Flex Circuit Boards
The thickness of a flex circuit board is an important factor in its overall functionality. If it is too thin, the flexible circuit may shatter under stress. However, if the thickness is too high, it may not be able to bend sufficiently for its intended use. In order to determine the appropriate thickness, designers can look at several different factors.
Conductors: Conductors are essential to a flex circuit and allow electrical current to flow freely. The most common conductor material is copper, but other materials can also be used. These materials are often coated in an insulator to protect them from oxidation and damage. The insulator can be made of several different materials, but it is most commonly made from a polyimide film.
An insulator is required to separate the conductors from each other. It also helps to strengthen the flex circuit and provide a stable base. The insulator is usually made of a non-conductive epoxy or acrylic, though some flex circuits are adhesive less and therefore do not need an insulator. In addition to providing support, insulators can also be used as a solder mask to ensure the proper alignment of surface mount components.
A flexible circuit is more resilient than a traditional rigid PCB, but that does not mean it is immune to damage or stress. It is important to keep in mind the amount of stress that the flex circuit will be subjected to during its life cycle and to plan accordingly. A good way to do this is to calculate the amount of bending that will occur.
How Thin Can Flex Circuit Boards Be?
The bend radius is the minimum distance that the flex circuit can flex without suffering any damage. This is important to identify in the design phase to avoid bending the circuit at an angle that could cause damage. Bends that are too severe can lead to I-beaming, which is the buckling of the traces due to a high amount of pressure. In order to minimize this, designers should stagger the traces and make sure that they have adequate clearance between them.
It is also recommended to use rounded edges in the areas of the flex circuit that are expected to be bended, as this will increase the tear resistance. In addition, it is a good idea to avoid using solid copper for the traces that will be in the bending area, as this will reduce its flexibility. Instead, it is a better option to use hatched copper, as this will be more flexible than a solid polygon.
In addition to the above considerations, it is crucial to choose the right manufacturing partner. A quality flex circuit board manufacturer will be able to produce quick-turn prototypes and will utilize the highest quality materials for the best results. They should also be able to offer a variety of coatings and finishes.
Another important consideration is the testing and quality assurance process. A reputable flex circuit board manufacturer will perform rigorous tests on all their products to ensure that they meet industry standards and are up to your specifications.
