PCB Tech - Comparison between rigid PCB and flexible PCB

The two main types of PCBs are flexible PCB circuit boards and rigid PCB boards. As the name implies, rigid PCBs are inflexible, while flexible PCBs can be easily bent or otherwise shaped to fit the specified system. Although rigid and flexible PCBs are still very popular, mainly because of their low cost, they have recently taken market share from rigid PCBs based on their versatility and other advantages that follow. Based on the following reasons, flexible boards are recommended and preferred.

1. The flexibility of flexible PCB

Unlike rigid printed circuit boards, flexible PCB are still a popular choice because they are easy to bend, fold and even crease to fit or match the end application. The ability to easily rotate is an aspect that allows designers to own the circuits that provide the equipment, rather than letting the terminal equipment be built around electronic equipment and circuit boards. Unlike rigid printed circuit boards that may not be suitable for wearable electronic devices, flexible printed circuit boards are very suitable for wearable electronic devices and medical devices, foldable mobile phones, sensors, and implants.

2. The connectivity of flexible PCB

Unlike rigid printed circuit boards, flexible printed circuit boards provide excellent connectivity between other circuit boards, user interfaces in electronic packages, and electronic components.

These are some of the reasons why many designers prefer them to rigid printed circuit boards. In addition, flexible printed circuit boards provide excellent connectivity in applications where the circuit needs to be constantly bent over the working life of the device. Therefore, flexible printed circuit boards have been widely used in foldable electronic products, laptop computers and display connections.

flexible PCB

3. Flexible PCB lightweight

In terms of weight, rigid printed circuit boards are slightly heavier than flexible printed circuit boards. A lower pressure circuit board brings a lighter final product, which is essential in the current electronic market. Electronic equipment designers and consumers prefer miniature/small, lightweight equipment. Rigid printed circuit boards are not ideal for many applications because they are a bit heavy compared to flexible printed circuit boards. Flexible circuits are suitable for drones, various medical devices, and unmanned vehicles because of their light weight.

4. Flexible PCB has good durability

Although rigid printed circuit boards are generally thicker and stronger than flexible printed circuit boards, flexible PCBs can withstand shock and vibration more effectively. In other words, in terms of durability, flexible PCBs have a certain degree of durability compared to rigid PCBs. Flexible PCBs help achieve long-term reliability, functionality, and product life. Flexible PCBs are widely used in weapons, missile guidance systems, medical electronics, satellites, and applications that require excellent environmental survivability.

5. Flexible PCB durable

Another reason designers prefer to use flexible printed circuit boards over rigid PCBs is based on the fact that flexible PCBs are highly resistant. Unlike flexible PCBs, rigid printed circuit boards are most likely to warp or be damaged due to chemicals, heat, and radiation. Flexible printed circuit boards are highly resistant to harmful environmental conditions such as extreme weather. The ability to withstand extreme weather conditions, radiation or chemicals explains the large number of applications or uses of flexible printed circuit boards in many applications such as automotive electronics.

6. Miniaturized version of existing technology

In recent years, electronic applications requiring small packages, low power consumption, and enhanced functions have proliferated. In terms of printed circuit boards, miniaturization, small size and low weight are also obvious. By using flexible printed circuit board technology, engineers can create printed circuit boards with strict size restrictions. Using flexible printed circuit boards, manufacturers can now manufacture smaller electronic and optical products and equipment. Good examples of such products and accessories include computers, mobile phones, and most medical devices. Unlike rigid printed circuit boards, flexible printed circuit boards meet the requirements of miniaturization.

7. Shock and vibration resistance

Compared with rigid printed circuit boards, flexible printed circuit boards can withstand severe shocks and vibrations. Flexible printed circuit boards are ideal for high-vibration and high-impact environments. Compared to rigid PCBs that may not perform as expected and cause equipment failure, flexible printed circuit boards are easier to survive in high-stress environments, especially when they are exposed to severe and rapid vibration.

Those who work in industries that use high-vibration instruments will find flexible printed circuit boards an ideal choice because they help offset any wear and tear caused by sustained high shocks and vibrations. If you are looking for a circuit board that can provide some of the best features in addition to being able to withstand severe vibrations, then you'd better choose a flexible printed circuit board.

8. High temperature and high density applications

In addition to the ability to withstand shock and vibration, flexible PCBs also have a large number of uses in high-temperature and high-density applications. In many cases, polyimide or similar polymer materials are used to produce flexible printed circuit boards. Compared with rigid PCB board materials, polyimide is one of the materials with better heat dissipation effect.

Flexible printed circuit boards can withstand extreme temperature conditions, which is why they are used in large numbers, especially in borehole surveying in the oil and gas industry. Being able to withstand high temperature conditions, flexible printed circuit boards provide many benefits for manufacturers. Flexible printed circuit boards are the first choice for most engineers dealing with PCB applications.

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9. Will flexible circuits replace rigid circuit boards for all applications?

There is no doubt that flexible printed circuit boards are very convenient. However, they will not completely replace rigid printed circuit boards for all other applications. Cost efficiency is a major obstacle to the implementation of exclusive flexible circuit board designs in consumer products. Rigid printed circuit boards are not expensive to manufacture and install. However, ideally, innovative products are products that incorporate flexible circuits when necessary, while using stable and reliable rigid circuit boards to reduce assembly and manufacturing costs.

Some manufacturers use hybrid rigid-flex PCBs to reduce costs. Rigid-flex PCBs are widely used in medical equipment and notebook computers, where rigid boards are connected by using ribbon-shaped flexible circuits. iPCB produces rigid and flexible printed circuit boards at very competitive prices.

About the cost of flexible PCB

In terms of cost, flexible printed circuit boards are slightly more expensive to manufacture and install than rigid printed circuit boards. Unlike rigid printed circuit boards, flexible printed circuit boards require the creation of some additional engineering files. Some flexible PCB design have Coverplays, pressure sensitive adhesives, and stiffeners. This may require engineers to manually review flexible designs and create custom programs, which is why flexible printed circuit boards are expensive compared to rigid PCBs.

Although the manufacturing and installation costs of rigid printed circuit boards are slightly lower, it is difficult to ignore the advantages of flexible printed circuit boards. Although flexible printed circuit boards are expensive, many engineers choose them because they are durable and can perform product functions as needed. However, it is worth noting that the cost usually increases as the number of layers increases. Many other factors can affect the value of PCBs. If you are interested, you can read more of our articles to understand.

The application of flexible printed circuit board is very common, and its applications are continuously developing in many industries such as medical, military, and automobiles. You will notice that flexible PCB circuit boards have many benefits. Are you buying rigid printed circuit boards or flexible printed circuit boards in the market?