What are Rigid-Flex Circuit Boards?

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As the name implies, a Rigid-Flex PCB is a hybrid of a Flex PCB and a Rigid PCB. The combination of the two types of boards utilises the benefits each one provides, integrating the versatility of the flexible board with the robustness of the rigid board. Rigid-flex printed circuit boards are used in more complex mechanical designs, eliminating flexible cables and wiring and replacing it with integrated circuits.



Rigid-Flex PCBs, by definition, are a combination of rigid part(s) joined by interconnecting flex areas where the flex material is used across the entire PCB area.

The rigid parts are where there is no bending requirement. Again, PTHs take connections from layer to layer as required. Rigid-flex may also employ other technologies as required eg. HDI. Unlike the cost-effective flex PCBs, Rigid-Flex PCBs can be a bit more costly due to their intricate design.

Rigid-flex PCB design can be used to eliminate or greatly reduce requirements for bulky and costly cable harnesses, in turn taking out costs and reducing assembly time. Like the pure flexible PCBs, a high volume of rigid-flex PCBs are used in aviation and space applications – and also in automotive and test equipment.
The flexible layers of a Rigid-Flex PCB are buried within the board and penetrate through the rigid sections of the PCB.


The trend to miniaturization in electronics continues. Integrated circuit board solutions are becoming more and more popular as a means of efficiently utilizing the even smaller casing volume in all three dimensions.



A rigid-flex printed circuit board is unique as the rigid part of the circuitry can be placed directly into the application. Then, the flexible section can be bent and even folded to fit around components to make another direct connection. This aspect ensures a reliable connection to parts for higher performance.



Some of the most common products that incorporate rigid-flex PCBs in their design include laptop computers, smartphones, and wearable devices due to the bending capabilities of rigid-flex.



Rigid-flex pcb boards are PCBs that have Flexible PCBs (FPC) and Rigid PCBs on the same board, which are commonly employed to save space, remove wiring assemblies and can also be welded with complex components. Combining other higher technology boards, such as HDI, as a part of its packaging, is also a common design.



Rigid Flex PCB design


The designs of Rigid Flex PCBs are a little more complex as these boards are designed in 3D, which allows the board to be folded or twisted to create the desired shape for the product. Designing a board in 3D means they can offer greater spatial efficiency and can subsequently be used in special instances where space and weight reduction may be necessary, such as in medical devices. By being able to design in three dimensions designers can twist, fold and roll the flexible board substrates to achieve their desired shape for the final application's package.



Rigid Flex PCBs are usually thinner than other boards, meaning it’s a great option for any thin or light packaging needs your products may have. With thin copper layers and adhesive-less laminates, it’s a great small, thin and light solution for your circuit design needs.



Rigid-Flex PCBs Fabrication Applications:


Rigid-Flex PCBs offer a wide array of applications, ranging from smart devices to cell phones and digital cameras. Increasingly, rigid-flex board fabrication has been used in medical devices such as pacemakers for their space and weight reduction capabilities. The same advantages for rigid-flex PCB usage can be applied to smart control systems.



In consumer products, rigid-flex doesn't just maximize space and weight but greatly improves reliability, eliminating many needs for solder joints and delicate, fragile wiring that are prone to connection issues. These are just some examples, but Rigid-Flex PCBs can be used to benefit nearly all advanced electrical applications including testing equipment, tools and automobiles.



Rigid-Flex PCB and Its Production Process


The development of FPC and PCB has spawned a new product that is called rigid-flex PCB. Therefore, rigid- flex PCB is according to the relevant process requirements and through the lamination process to combine rigid board and flex board to form a circuit board with FPC characteristics and PCB characteristics.

Because rigid-flex PCB has a variety of complex structural forms, the manufacturing process is also different. Below picture shows the regular rigid-flex PCB and an example for regular stack up design.