Here’s a piece of trivia for you. Name one of the oldest forms of cooling for electronics. If you guessed heat sinks, you’re right! Yet do you know why it’s the oldest? How does it work? And that it’s still around even in the latest computers? Read on to find the answers to these questions and more

What is a Heat Sink? 

A heat sink is a passive heat exchanger. It disperses the heat generated from another object like an electronic or a mechanical device into a fluid medium like air. This allows regulation of the device’s temperature. Heat sinks are most commonly used in computers, but are also found in cell phones, DVD players, and even refrigerators. 

Heat sinks were an essential part of passive cooling, one of the oldest electronics cooling technologies. Passive cooling was a heat sink attached to a computer’s CPU. Fanless design is a descendant of passive cooling.

Passive cooling worked fine when computers were used for less energy-intensive tasks. As more demands were made on the CPU like gaming or number-crunching, more electricity was poured into it. This led to an increase in heat as discussed in PC Cooling: Why It is Important and What are Your Options. Active cooling systems which will be discussed below were developed to handle the excess heat. Heat sinks are still fundamental to computers and as important as any other component.

Is a Heat Sink Necessary?

Very. Having a heat sink is critical for computers. A CPU is prone to overheating because some of its components produce heat. This can burn or fry it. 

The heat sink is designed to absorb the heat coming from the CPU, then disperse the heat away from its components.  

What Do Heat Sinks Do?

A heat sink is a piece of metal that sits on top of a computer chip like a CPU. The part that makes direct contact is known as the heat, base, or cooling plate. Heat is drawn away via this plate via heat pipes to the heat sink which looks like an array of metal fins. There the heat is slowly dissipated into the air. 

What are the Types of Heat Sinks?

Heat sinks are generally broken down into two types.


Heat sinks that dissipate excess heat by themselves are referred to as “passive heat sinks”. 


Cooling systems that use fans on heat sinks to dissipate heat are called “active heat sinks”. They are very common in modern computers since they allow CPUs to operate at much higher temperatures.

How are Heat Sinks Made?

Best Materials for Heat Sink

Heat sinks need to be made of material able to absorb and dissipate excess heat readily without becoming too hot themselves. This is why today’s heat sinks are primarily made of aluminum, copper, or a combination of both. 


Aluminum is the most common material. The metal is lightweight and has relatively good thermal conductivity. 


Copper has even better thermal conductivity than aluminum. Unfortunately, it’s heavy and expensive. 

Heat Sink Manufacture & Design 

Heat sinks are manufactured in various ways. The processes, materials used, and the designs affect both cost and performance. 

Extruded Heat Sinks

The majority of today’s heat sinks are made from extruded, or die-shaped, aluminum. They are inexpensive to make and easy to customize. Performance of extruded heat sinks range from low to high.

Bonded Heat Sinks

Advantage of these heat sinks is that the base material and cooling fins can be different. This allows improved thermal performance while adding a minimal amount of weight. They are normally used for applications that require large-sized heat sinks. Bonded heat sinks generally offer moderate performance but are expensive to produce.

Skived Heat Sinks

Heat sinks produced through this method are normally made from copper. Design flexibility is high and provides medium to high performance dissipating heat. Unfortunately, skived heat sinks are heavy.

Stamped Heat Sinks

Stamped heat sinks are inexpensive to make thanks to their manufacturing process. Heat disbursement is considered low; most are used for low-power applications. 

Forged Heat Sinks

Forged heat sinks are made by compressing aluminum or copper. Performance is medium. They are inexpensive to make in high volumes but design choices are limited. 

CNC Machined Heat Sinks

CNC machined heat sinks offer high thermal conductivity and can be had in highly complex designs. This makes them very expensive and time-consuming to make. 

Uses of Heat Sinks in Fanless Design 

The increased demands on the CPU led to the development of active heat sink systems. Many industries though could not use these PCs. They still wanted similar computing power without the fans.

In response, computer manufacturers designed PCs that were more powerful than past ones without drawing in more electricity. Less electricity meant less heat. This low power requirement saw the rise in demand for PCs with heat sinks across the world. 

PCs with fanless design strictly use heat sinks to cool them. Examples of use include:

  • Companies like Ulterra were producing metal particulate and graphite dust as part of its manufacturing process. These were sucked in by their computers’ fans which destroyed interior components, costing the company $300 – $400 each to replace. The company switched to an embedded PC with fanless design to prevent their destruction. 
  • Healthcare facilities are extremely mindful of airborne pathogens like hospital-acquired infection and COVID-19. Fanned computers easily circulate these particles as they suck in air and blow it out to keep cool. That’s why acute care Bravera Health had fanless design a top priority for its medical cart computers. They would be used in the OR and similar departments, and needed to be as sterile as possible. 

Closing Comments

Heat sinks are one of the oldest methods used in PC cooling and they’re still found in modern computers and similar electronics. If you’re looking into how they can be used in fanless computers to work with your company, contact a representative from Cybernet. 

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