Rigid PCB vs Flex PCB: What Is The Difference?

The most prominent difference between a flex PCB and a Rigid PCB can be easily deduced from their respective names: A Rigid PCB is not flexible, whereas a flex PCB can be shaped or bent to fit into a given system. Flex circuits when correctly designed can be flexed also for several cycles repeatedly with no failure. The increased flexibility of flex PCBs comes typically at a greater cost, however, they are important for applications that required limited space, such as medical devices, consumer electronics, automotive and space applications

Rigid PCBs are common, especially as a result of their lower cost relative to flex PCBs. In traditional electronics like consumer electronics with a greater availability of space, manufacturers can be economical by making use of Rigid PCBs. However, flex PCBs are starting to take a larger part of the market share from non-flexible or rigid PCBs as a result of their adaptability and among several advantages like:

1. Flexibility: Flex PCBs can be easily twisted, bent, and even folded to fit into the end or finished application. This gives the manufacturer the flexibility of having the circuitry fitted into the end device, instead of the endpoint device being designed around the circuitry. For instance, flex circuits are perfect for wearable devices, foldable mobile phones, and cameras. Rigid PCBs are hard and don’t offer such flexibility required in flex circuits applications.
2. Connectivity: Flex circuits allow a better connectivity between various electronic components, circuit boards, and user interfaces in the packaging of electronics. Flex PCBs can also create connectivity in applications (dynamic flexible applications) where the flex circuit is required to flex continually over the device’s life cycle. These types of flex circuits are widely used in laptops PCs, display connectivity, and foldable electronics.
3. Minimal Weight: Circuit boards with minimal weight produce an end product that is lighter. In present-day electronics market, this is essential because small, light-weighted devices are preferable to heavier electronic devices by electronics designers and consumers. This feature makes flex circuits to be perfect for drones and unmanned vehicles.
4. Durability: Although rigid Printed circuit boards are generally stronger and thicker, flex printed circuit boards absorb vibrations and shocks better and effectively compared to rigid printed circuit boards. This makes flex PCBs more reliable with a long-term shelf life and functionality. And are extensively used in missile guidance systems, satellites, weapons, medical electronics, and various applications that require great environmental viability.
5. Heat Resistant: Rigid printed circuit boards are likely to be damaged from heat, radiation, or chemicals; however, flex printed circuit boards are more resistant to heat and other damaging environmental conditions. This is the reason why flex PCBs are currently and widely used in automotive electronics.
6. Manufacturing Process: Flex PCBs have flex circuit overlay and are manufactured using a process known as cover lay to protect the flex PCBs circuitry (from external or apparent damage)rather than using a solder mask. Flex PCBs are generally made using Polyimide. The sheet of Polyimide has covered heat adhesives for total protection. The adhesives fill every gap on the PCB which produces a smooth flow.
7. Strength of Material: The thickness and strength of rigid printed circuit boards come typically from glass. This makes rigid PCBs to be reinforced. Flex PCBs don’t provide a similar level of material strength, but instead make use of a base material (e.g. Polyimide) that is more flexible.
8. Protection: Flex PCB uses circuit overlay for protection, while rigid PCB uses smolder mask for protection.