Printed Circuit Board Assemblies
The work environment in which printed circuit board assemblies (PCBAs) are used can affect their performance. Harsh environments can include excess sulfur which can corrode the copper foil on PCBs. This can occur even with the right coatings and processes in place. Other harsh conditions that may impact a PCB’s performance are power surges, electromagnetic interference (EMI), and moisture.
The most common materials used to make a printed circuit board assemblies are not able to withstand these types of environmental challenges. For example, the standard FR-4 PCB material can only withstand extreme temperatures for short periods of time. During this time, the material can expand or contract, affecting the connection between copper traces and components. This can cause the circuit to malfunction or fail.
For this reason, some PCBs are designed to withstand harsher environments. These are typically made of materials such as aluminum and other metals. They can be manufactured using a wide variety of techniques such as soldering, bonding and riveting. They can also be molded to create rigid products like electronic enclosures.
Can Printed Circuit Board Assemblies Withstand Harsh Environments?
PCBs in aerospace equipment must be able to withstand extremely harsh conditions for long periods of time. These conditions can include a wide range of temperatures, humidity and other factors such as chemical exposures. They must also be able to withstand mechanical vibrations and shocks.
The use of high-quality copper traces can improve a PCB’s ability to handle heat. However, it is important to ensure that these traces are properly shielded from external influences and that the PCB assembly is adequately cooled. This will help to prevent thermal damage from occurring on the copper and other components.
In addition to reducing the potential for corrosion, shielding traces can reduce the number of solder joints in the PCB. This can help to increase the lifespan of the assembly.
While specialized PCBs can be designed to withstand a broad range of temperatures, it’s also important to consider the temperature limits of individual components. Certain electronic components like ICs, transistors, and capacitors have specific temperature limits beyond which they can malfunction or become permanently damaged.
Other factors that can impact a PCB’s ability to withstand harsh environments are the physical characteristics of the circuit board itself and its design and construction. PCBs can be reinforced with a waterproof conformal coating such as silicone, acrylic, or polyurethane or potted in an epoxy, silicon, or polyimide compound to protect it from moisture and other environmental elements.
It’s crucial that a PCB manufacturer evaluates the work environment in which it will be used to determine if any special materials are needed to ensure optimum performance. This can help to minimize the risk of failure and costly repairs. For instance, if a PCB will be exposed to excess sulfur, a special coating can be applied to the surface to prevent creep corrosion.
Another way to improve a PCB’s ability to fend off harsh environments is to use a copper-clad laminate with a lower sulfur content than standard FR-4. This can reduce the chances of oxidation, which is one of the most common causes of failure in electronics.