benefits of rigid flex PCBs
Rigid flex circuits offer the stability of rigid PCBs with flexible sections that allow for the expansion and contraction that occurs in many electronics. This hybrid design creates a more reliable platform capable of surviving higher levels of stress and rapid movement in industrial settings where equipment requires frequent use over long periods of time. This combination of rigid and flexible features also increases component density for smaller, more sophisticated electronic devices.
While the benefits of rigid flex circuits are compelling, this technology can present some unique challenges when it comes to PCB design. Matching your design considerations to the manufacturing process and product application will help you avoid these challenges, and ensure your finished design is as high-quality as possible.
The primary difference between a traditional rigid board and a rigid-flex board is the materials used for each segment of the platform. Using the right materials for both rigid and flexible segments of your board will help you to ensure that all parts of your design will perform correctly under the most stressful environmental conditions. The choice of materials will also affect the thermal expansion and contraction rates of your final board, and can impact how well it handles temperature changes.
Rigid Flex Circuits – benefits of rigid flex PCBs
In rigid-flex boards, the flexible segments are typically surrounded by low flow prepreg (preparation resin) to protect them from damage during the lamination process. This pre-lam is then bonded to the rigid section of your design using high-speed pressure-sensitive adhesives. Rigid-flex boards may also include stiffeners along the flex areas, to reduce bending forces on their components.
A major advantage of the rigid-flex design is avoiding the need for extra connectors and cables to interconnect each component in your device. This can save on assembly costs, speeding up production and making the device more aesthetically pleasing.
Another advantage is the flexibility of the flex-rigid PCB, which can be designed with ultra-thin constructions that squeeze PCBs into tight spaces rigid PCBs simply can’t fit into. These ultra-thin 1 or 2 layer flex designs provide the flexability required in applications like medical imaging equipment, military missile guidance systems, wearable electronics and vehicle infotainment.
The rigid-flex PCB can be designed with a variety of surface finishes, including hard and soft gold. These surfaces require additional steps and cost to fabricate, but they can also improve the board’s durability and reliability in harsh or demanding environments. It is important to choose the best surface finish for your needs, and to understand how the final product will be assembled, to determine the most appropriate material.
Achieving the performance characteristics of your rigid-flex PCB will require a careful analysis of all of its components and layout rules. For instance, proper selection of a bend radius for the flex-rigid portion of your design is critical to prevent signal integrity issues and mechanical failure. Also, ensuring that signals transition properly between the rigid and flex segments will also help to minimize noise and interference. To address these challenges, it is crucial to work closely with your fab house at the beginning of the design process to develop a solution that meets your requirements.