The Complete Guide to Heat Sinks

Heat sinks are the coolest component in the manufacturing world. Seriously—despite their name, the entire purpose of these is to redirect heat from a machine or electrical component to keep them cool and from from burning out.

How do they achieve this, though? What makes a them tick?

If you want to become a heat sink expert, or at least learn enough about them to get your foot in the door, then you have come to the right place.

What Are Heat Sinks?

Heat sinks are critical for any kind of machine that uses electrical wiring, electrical component, microchip or anything else that naturally gives off heat. In the modern world, that covers pretty much everything.

If you are at least somewhat familiar with the term “heat sink”, then you probably associate it with either laptops, desktop computers, CPUs or manufacturing. There is obviously a huge difference in size for these kinds of parts, but they both rely on heat sinks for thermal regulation.

In laptops or PCs and other electronics , they do this by circulating heat from the CPU or microchips. Machines in mass production factories and warehouses usually use them to redirect hot air from electrical components and wiring.

These are not the only machines that are used though. You can also find them in refrigerators, cell phones, monitors/TVs, copy machines, automobiles, lighting, LEDs, internet cable and wireless transmission and certain types of lasers.

Regardless of their use, though, their purpose is the same: redirect heat without adding stress to an overburdened system

How Do They Work?

If you can think back to your K-12 science classes, you might remember that heat transfer occurs via radiation, convection, or conduction. Radiation generally applies to air and light waves. Convection happens in or because of water. That leaves conduction for solid materials like heat sinks.

Conduction happens any time that two solid objects with different temperatures contact one another. For example, setting a hot pan on a cool stove-top will both cool the pan and heat the surface of the stove. If the pan is significantly hotter than the stove, then the pan won’t lose as much heat. The stove, on the other hand, will gain much more.

If you’re still a bit confused, try thinking about a heat sink like a car’s radiator, as suggested by this article. In a car, the radiator reroutes heat from the car’s engine to keep the car running. It’s important to note that this only works because the radiator expels the heat it absorbs.

Heat sinks work the same way. To ensure that neither the machine it is in nor itself overheats, that heat sink transmits the heat to the surrounding cooler air. Therefore, may they contain some sort movement of air sometimes using a fan. While the heat sink itself absorbs the heat from another part of the machine, the movement of air shoots that heat elsewhere and, subsequently, cools down the heat sink.

Heat Sink Materials

Traditionally most heat sink manufacturers use one of two materials : copper or aluminum. Copper has a higher thermal conductivity than aluminum, but it is also heavier and more expensive. For these reasons, it’s pretty safe to say that the best heat sink material is aluminum.

Although aluminum is not quite as conductive as copper on its own, it has more than enough additional benefits to make up for it. From a radiation standpoint, aluminum is typically brighter than copper, meaning that it is better at reflecting heat from light sources. This is true even for unpolished aluminum. In addition, aluminum can be anodized in a multitude of colors.

Aluminum is inexpensive to manufacture, especially in comparison to copper. It is also incredibly lightweight and easy to manipulate. Both factors make aluminum ideal for larger and custom-configured heat sinks. These custom configurations are designed from extruded aluminum.

The main functionality of heat sinks depends on the fin arrangement. They are most effective when they cover the greatest possible surface area, so manufacturers design them with multiple layers (aka fins). These fins can use a pin, straight, or flared configurations.

Each of these configurations has its pros and cons. When the airflow is limited a pin fin heat sink is the most common on the market that can provide more surface area for standard degree of heat transfer.  As the heat requirements increase the fin heat sink can offer more economical and more configurations  to better transfer the heat.  The configurable design of the fins is the best overall for both performance and energy cost.

Forged Pin Heat Sink
Forged Pin Heat Sink
Aluminum extruded fin heat sink
Aluminum extruded fin heat sink

Do All Machines or Electrical Components Fit These Standard Fin Configurations?

No, so this is where customization and extruded aluminum come into play. Unlike copper, aluminum can be extruded (aka stretched and manipulated) during manufacturing to form more complex fin designs.

Manufacturers can also use extruded aluminum to fit additional parts like heat pipes, liquid cooling piping, chassis, and spreader bars.

Generally, these parts are made of the more traditional copper. Copper is not nearly as easy to stretch or format, though, meaning that manufacturers have to use multiple sheets of copper to design each piece then heat those pieces to mold them together. This creates excessive waste and can cost a lot of time. By using extruded aluminum, manufacturers can easily mold the base heat sink part to fit any additional components. It also cuts down on copper waste, which is both expensive and difficult to reuse. 

For a more comprehensive description of the differences between copper and aluminum heat sinks, see here

Ionthis Inc.

As one of the best start-to-finish manufacturers, we are well equipped to answer any question you have or point you in the right direction. More importantly, we are always ready and willing to teach you how to be cool.

If want to learn more about heat sinks, extrusions, sheet metal, or custom fabrication, check out Ionthis Inc.

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