Thermal management is a key aspect of enclosure design. The amount of heat generated gathers inside the electronics enclosure, consequently damaging the components. Not only does constant overheating decrease the life expectancy of a device, but also results in product failure. Small-sized handheld gadgets, heavier outdoor devices, and controllers are particularly vulnerable to overheating. That is why, when it comes to optimizing the enclosure layout and minimizing failure, electrical engineers and designers pay special attention to the thermal behavior of enclosure materials. Following are some of the critical aspects of thermal analysis:
Every enclosure requires ventilation so that the generated heat can escape. After all, it cannot just pass through solid metal. However, random ventilation will not do; it must be the right combination of functionality and aesthetics.
What Sort of Ventilation Does the Product Need?
First and foremost, you must engineer the ventilation rates of the electronics carefully, especially in the case of larger heat-producing devices. In the case of items with low-power components, you still have some leeway. Engineering the ventilation requires you to first calculate the required flow rate by the energy balance. Now, you need to figure out how to get that flow rate through the enclosure. If you’re using forced ventilation, like fans, the process becomes quite straightforward. Air flows in and out of the enclosure without any restrictions. But forced ventilation is more common in high power dissipation’s. Natural convection makes more sense for low power output, and this involves a variety of openings.
A few of the most common types of openings include:
- Cutouts: Nowadays, laser cutting is the preferred method of creating cutouts in the enclosure as no tooling is required. As long as you are able to draw the cutout, it can be cut with a laser.
- Perforated Material: If you need many holes for filtration and ventilation, opt for perforated materials, instead. This is a more cost-effective method compared to individually created hundreds of laser-cut holes. Perforated metals are versatile, lightweight, durable, and easy on the eyes. Moreover, the process also overcomes the issue of cutout density.
- Louvers: These components are ideal for imparting ventilation to the electronics enclosure while also protecting against the accidental entry of foreign objects or dirt inside due to the opening’s overhang.
Most Widely Used Thermal Management Measures
Some of the most popular design elements for improving the thermal transfer features of electronic items via conduction include:
- Thermal Interface Material
Such materials serve as fillers for the gaps located between the heatsinks and the heat source. Usually, they possess greater thermal conductivity and improves the efficiency of the thermal management process across the whole system.
The metal components that remain in contact with the heat source for siphoning heat via conduction and often through radiation or conduction are called heatsinks. Normally, metallic substances like copper or aluminum are good heatsink materials since the thermal conductivity of these metals is considerably high and directly proportional to their heat dissipation capabilities. As the heat transfer process occurs through the surfaces, the shape and design of the heatsinks feature large surface areas.
- Heat Pipes
Heat pipes consist of either sealed aluminum or copper tubes, or fluid-filled tubes. When placed against a hot surface, the liquid absorbs heat, boils, and turns into vapor.
- Thermoelectric Modules
These components are manufactured based on the Peltier effects, where components are cooled or heated depending on the application of a current to the device. Thermoelectric modules must always be used in sync with heat-sinks. Otherwise, the possibility of failure or overheating increases.
- Thermal Adhesives or Grease
This is another common heat transport mechanism. Available in either thermally conductive grease or adhesive form, one of the biggest benefits is the bonding of components together that would otherwise have never bonded mechanically.
So, numerous options are available to electrical designers. However, figuring out the perfect blend of components that ensure efficient and reliable heat dissipation is a lot harder than it sounds, especially when you consider how the designers and engineers need to keep the product as compact as possible.
Overcoming Thermal Management Problems
Designers and engineers must work with pre-determined funds when it comes to implementing thermal management features in electronic enclosures. So, they do not have the luxury of trial-and-error. While the only way to ensure the durability of an electronic product in the traditional design processes involves performing multiple design iterations until all the criteria are met, they lack the time and resources to build different physical prototypes.
No wonder engineers and designers seek accuracy and efficiency which are achievable by performing a thermal simulation on the electronics enclosure before the actual item is produced. This simulation is useful since the manufacturers can discover the answers to various critical questions, including the effectiveness of the cooling system, the impact of the chosen material on heat transfer, and executing possible design changes. Depending on the nature of the electrical product, a simulation can help them find the solutions to other problems as well.
- Are Thermal Simulations a Viable Option?
Electrical engineers and designers are faced with numerous choices when it comes to producing a solid enclosure for heat dissipation in small electronic items. However, it is impossible to assess all the options quickly and choose the perfect solution based on the specified application. This is where a thermal simulation comes in handy. They are extremely useful for creating more compact and safer devices, thereby allowing engineers to experiment with more unique designs.
Apart from the various design iterations, it is equally important to implement the design changes at the right stage. Ideally, any alterations must be carried out early on to minimize the cost of the design changes. If it takes place at a later stage, the scope of the design changes is narrowed down tremendously with room for only small, incremental modifications.
However, the widespread usage of thermal simulations does not wholly eliminate the need for physical tests. Why? Because virtual and physical prototyping was never meant to be mutually exclusive; they are complementary at best. Thanks to virtual simulations, however, the days, weeks, or even months it took to finish the physical testing process has been reduced to hours, maybe even minutes.
You should always choose the right electronic enclosure for your device. But it is easier said than done. Creating a perfect enclosure involves a number of complicated processes like thermal management. However, various advanced thermal management techniques have made it easier for manufacturers to achieve heat dissipation in modern electronics.