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Importance of Heat Sink PCB in Electrical Devices

Printed circuit boards are an essential part of most electronic designs. The use of heat sinks on PCB is a big development in the technology world. Heat sink technology offers the best method for dissipating heat. This allows heat to spread throughout a circuit.

What is a Heat Sink PCB?

heat sink on pcb

Heat sink PCB is a type of circuit board that can dissipate high surface temperatures. Power semiconductors, diodes, and resistors are the causes of this temperature. This type of PCB is becoming popular in the world today. Most printed circuit boards feature a heat sink.

Heat sink PCBs are one of the best forms of thermal management. This circuit board works by dissipating heat from critical components. Heat sink PCB is ideal for use in applications that generate heat. This PCB absorbs or dissipates heat when the heat affects the device.

Heat sink printed circuit boards help to cool components of electronic devices that produce much heat. This type of PCB is ideal for use in high-temperature applications. Most electronics use heat sink boards since they help to dissipate heat. One might wonder what heat sink PCBs do. These boards take away heat from any component that generates it.

Heatsink PCB features a lot of benefits, making it the best option for most devices. Today’s mechanical and electrical devices use these PCBs. One important benefit of using these boards is that they improve performance. Most electronics that make use of these boards have a longer lifespan. When a component of a device generates too much heat, it can cause havoc.

Therefore, a heat sink PCB is a type of board that dissipates or absorbs heat. As it was earlier said, heat build-up in some devices can cause system failure or explosion. Using heat sinks in electronics and mechanical devices can prevent any of this from occurring.

Heat sinks can also be heat spreaders or coolers. They are like radiators that evaporate the heat they absorb into the atmosphere.

Why Heat Sink PCBs are Important in Electronic Circuits

All electrical components in a circuit produce heat while the circuit is functioning. High-power devices such as power transistors, LEDs, and lasers produce heat. Some of these components can’t dissipate heat since they have a low dissipation capability.

Heat build-up in the component can result in total failure or premature failure in the device. Therefore, heat sink boards are a perfect way to conquer these problems. These circuit boards are used in most applications because of their cooling functions. PCB manufacturers include a heat sink in PCB due to the numerous benefits it offers.

Passive Heat Exchange

Heat sink PCBs feature a large surface area that cools off. These boards act as passive heat exchangers. The component of a device that can’t control its temperature needs heat sink PCBs. To improve performance, every heat in a component of an electronic circuit must be dissipated. This will help to prevent the component from experiencing any failure.

Maintains Thermal Stability

Heat sinks in PCB help to maintain thermal stability in any electronic device. Thermal stability is very important for electronic components of any circuit. Heat sink PCBs can survive in any temperature because of their cooling ability. This is a major reason these PCBs are employed in high-performance applications.

Heat sinks don’t only dissipate heat; they also provide heat during low temperatures. They do this by generating thermal energy for the smooth functioning of the circuit.

Spreads heat

Heat sinks serve as heat spreaders in some applications. For instance, a heat sink PCB functions as covers on the memory of a computer. Heat sinks also help to cool off the graphic processors and CPU of computers.

Prevents system failure

Heat sinks prevent system failure in a circuit. The absence of a heat sink can cause the failure of components. It is advisable to implement a heat sink in a PCB to prevent overheating. Component failure is one of the common problems of electronics or electrical devices.

Different types of mechanical and electronic devices generate heat which heat sinks absorb. Heat sink PCBs play significant roles in mechanical, electronic, nuclear, and solar processes.

Types of Heat Sink

Heat sinks are available in various types. Each of these types has its function. However, they share some common characteristics or features. Heat sinks are mostly made from metal like aluminum or copper. The commonest designs for a heat sink are the fin layout. Some versions utilize stamping and pins to increase the surface area and heat transfer rate.

Passive heat sink

A passive heat sink doesn’t feature additional products while cooling a component. It isn’t assisted by additional processes. These heat sinks don’t have any mechanical components. They dissipate heat through the convection process. When you use this heat sink on PCB, it gives reliable results.  Experts recommend that engineers should maintain the flow of air across the fins of this heat sink.

Passive heat sinks serve as a standalone solution since they don’t use other cooling methods. These heat sinks are bigger than active heat sinks. Passive heat sinks disperse absorbed heat via the direct contact between them.

Active heat sink

This type of heat sink uses additional products to enhance its cooling capacity. Active heat sinks use powered processes like water pumps and fans. These processes or products help to increase the heat transfer rate. In some electronic systems, these coolers run off the internal power supply. This type of heat sink isn’t ideal for long-term applications. This is because it has moving parts.

Active heat sinks make use of one or more fans. These fans are either above or on the side of the fin stack. Some advanced active heat sinks use water to transfer heat from a source.

Types of Heat Sink Based on Material

Aluminum heat sink

An aluminum heat sink is a less expensive choice for heat sinks. This type of heat sink is designed in a way that the generated heat escapes via some thin metal fins. Aluminum is the commonest material used in heat sinks. The thermal conductivity of aluminum is different from copper. The thermal conductivity of the metal affects the heat sink’s heat transferring capacity.

Copper heat sink

Most heat sinks are made of copper. Copper is a good thermal conductor and has got great heat transfer capabilities. This type of heat sink draws away heat from the device you want to cool. Heat sink PCB made of copper is more expensive.  Most PCB heatsink designs use copper.

Pinned heat sink

A pinned heat sink is an alternative design fin heat sink. The core block of the pinned heat sinks features a cluster of rods or pins that extends outward or upward. This type of heat sink has a better overall surface. But, they don’t offer good performance improvement in most applications.

Finned heat sink

This type of heat sink is designed from a block of metal. This metal is available in a large number of thin plates that extend away from the central block. Finned heat sink features a better surface area. This makes it more effective in transferring heat away from the component. The manufacturing and designing of this heat sink involve either die-cast or forged models.

Heat Sink Types Based on Manufacturing Techniques

Circuit board heat sink

Various manufacturing methods are used in manufacturing heat sinks.

Stamped heat sink

This type of heat sink features stamped metals. These metals can form a certain shape. The stamp designs the heat sinks anytime metal moves via the stamping machine. Stamped heat sinks are ideal for low-power applications.

Bonded heat sink

This type of heat sink is ideal for large applications that demand sensible performance. Bonded heat sinks are designed by combining separate fins of metal to the heat sink’s base. There are two different methods for doing this. They are the brazing and the thermal epoxy methods.

Skived heat sink

Skived heat sinks employ skiving for their manufacturing. Skiving is the use of fine blocks of metals for manufacturing heat sinks. Skived heat sinks can be high or medium-performing heat sinks.

Swaged heat sink

Swaged heat sinks are medium-performing heat sinks. Swaging is a manufacturing technique that involves a cold working forging process. However, it can undergo a hot working process.

Forged heat sink

Forging involves utilizing compressive forces. This technique is used for manufacturing aluminum and copper heat sinks.

Machining heat sink

This type of heat sink uses a machining process for its manufacturing. Gangsaw helps to eliminate a block of material. This type of manufacturing process is expensive since a lot of metal may waste.

Applications of Heat Sink PCB

Heat sink PCBs are used in several applications due to the functions they perform. These circuit boards are ideal for high-performance applications. They are also suitable for use in devices that produce a high amount of heat.

LEDs

Heat sink PCBs are commonly used in Light-emitting diodes (LED). These PCBs provide effective cooling for LED pcb. Heat sink circuit boards prevent excess heat from damaging LEDs. Most high-power LEDs feature heat sink PCBs.

Computers

Heat sink PCBs are a common component of computers. The CPU of computers needs a heat sink. Electrical activity in the CPU produces a good amount of heat. This may cause damage to the chipset. A heat sink helps to offer a good path for heat to pass through. The CPU comes with a heat sink. Some manufacturers use a particular type of heat sink for their CPUs.

Industrial facilities

Most industrial devices generate heat while in use. Therefore, a heat sink PCB is ideal for use in industrial equipment. Heat sinks are connected on a circuit board because of their cooling properties. They reduce the amount of absorbed heat in a mechanical device while running.

Soldering

During the soldering process, heat sinks help to protect electronic components. Some components need the protection of a heat sink during soldering.

Consumer products

Heat sink PCBs are used in most consumer products. Some electronic devices in the home come with heat sinks. This is because some components of these devices generate a lot of heat. Therefore, heat sink PCBs help to dissipate heat in these devices.

The Limitations of Heat Sink PCB

The cooling of electronic devices is important for their long-lasting function. The need for circuit bard cooling has continued to increase. Heat Sink PCBs help to dissipate heat in electronic devices. The importance of the use of heat sinks in PCBs can’t be overemphasized.

There are different types of heat sink PCB with different thermal resistance values. These PCBs ensure cooling.  Heat sink PCBs have their challenges. One of the major challenges is the joining of the circuit board with the heat sink.

Another challenge is the aerial use of thermal adhesive without air pockets between the components.  The properties of the thermal adhesive caused this problem. However, thermal engineers achieved good distribution by using pressure pins. The vacuum joining process presents a reliable result.

The dissipation of heat loss from chips is a major issue for developers. There are several ways to link a heat sink to the source of the heat. The fabrication of a heat sink PCB involves creating a separate metal heat sink. Then, manufacturers use liquid adhesive to attach this heat sink to a finished board.

Heat Sink Dissipation Method

Heat sink PCBs use some methods to dissipate heat which are:

  • Heat transfer compounds
  • Metal heat-conducting plate
  • Higher copper thickness
  • Metal core

Heat transfer compounds

For heat sink PCBs, fabricators use a screen-printing procedure to apply the heat transfer compound to the silkscreen. The layer’s thickness ranges between 100 – 150 μm.

Metal core

Rather than using the standard base material, a copper or aluminum sheet is used here.  A prepreg is used to laminate a copper foil onto a metal core.

Higher copper thicknesses

When it comes to thick-copper boards, the copper absorbs the heat and directly dissipates it. The copper thicknesses are 400 μm, 210 μm, and 105 μm. This method involves high-cost production since the conductor structure requires much effort.

Metal heat-conducting plate

In this method, a heat sink PCB goes through the standard production process. Manufacturers use a prepreg to press mold the PCB to the metal heat-conducting plate.

Factors to Consider in Heat Sink Design

The design of a PCB is a very complex process. The importance of heat sinks in PCB can’t be overstressed. Engineers need to consider some factors when implementing a heat sink on PCB. Heat sinks transmit thermal energy from electronic components into a cooling medium.

Several factors determine the performance of heat sinks. The material’s thermal conductivity and attachment method are some of these factors. Engineers can determine the parameters of a heat sink via analysis and modeling.

Heat sink materials

Alloys, aluminum, and copper are materials used for designing heat sinks. Copper is a good thermal conductor that resists corrosion and absorbs heat. This material is ideal for heat sinks due to its properties. However, it is a more expensive option.

Diamond is another ideal material for thermal applications. This is because it features lattice vibrations. Another alternative is the bonding of aluminum and copper. In this case, aluminum is the dominant material due to its lightweight. This is a perfect combination for heat sinks in computers.

Heat sink fins

Heat sinks feature fins in their design. These fins offer the necessary surface area for heat dissipation. They cool the heat source. The fin’s efficiency determines the performance of the heat sink. Once there is a flow of heat through the fin the temperature reduces from the base.

The arrangement and location of the fins also affect the performance of the heat sink. The design and shape of the fins will greatly determine the heat sink’s performance.

Thermal resistance

Thermal resistance determines how heat sinks perform. This factor determines heat flow. In order to achieve an efficient heat sink, the thermal management system needs to be combined with a cost-effective design.

Attachment methods

There are different methods of attaching heat sinks to the component of a device. Using the appropriate method helps to enhance the heat sink’s thermal performance. Thermal tape, standoff spacers, epoxy, and flat spring clips are examples of attachment methods.

Characteristics of a Good Heat Sink

A good heat sink features some characteristics that make them ideal in most applications. The characteristics of this heat sink are;

  • Heat dissipation correlates with the temperature difference between the ambient temperature and the device.
  • The mounting method is very critical. It uses screws rather than utilizing glue, clips, or sticky tape.
  • Heat dissipation correlates with the fins’ surface area. Therefore, it should have a very large surface.
  • Flat surface must have contact with the source of heat. This is very important as it allows a layer of thermal compound to minimize thermal resistance between the devices.
  • Heat sink design must enable free flow of air through the fins.

PCB Heat Dissipation Techniques

As PCBs are a core aspect of electronic devices, heat dissipation techniques are very important. Most electronic devices produce heat while they are running. Heat sink PCB helps to spread heat across components in a circuit. Below are some heat dissipation techniques;

Use cooling fans and heat sinks

If a printed circuit board generates a high amount of heat. You will have to incorporate fans and heat sinks in the design. Manufacturers attach heat sinks to components that produce the most heat. Power transistors, CPUs, and voltage regulators are such components. Here, the heat sinks are on the PCB. You can also install a cooling fan to help discharge the hot air in the environment.

Thermal via arrays

You can make use of thermal via arrays to transform a PCB into an onboard heat sink. The idea behind this is for flow of heat from the components to the copper area. Then the heat dissipates via the air from the vias.

Thermal via array must feature a large diameter to allow effective dissipation of heat. The vias must feature padded holes that connect to the copper area. More thermal vias also help dissipation of heat.

Use wider traces

Ensure you increase the trace’s width to improve heat dissipation to the air. This will help to reduce the trace’s thermal resistance and also minimize heat spots. Good copper trace thickness can offer a low impedance path.

These heat dissipation techniques are very important in electronics. Heat sinks play a significant role in the dissipation of heat in electronic devices. Components like power transistors and microcontrollers often generate heat. This happens especially when the load current rises.

Frequently Asked Questions

How do you calculate heat sink performance?

The performance of heat sinks is also known as thermal resistance. It is measured in °C/W. If a heat sink has a thermal load of 50W and the heat source rises by 20 °C. One can say the heat sink rating is 20/50 °C/W. This is equal to 0.40 °C/W.

How can the impact of heat on PCBs be minimized?

To do this, separate heat-sensitive components and heat-generating ones on the PCB. This can help you concentrate heat dissipation to a certain area. Doing this will also prevent the heat from going towards the heat-sensitive components. Place heat-producing components on the top when mounting the PCB vertically. You can reduce the heat dissipation path by placing the components towards the PCB’s edge.

What is a thermal simulation in PCB?

Thermal simulation locates the temperature of a thermal hotspot in a printed circuit board. Locating the thermal hotspots help to prevent the risk of failure in devices.

Conclusion

Electronic components can operate within a definite temperature range. When the temperature around these components rises beyond the upper limit, there can be a breakdown. Excessive heat can have a negative effect on the performance of the component.

For instance, MCU uses more energy at high temperatures. The lifespan of an electronic device will reduce if it is exposed to too much heat.  Too much heat can lead to premature failure of components. Therefore a heat sink PCB is an ideal choice for most electronics.