Flexible Circuit Boards Are A Different Species

25 September 2022
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Flex PCB boards combine durability and longevity with efficiency and functionality - while also being affordable to manufacturers. It is no wonder that engineers are pivoting to flex PCBs for powering everyday applications.

A major challenge for manufacturers is building products that are robust enough to survive harsh environments where frequent vibration, excessive temperature, and exposure to chemicals is commonplace.

Additionally, it is imperative to keep the circuit design process error-free so that the assembly process is simple and pain-free for staff. Prototyping circuit design is also crucial to the quality of a product, and the process needs to be flexible enough to reach the market in time. Flexible printed circuit boards provide a slew of advantages in all the above areas, allowing them to be used in various applications, including automotive parts, consumer-grade electronics, and medical devices.

Take a look at any electronic devices near you, including mobile phones and laptops. You will probably notice that these devices have undergone significant design changes over time, mostly getting smaller with time through smart innovations.

Flexible circuit boards are a different species - in this sense - because they have pushed forward the revolution of technology and ushered in a new era of innovation. Designers have the creative freedom to make their circuits as functional and durable as possible, all within the parameters of the finished device.

Let’s take a look at why flex circuits are such a game-changer when it comes to electronics and why they offer so many advantages compared to other PCBs.

Understanding a Flex PCB

As you can probably infer from the name, flex PCBs are circuits that happen to be ‘flexible’ with high levels of bendability. They comprise of thin substrates that manage to have very high levels of tensile strength and physical flexibility. By contrast, a rigid PCB will shatter if forced to bend or flex beyond a certain threshold.

This flexibility allows flex PCBs to be shaped into various three-dimensional shapes for use in all kinds of applications, from wearable technology and minuscule devices (such as hearing aids) to smartphones and diagnostic tools.

Flexible PCBs utilize materials that are only a few microns thick, yet are durable enough to be reliably etched. This quality makes them more useful than rigid PCBs in various applications. Another key advantage is that flex PCBs do not need conventional ribbon connectors and traditional wiring harnesses, in certain contexts.

Their flexibility allows the boards to be routed at steep angles within the very rigid confines of a device such as a smartphone or a wearable watch, while providing a high degree of conductor density.

This simply isn’t possible with rigid PCBs that often make use of ribbon cables. The flexibility of flex PCBs opens up unlimited prospects in terms of physical design, including:

360 degree bendability
Resistance to frequent vibrations
Lightweight design that allows the final product to be extremely lightweight
Can withstand all kinds of disruptions in harsh environments, including exposure to excessive temperatures and harsh chemicals
Can use small and flexible caves that occupy less space than wires
Can be warped into different shapes without breaking or compromising functionality

Easy and Simple Flex PCB Manufacturing Process

Flexible circuits are widely used by manufacturers because they permit better heat dissipation and airflow compared to other PCBs. Since they require fewer components and interconnections, the assembly cost is also much lower compared to traditional wiring harnesses. This also translates into fewer assembly errors because the manufacturing process is more repeatable, and therefore, standardized.

This means that the process can be automated without requiring manual input, which cannot be said about many wiring harnesses.

Manufacturers prefer to work with flex PCBs when working on complicated electronic systems. They are ideal for use within the aerospace, medical, and automotive industry, as they are more durable, versatile, and flexible, compared to their rigid counterparts. Compact, thinner products are a major reason why flex PCBs are so useful.

Why Switch Over to Flex PCBs

Flex PCBs provide several mechanical advantages over conventional wiring harnesses in various applications.

The best part is that flex circuits can be formed into various complex shapes with branches to other connectors. This would not be possible with conventional ribbon cables. Furthermore, flex PCBs can work with rigid boards without bringing in those tall and bulky connectors that flat cables typically require. Perhaps more importantly, flex circuits have a superior conductor density that exceeds that of ribbon cables.

Space Savings of Flex PCBs

A side-to-side comparison of flex PCBs and rigid PCBs shows that the former delivers superior results in terms of weight and space savings. Manufacturers can reduce the weight of a product by up to 75% or even more by switching over to flex PCBs.

This is because flex PCBs are made using extremely thin substrates because of the polyimide or polyester material. Some films can be as thin as 12 to 120 microns thick. Conductive material can be reliably etched on flex circuits and meet the design requirements of the board. This is often followed by the application of a coverlay to protect the layers from dirt, damage, and moisture.

Another reason why flex PCBs offer superior design is the replacement of ribbon connectors and wiring harnesses that were used to link different boards - for example, to connect different units in an automobile. This has led to several benefits to the manufacturer including economies of scale and standardization along with a lower cost of production because flex PCBs require fewer interconnections and components.

The resulting space, weight, and cost savings of flex PCB boards allow them to be produced at an industrial scale without sacrificing quality and functionality. By switching over to flex PCBs, users can notice that the cost of connections goes down by as much as 70% compared to traditional wiring harnesses. This reduction of cost translates into affordability and consistent quality that often arises due to human errors.

All the above qualities make flex PCBs an entirely different species compared to rigid PCBs. If you have any questions about flex circuit board design, feel free to contact Hemeixin PCB here.