flexible PCB boards
Often found in handheld electronics, mobile phones and tablets, or vehicles, flexible printed circuit boards (PCBs) are designed to bend and fold. Using the right materials, they can endure vibrations and even shocks while still allowing for signal transmission. For more demanding applications, rigid-flex PCBs are available and provide additional durability and flexibility.
The base material used to manufacture a rigid PCB is a woven fiberglass impregnated with epoxy resin. It’s this cured epoxy that gives rigid PCBs their stiffness and structural integrity. But despite their rigidity, they can also absorb vibrations, making them ideal for use in harsh environments.
To make a flexible pcb board, manufacturers start with a dielectric substrate. Common dielectric films include PI and PET, as well as thin flexible-epoxy-and-glass-fiber cores. They then add a copper layer to the substrate, which can be etched to create electrical traces.
Can flexible PCB boards be used in underwater applications
For conductors, flex PCBs can use either copper foil or conductive coatings. Conductor foil has a better electrical performance but doesn’t offer the same bending capabilities as a flexible circuit board. Therefore, it’s important to understand the pros and cons of each option to choose the best material for your flex circuit.
If you’re building a flexible PCB for a specific environment, your fabricator may have to laminate stiffeners onto it. PI or Polyester film is the most common stiffener material, with a thickness of up to 125mm (5mil). Glass fiber, however, offers greater rigidity and is a popular choice for flex-to-rigid-board joins and interfaces.
In order to maintain conductor integrity and protect the conductive layers on a flex PCB, it’s important to add a coverlay. A common coverlay is made of Polyimide, which works in the same way that solder mask does on a rigid PCB. It helps to reduce noise, improve signal timing and offers insulation strength.
Flexible PCB boards, also known as flex PCBs, represent a revolutionary leap in electronic interconnect technology. These marvels of engineering are transforming the landscape of electronics manufacturing, offering unparalleled flexibility, reliability, and compactness for a wide range of applications.
At their core, flexible PCB boards are built on a flexible substrate material, typically polyimide or polyester, which allows them to bend, twist, and conform to various shapes and contours. This flexibility opens up a world of possibilities for design engineers, enabling the creation of electronics that can fit into tight spaces, withstand mechanical stress, and even be integrated into wearable or foldable devices.
To ensure the quality of a flex circuit board, skilled experts carry out a variety of inspection processes. They begin with a visual examination to look for contaminants and scratches before checking that the number of conductive layers matches the design specifications. After that, they can apply the appropriate finishing materials. For example, tin finishing is good for protecting pads during the insertion and soldering of components, while soft gold covering is suitable for use when the board will be exposed to cameras and other sensors.