How PCB Flex Circuits Can Be Used in Wearable Technology

PCB Flex Circuits

In today’s ever-evolving world of technology, the possibilities are endless. The world of wearable electronics is no exception and can offer us new opportunities for innovation. However, the electronic circuits within these devices must be able to withstand the rigors of daily use and constant movement. PCB flex circuits can help achieve this by adding durability and flexibility to wearable technology.

The PCBs in many wearable devices must be flexible to allow for their natural bending and stretching. To do so, the boards must have a very thin substrate made from either polyimide or glass fiber, and then a layer stack of conductive material is added. This is then coated with a coverlay (typically PI or PET) that protects the layers from moisture, chemicals and other environmental elements.

These pcb flex can have single-sided or double-sided circuitry. Single-sided flex circuits have their copper-plated through holes on one side of the substrate, while double-sided flex circuits have their through holes on both sides of the substrate. Both types of flex circuits are available in different thicknesses, and it is important to know the flex class requirements of your design before starting fabrication.

How PCB Flex Circuits Can Be Used in Wearable Technology

One of the most important considerations for a flex circuit is its ability to resist fatigue, which can occur from repeated bending or creasing. To ensure this, the flex PCB must have a minimum bending radius to avoid stressing the materials to the point of plastic deformation or failure. This is often measured by a flex cycle number.

A flex circuit’s design must also take into account the effect of temperature on its material properties and flex life. To reduce the risk of failure due to temperature variations, the flex circuits should be engineered using accurate thermal modeling and simulation software tools. These models must include the material’s specific properties, including a minimum allowed bending radius.

It is also important to understand that the choice of copper can have a significant impact on cost for a flex circuit. While cheaper copper is fine for rigid PCBs, for a flex circuit that will be continuously bent and rolled you want to use a higher-grade Rolled Annealed (RA) copper foil. This will give the flex circuit more springiness in its z-deflection direction and be more tolerant of fatigue cracking.

Another factor that impacts cost is the addition of stiffeners to a flex circuit. Stiffeners are a small amount of rigid material placed in selected areas of the circuit to provide mechanical stability and reduce the likelihood of failure. This can be done in both flex and rigid-flex PCBs, and the type of stiffener used will depend on the application.

As you can see, planning a flex PCB is quite complex, as there are many variables to consider. It is crucial to have a trusted PCB manufacturer with the expertise to support you through every step of the process, from design to production. The team at Rocket-PCB is always here to answer any questions you may have, so don’t hesitate to contact us!