Flexible PCB Boards Can Be Mass-Produced
Printed circuit boards (PCBs) are the essential building blocks of electronic devices. They connect various components to form a functional unit that can be tested and used for various purposes. PCBs are fabricated from various materials and can be made in many different shapes and sizes to suit specific applications. They can also be laminated to rigid or flex materials. The most common material for a PCB is copper, due to its high workability and plating properties. Moreover, it is able to withstand a wide range of temperatures and vibrations. A flexible PCB is a great option for those in need of a durable, space-saving and lightweight product.
In order to build a flex PCB, it is important to select a manufacturing partner with the right experience and capabilities. You want to ensure that they have a reputation for providing fast-turn services and excellent quality products. Furthermore, you should choose a company that offers detailed fabrication drawings. These are critical to the success of your design.
The main component of a flexible pcb board is the conductor layer, which is typically made from copper foil. This conductor is either etched or electrodeposited. The latter technique provides better impedance control, but is expensive. Copper foil can be either rolled and annealed (RA) or etched and electrodeposited (ED). Both types have unique characteristics, but the RA copper is easier to handle because it has a column-like structure, making it more accessible for roughening and etch processing. The ED copper has a fish scale shape and is harder to process, but it offers superior toughness.
How Flexible PCB Boards Can Be Mass-Produced
A flex circuit may also contain stiffeners, which are additional mechanical pieces that provide support for certain areas of the board. The stiffeners can be FR4, Polyimide (PI) or metal (not mentioned what kind, but probably stainless steel). The choice of these materials will affect the manufacturing cost.
Finally, the outer surfaces of a flex circuit are protected by coverlay layers. The coverlay insulating layers can be an additional layer of PI or PET or even a photo-imageable solder mask ink. Alternatively, adhesive-less processes are available, where the coverlay is essentially printed on the flex PCB section with a photolithographic process.
The etching and plating of a flex circuit is very different from that of a rigid PCB, which makes it important to understand the differences between them. The key difference is that flex circuits are prone to movement and contraction during manufacture. As such, it’s important to maintain a consistent drill-to-copper distance of at least 8 mils. In addition, it is important to consider whether a panel plating method or pad-only-plating (button plating) is best for your application. The former allows for a more uniform copper thickness and improves etch yields in small traces. The latter, on the other hand, requires more specialized and expensive equipment to implement.