Flex PCBs for Military
Unlike traditional rigid printed circuit boards (PCBs), flexible circuits can bend and flex, making them more adaptable to small or irregularly-shaped spaces, which is critical for military applications where space is limited. They are also more lightweight, reducing the overall weight of the application.
Besides flexibility, flex PCBs offer numerous other advantages such as faster assembly, better thermal management, and more. This makes them a great choice for military applications where high-speed and reliability are essential. In addition, they are more aesthetically pleasing, making them ideal for applications that require a sleek and attractive design.
The most common flex circuit pcb material is copper foil. While there are many different types of metal foil available, copper is the best option for a wide variety of applications due to its cost effectiveness, physical and electrical performance, and manufacturing ease.
Flex PCBs for Military Applications
Double-sided flex circuits have conductor layers on both sides of the board and can be constructed with or without plated through holes. They are a more expensive option than single-sided flex circuits, but they provide added strength and reliability.
To avoid stress points in your flex circuit, make sure to stagger traces and route them perpendicular to the bend line. This eliminates I-beaming, which can weaken traces and cause them to crack when bending the circuit. It’s also important to transition from thick to thin traces gradually, rather than abruptly.
In order to keep your flex circuit strong, make sure to have a drill-to-copper distance of 8 mil or more. This will help prevent the traces from being brittle during fabrication. Moreover, it will ensure that the conductors have sufficient clearance for heat expansion and contraction. This will also reduce the risk of short circuits caused by temperature fluctuations.
It’s also a good idea to use tin finishing and soft gold covering on your traces and pads. This will add extra protection to the copper surface, and it will also protect it from scratches and abrasions during assembly.
One way to strengthen a flex circuit is by adding a layer of conductive epoxy. This will prevent the traces from breaking and will also protect the circuit from corrosion. To further increase the durability of your flex circuit, you can even add a layer of adhesive tape to selected areas. This will increase the cost of your flex circuit.
Another method of strengthening a flex circuit is to add a rigid-flex connector. This is a hybrid of standard rigid PCBs and flex circuits. This type of PCB is used in aerospace and military applications that need additional support, protection from vibrations and abrasions, and high component density. Rigid-flex circuits are also ideal for medical devices that need to withstand harsh environments, such as implantable health monitoring and surgical equipment. Rigid flex circuits can also be used in avionics systems and navigation devices. They can withstand extremely high temperatures and vibrations, and they are also more resilient to environmental conditions than standard rigid PCBs.
