Construction of Rigid Flex Circuits

Rigid flex circuits are hybrid printed circuit boards that incorporate flexible substrates inside rigid PCB materials. They are a great solution for complex electronic devices that require both flexibility and stability. They are also used in many industrial applications like automotive and heavy equipment. Rigid-flex circuits reduce the number of solder joints and board-to-board connectors needed to connect multiple PCBs, thus lowering overall production costs for large-scale production runs.

When designing a flex or rigid flex circuits, it’s important to consider the operating environment. The flex/rigid-flex circuit’s layout and design will need to take into account the mechanical requirements of the application, as well as the reliability requirements for the entire system.

To increase the reliability of a flex or rigid-flex circuit, consider the operating temperature, the mechanical load, and how much stress the flex/rigid-flex circuit will be exposed to. In addition, it’s a good idea to consult with the PCBWay team to ensure that the conductors and routing will be able to handle any physical stresses that may occur during the device’s operation.

Explaining the Construction of Rigid Flex Circuits

The construction of a flex or rigid-flex PCB typically involves a copper core with layers of insulators. The most common insulators are FR-4 or polyimide. A layer of FR-4 or polyimide protects the copper from damage during the fabrication process, and a surface finish (which can be nickel, gold, or electroless nickel) keeps the copper traces clean and solderable. In order to increase the strength of the flex or rigid-flex PCB, some manufacturers add a rigid substrate or stiffener layer.

A rigid flex circuit can be constructed with different layer counts and technologies, but the higher the layer count, the more expensive it will be. Other factors that can affect cost include the etch yield and material thickness, as well as blind and buried vias.

Using thinner copper traces will increase the flex-resistance of the circuit, but it’s best to avoid using wide traces on bend areas as they can easily cause damage during bending. Also, consider adding pad fillets to the flex-areas to improve etched yield and material strength.

In the case of a rigid-flex circuit, the encapsulated construction eliminates exposed interconnections, which increases resistance to environmental threats. It also helps reduce the amount of signal interference, as the critical signals routed on inner flex layers are isolated from external noise sources by ground planes. Finally, the rigid-flex circuit’s flexibility allows for thermal vias to draw heat away from hot components, reducing the operating temperature and improving reliability. During the PCBWay quoting process, we take the specifications and materials of the rigid-flex circuit into consideration to generate an accurate quote that meets your exact needs.