If you are producing PCBs for different types of devices and equipment, it is essential to prioritize the board’s heat dissipation capabilities. Effective heat dissipation in PCBs can prevent performance problems and catastrophic failures from excessive temperatures. It is vital to choose a PCB equipped with appropriate heat dissipation components to avoid overheating and to ensure reliable performance.
Discover additional information regarding the issue of heat and gain insights on techniques for dissipating heat in PCBs.
Why Is Heat Dissipation A Problem In PCBs?
The flow of electric current through electronic components results in an increase in thermal load. Various factors, such as the circuit layout, power input, and device properties, influence the extent of heat an electronic component generates. Improper installation of parts, external factors, insufficient ventilation, and incorrect assembly are frequent causes of overheating in PCBs.
While PCBs can tolerate a certain amount of heat, elevated temperatures can result in significant problems. PCBs can experience several adverse effects due to excessive heat, including circuit line disruption, component oxidation, compromised structural integrity, and incompatible material dilation rates. These consequences can lead to a decline in the PCBs’ overall performance. If the PCB is exposed to excessive heat for a prolonged period, it can malfunction and even fail, causing permanent loss to the Printed circuit board.
Techniques Of Heat Dissipation In The PCB Industry
Considering the adverse effects of excessive heat, it is advisable to ensure that your PCB possesses heat dissipation capabilities. To dissipate heat from the Printed circuit board, several techniques can be employed, such as incorporating heat sinks or cooling fans, which are effective means of heat dissipation.
Discover the fundamental techniques for dissipating heat in Printed circuit boards by exploring the following methods:
1. Cooling Fans & Heat Sinks
Heat sinks are metallic components with high thermal conductivity and a significant surface area commonly utilized by PCB designers to dissipate heat. They are typically affixed to heat-generating features such as switching devices, enabling the component to transfer heat to the heat sink and dissipate it over its large surface area.
In addition to incorporating thermal dissipators in your PCBs and other device components, you can install cooling fans. These fans introduce excellent airflow into the device, facilitating rapid heat removal and preventing heat buildup. Typically, you can utilize cooling fans in high-current power supplies, which aid in more efficient and expeditious heat dissipation.
2. Use Thick Copper Traces
When designing a Printed circuit board for high-current applications, it is often advisable to incorporate thick or thick copper tracks. Wide copper traces provide an increased surface area for heat dissipation and distribution, allowing heat to dissipate more effectively.
3. Invest in Heat Pipes
In cases where the PCB is present in a compact application with limited space, heat pipes are an effective solution for heat dissipation. So these pipes use fluids like small quantities of acetone, water, ammonia, or nitrogen, to absorb heat. Once the sap gets in the heat and the pipe releases vapor that flows down. The condenser then condenses those vapors into liquid form. It allows the pipe to cycle continuously.
Companies that mostly prefer heat pipes seek a cost-effective and dependable method of passive heat transfer owing to their remarkable heat transfer capability. By incorporating these pipes, devices can attain good thermal conductivity while requiring minimal maintenance. Heat pipes are also incredibly silent, as they do not have any moving parts and are entirely free of vibrations.
4. Right Board Materials
Opting for board materials well-suited to dissipating heat is another technique that can help improve heat dissipation. Certain PCB materials lack the necessary properties to handle high temperatures effectively. Thus, it is crucial to select substances that possess heat-dissipating properties, significantly if your equipment exposes to high heat/temperatures. Choosing the polyimide base is an intelligent Option.
5. For thermal management
Flex PCBs are a suitable choice for heat dissipation because of their thin and flexible substances, which enable a larger surface-area-to-volume ratio. Another excellent option for heat dissipation is aluminum PCBs, which are a kind of metal-core circuit board that features a dielectric layer. So this layer assists in absorbing heat and transferring it to the aluminum layer, where the heat disperses. Aluminum-printed circuit boards are beneficial for high-energy appliances. For high-energy tasks, copper-printed circuit boards offer the best heat dissipation & thermal conductivity.
Ceramic PCBs are an excellent option for high-temperature and high-frequency offerings as they offer exceptional heat resistance and connectivity. These PCBs are usually constructed with either alumina or aluminum nitride and boast high heat conductivity, low coefficient of Heat expansion, and excellent versatility or chemical corrosion resistance. So this makes them ideal for use in a wide range of environments.
6. Use Thermal Via Arrays
To enhance heat dissipation and reduce thermal resistance, thermal via arrays are a great option. They work by increasing the area and mass of copper, resulting in decreased thermal resistance. Additionally, they allow for better conduction and are particularly useful for critical components that generate heat. As a result, you can place thermal via arrays close to heat sources to improve performance.
For businesses seeking to eliminate heat dissipators from their Printed circuit board, thermal via series are a popular option. Thermal via arrays can be combined with a pad in specific applications to conduct heat away from a device. So it improves the Printed circuit board Thermal dispersion and eliminates the requirement for heat sinks.
7. Implement Copper Coin Technology
Tiny particles of copper, known as copper coins, are typically embedded in PCBs beneath components that produce significant amounts of heat. This placement takes benefit of copper’s excellent heat conductivity. It allows the coins to draw heat from the elements and transfer it directly to the heat sink. Copper coin effectively dissipates heat, especially when only a few components generate the most heat.
Several shapes of localized solutions, such as T-Coins, C-Coins, and I-Coins, are available for use depending on the area shape. Once the routing process is complete, one can integrate the coin into a slot in the PCB, laminated & metalized to ensure a secure connection.
8. Optimize the PCB Layout
To ensure effective heat dissipation in a PCB layout, companies often follow best practices during the design phase. For example, they may place temperature-sensitive elements in more excellent areas, such as the bottom of the device, and avoid installing them on higher levels of heating equipment. Designers may also stagger multiple components resting on a level surface to improve ventilation. To achieve more accurate temperature readings of a PCB, a company may opt to place a thermometer in the Hottest zone.
A well-designed PCB layout prioritizes the installation of heat sources at a safe distance from one another to prevent excessive heat buildup. So, If the cooling fan is present, designers may consider placing high-heat generating elements downstream but installing low-heat Power-generating components upstream to optimize cooling. Professional PCB designers also study the device’s air circulation and strategically place high-heat creation devices based on airflow.
9. Integrated cooling methods
Integrated cooling techniques achieve more excellent thermal conductivity than traditional heatsink and fan setups. The principle involves directing a refrigerant through dedicated vias to the underside of processors, BGAs, or other heat-generating components.
The designer should determine the appropriate number of vias based on the criteria of a mounted element. Initially, the single via may be sufficient, but additional vias may be added depending on the fluid’s velocity and the component’s surface area.
In addition to the previously mentioned Embedded cooling method, there are other approaches, such as the internal cooling method. With this method, a heat exchanger is integrated directly into the board, eliminating the need for an Outside heat sink and cold plate, resulting in reduced weight and Printed circuit board assembly steps. However, these coolers necessitate a high density of thermal vias around the Cooling pathways.
· Cooling fans
This article discusses various cooling methods, including heatsinks, thermal vias, and heat pipes. While these methods rely on conduction to transfer heat, in multiple situations, this alone is insufficient. A cooling fan employs Thermal convective transfer, providing designers with a highly efficient means of dissipating heat from components.
The effectiveness of a cooling fan is determined by its capacity to move a specific magnitude of air from an appliance and its compatibility with the device’s layout. When selecting a fan, designers must take into account factors such as size, cost, and noise. However, the fan’s primary function is to move air, making capacity the most critical factor to consider when choosing the cooling fan.
· Soldering concentration
To minimize heat buildup on component leads, device joints should have even and uniform soldering thickness. Care must be taken when soldering near vias, as there is a risk of overfilling the hole, resulting in bumps on the lower side of the circuit board and a reduced contact area with the heat sink.
To prevent solder overflow, Printed circuit board designers have two options. The first is to reduce the via diameter to less than 0.3mm. With smaller vias, the layer tension of liquid solder in the via can better counteract gravitational force acting on a solder.
Testing is the second way to do it. It means putting a unique cover over the small hole so that when the solder is added, it doesn’t go into the hole.
· Peltier heat pump / Thermoelectric coolers (TEC)
It’s time to consider upgrading to more advanced methodologies in Printed circuit board cooling, such as thermoelectric cooling/Peltier pump methods. With these techniques, you can cool components to sub-ambient heat.
TECs are a preferred cooling solution in applications requiring precise temperature control, such as CCD cameras, microprocessors, laser diodes, and night-vision units. TECs provide Exact temperature management or faster response times compared to traditional cooling methods. Designers can combine TECs with air and Liquid cooling methods to increase the cooling capacity. It also extends the limits of air cooling for power processors.
10. PCB thermal vias design
The copper barrels conduct heat and run through the board from top to bottom. They are efficient Heat conductors that conduct heat away from essential electronic components. It makes them helpful in facilitating heat reduction from SMDs.
If there isn’t enough space on the upper side of the Printed circuit board for the cooling system, such as in the case of an integrated sensor or indicator. Or a densely packed board, one way to dissipate heat is by using thermal vias to transfer heat to the cooling unit, such as a heat sink and heat pipes.
11. Copper thickness & width of traces
In PCB thermal design, the width and thickness of copper pads or traces are crucial factors. The thickness of copper traces should be enough to offer a low-impedance way for the current flowing through them. The resistance of copper vias can cause significant power loss & heat generation, especially when they carry high current density. Therefore, we recommend sufficient trace thickness and width to minimize heat generation.
12. Minimizing Heat’s Impact on PCBs
Having learned the tactics, it is now essential to have a strategy to implement them. A critical process is to Divide the heat-generating elements from the heat-sensitive on the PCB. It allows for Directed Heat reduction efforts in a specific area and Prevents heat from affecting the Temperature-sensitive components.
When mounting the Printed circuit board vertically, we recommend placing heat-producing components on the top side. Additionally, it is beneficial to identify these components towards the side of the Printed circuit board. It reduces heat dissipation in an environment.
