Strategies for Flexible PCBs
Most electronic components dissipate some heat when current flows through them, and the power loss from the resistance of copper traces and vias also contributes to some heat generation. A circuit board’s thermal management strategies must be designed to transport that heat away from critical components, and to keep the entire board within safe temperature limits. This can be achieved with passive cooling methods like cooling fans, or active thermal design techniques that involve using a system that pulls cool air or liquid past hot components during operation.
When designing a circuit board, it’s important to consider the thermal regulation of the entire design right from the prototype phase. This involves performing thermal analyses of dielectric materials, evaluating the layout of components and examining the way that heat is transferred around the board. The use of thick traces, thermal via stitching and even thermal sinks are effective ways to transport heat away from critical components, which helps to reduce the risk of failure due to overheating.
To optimize the performance of a PCB, designers should choose dielectric materials that have excellent thermal properties. They should also perform a thermal analysis of the material to verify its stability, such as the thermogravimetric analysis (TGA). The TGA is an efficient method for measuring the change in mass of a sample with temperature. It can identify any anomalies that could indicate thermal stress, such as cracking and discoloration, which are signs of a poor thermal regulation.
Thick copper traces improve a circuit board’s thermal conductivity by spreading the current over a larger surface area. This means that the heat will dissipate more quickly, and the overall board will be able to cool down faster. For high-power applications, designers should opt for filled and capped thermal via arrays, which provide even better performance by reducing the PCB’s thermal resistance by adding more copper to the structure.
Thermal Management Strategies for Flexible PCBs
Choosing the best location for a circuit’s high-power components is crucial for optimal thermal management. Components that dissipate more heat should be placed near areas with the greatest heat removal capacity. It’s also a good idea to distribute the power components evenly across the board. This will prevent hot spots from forming, which can compromise the integrity of the board.
As well as thermal vias, a PCB’s substrate can help with heat transfer by providing a higher effective thermal conductivity than FR4. Ceramic and metallic substrates typically have much lower thermal resistance than FR4, and they also offer superior electrical performance.
When choosing a PCB material, it’s also important to consider its chemical and environmental stability. For example, some PCB materials, such as FR4, are susceptible to chemical degradation from volatile compounds. Other options, such as intrinsically black polyimide films, have superior environmental and chemical stability. This allows them to withstand harsh environments, including extreme temperatures and humidity levels. This makes them a great option for flexible printed circuit boards.
In industrial settings, flexible pcb are essential for automation and control systems. They are utilized in robotics, machinery control panels, sensors, and data acquisition systems. The ability to customize the shape and size of flexible PCBs facilitates integration into diverse industrial equipment.