Flex-Rigid PCBs
Throughout the evolution of consumer electronic devices such as laptops, MP3 players and mobile phones, they’ve become increasingly compact, lightweight and durable. These innovations are possible due to the emergence of flex circuits. They enable designers to create innovative products that were not possible with rigid PCBs.
Rigid PCBs can be prone to fracture and failure when subjected to mechanical stress, especially in devices that must bend and flex. This is why flex-rigid PCBs are ideal for portable electronics that must withstand the wear and tear of everyday use. Using a flex-rigid PCB design also allows you to rethink how your product is packaged and shipped.
For example, a PDA-like device used to scan and track inventory in shipping and fulfillment warehouses needs to be small and light enough to be comfortable for workers on the floor. It also needs to be able to survive the rough handling that comes with a busy warehouse environment. A flex rigid pcb is ideal for these devices because it can be manipulated without causing damage or disrupting operations.
Flex-Rigid PCBs for Battery-Powered Devices
The technology behind a flex-rigid PCB offers a range of cost savings over traditional rigid printed circuit boards and cable assemblies. This is because a flex-rigid PCB has a lower layer count and does not require the use of multiple surface finishes, which can increase costs. A flex-rigid PCB also requires less plating, which can reduce production costs. Finally, a flex-rigid PCB can be fabricated in fewer steps than a rigid PCB, which can save you money.
A flex-rigid PCB can also help you save on labor and materials costs by eliminating the need to add solder masks, silkscreens or other finishing components. This can significantly cut your production and assembly costs. Lastly, a flex-rigid board can be fabricated with a single laminate. This can further drive down costs and lead to a smaller overall product size.
The primary differences between a rigid PCB and a flex-rigid circuit board are the structure, conductor material and adhesives used to bond the substrate and conductor layers. The substrate material is typically made of Polyimide, which can withstand extreme temperatures and has superb thermal expansion properties that prevent breakage. A flex-rigid circuit board also uses polyimide adhesives to ensure that the flexible and rigid sections of the board remain intact during the manufacturing process.
The conductor material for a flex-rigid circuit is either electro-deposited copper or rolled copper foil. Both types of copper are available in a variety of thicknesses and weights, and both offer high workability and good electrical characteristics. Choosing the correct material can be challenging, as different materials have different thermal expansion coefficients and can cause signal integrity problems during operation. The copper foils are also chemically treated to increase adhesion, enhance bond strength and protect against oxidation. Connector placement is another critical consideration for a flex-rigid board, as poorly placed connectors can lead to mechanical stress and failure. A flex-rigid PCB requires careful engineering and collaboration between your electrical and mechanical teams to ensure that all the components and traces will be able to withstand repeated bending and flexing.
