Flexible PCBs for High-Temperature Applications
TechnologyFlexible PCBs for High-Temperature
Every piece of electronics we own is outfitted with printed circuit boards (PCBs). These laminated structures are comprised of conductive insulated layers that serve two important functions: hosting components such as resistors, capacitors and microcontrollers in designated areas on the outer layer and providing reliable electrical connections between those component terminals and conductive pads. PCBs are available in rigid and flexible designs, with the latter enabling designers to build circuits that can conform to unique form factors.
A flex circuit’s ability to bend is determined by its construction techniques and the materials used in its layers. A flex PCB’s bending radius depends on the thickness of its substrate material and conductive layers, as well as how much pressure it can bear without damage or performance degradation. The material selection process must be optimized to maintain flexibility, as well as proper lamination and etching processes that define the circuit pattern without compromising durability.
High-density interconnect (HDI) flex circuits are ideal for high-temperature applications because they allow designers to achieve more efficient layouts, constructions and designs. These specialized circuits are also more resilient than rigid-flexible pcb board and can handle a wide range of temperature conditions.
Flexible PCBs for High-Temperature Applications
The defining feature of a flexible PCB is its curved conductive material traces, which allow it to conform to a variety of form factors. They are commonly used in a wide range of industries, such as the automotive and aerospace sectors. This is because they can accommodate complex electronic devices that require a significant amount of space and offer improved thermal performance.
In addition to their dimensional stability, flex circuits are also more resistant to corrosion and environmental stress. They can also support higher voltages than rigid PCBs and withstand vibrations, making them ideal for aerospace applications. However, the use of a flexible PCB in a harsh environment can cause the copper to weaken and damage the surrounding layers.
To prevent this from happening, it’s crucial to keep the area around a bend free of discontinuities, such as vias, cut-outs and slits. This will minimize stress and cracks that may cause failures.
Using a kapton-based adhesive to bond the flex substrate is a good idea because it has comprehensive temperature resistance qualities. Similarly, using a polyimide-based solder mask helps maintain the integrity of the conductive material and improves adhesion.
Another way to increase the reliability of a flexible PCB is to use stiffeners that will ensure the proper positioning of components on the flex substrate. It is important to use these stiffeners because they will reduce the amount of moisture that a flex circuit absorbs during assembly and the subsequent deterioration of solder joints. The stiffeners should be placed on both sides of the flex substrate to provide a mechanical support for the components, as well as to reduce the risk of damage to the conductive traces when the flex circuit bends.