is lightweight and easy, and cost-effective to manufacture, making it the ideal choice for most heat sinks. Alloys 6061 and 6063 are the most common alloys, while 1050 and 1100 are purer and have slightly higher electrical conductivity. Its ability to move heat, or thermal conductivity, is about half of copper. This limits the distance that heat can be moved and conducted away from the heat source at the bottom of the heat sink.

Copper Heat Sink

Copper has a thermal conductivity of about 400 W/m-K and is used when heat sinks need improved performance. A typical alloy for copper sheets is CDA110 (391 w/mK). The disadvantage is that copper is three times heavier than aluminum and costs twice as much. It also works slightly slower than aluminum. Some heat sinks (such as bonded fins) can be made from two materials: one for the base and the other for the fins.

Classification by manufacturing proces

The most common manufacturing methods for heat sinks combined with heat pipes or heat equalization plates are CNC machining, forging, die casting, zipper fins, extrusion, bonding, and skiving.

CNC machined heat sinks

Complex design options and high thermal conductivity are two of the main advantages of CNC machined heat sinks. Their somewhat high manufacturing costs and relatively slow manufacturing throughput preclude them from being an inexpensive and high-volume option.

Forged and Die-Cast Heat Sinks

Like forged heat sinks, die-cast heat sinks offer a lower unit cost for high-volume production. However, upfront processing costs are too high for small to medium volumes. Die-cast and cold-forged heat sinks offer excellent thermal performance. Forged heat sinks offer design flexibility for complex heat sinks. In contrast, die-cast heat sinks are limited to thicker fins, making them ideal for housing covers used in natural convection applications.

For more information about the different types of Heatsink processing, you can check out our product section "Heatsink", or you can contact us by message or email.