Can flex PCBs be used in flexible printed

A flex PCB is a type of printed circuit board that is designed to be flexible. They are often used in wearable devices like fitness trackers or health monitors for people to keep track of their heart rate, blood pressure, calories burned and steps taken. They can also be found in critical safety systems in vehicles like airbag deployment units where the ability to bend without breaking is crucial. In fact, a flex circuit is the backbone behind many automotive components like sensors and engine control units that are subject to high temperatures and vibrations under the hood.

A flex pcb is created by sandwiching layers of copper and polyimide on a rigid substrate, which provides the mechanical strength for the flex. The layers are joined together using a specialized adhesive called a PSA, or pressure-sensitive adhesive. This is applied to both sides of the flex to provide a strong, reliable bond that can withstand the bending and twisting that occurs during use. The PSA can be produced using a laser cutter, for smaller volumes, or with a punch and die set for larger production runs. The exact formula of the PSA will depend on what materials the flex will be attached to and whether environmental conditions are a concern.

The copper conductor on the flex is insulates by a layer of dielectric material, and it is protected from corrosion by a surface finish. The most common surface finish is called Electroless Nickel Immersion Gold (ENIG), which provides a thin, solderable gold layer that prevents copper from oxidizing. The ENIG surface can be finished in a variety of ways depending on the flex design, manufacturing process and environmental requirements.

Can flex PCBs be used in flexible printed pressure sensors?

Copper is renowned for its work-hardening and fatigue properties, especially if it is being repeatedly bent and flexed. One way to minimize this risk is to use a higher-grade foil that has been rolled and annealed. This increases the ductility of the copper to allow it to stretch and compress longer before fatigue cracking is initiated.

Adding additional thickness to the copper can also improve its durability. It’s also important to design the traces and connectors on your flex PCB for maximum reliability, avoiding stress points that are more susceptible to delamination. Sierra Circuits recommends the use of anchors on flex circuits and the use of teardrops, which provide a more gradual transition between wide traces and narrow connections with plated through-holes or vias.

Flex PCBs are becoming increasingly popular in both consumer and industrial electronics, as the world moves towards a more mobile lifestyle. But a flex or rigid-flex PCB doesn’t just offer convenience; it can make the difference between an electronic device that works and one that fails in its intended application. Using the complete set of CAD features and automated drawing tools in Altium Designer on Altium 365, you can make sure that your next flex PCB is designed for success. Start your free trial today.