typical range of layer counts for rigid flex pcbs
Many of today’s most popular electronic devices feature rigid PCBs along with flex circuitry for mechanical stability and reliability. These include laptop and desktop computers, tablet and smartphone devices, flat-screen TVs and monitors, cameras and other high-tech equipment. Rigid flex PCBs are also increasingly found in medical and military devices, industrial equipment and wearable electronics. Rigid flex circuits provide the flexibility of a flexible printed circuit board with the stability of a rigid one, which helps to address space constraints and other physical challenges in these applications.
The typical flex-rigid multilayer PCB has two rigid sections separated by four flex layers. The number of flex layers can vary from two to eight, but higher flex layer counts can increase cost. rigid flex pcb can be made with either single or double-sided traces, depending on the application. Single-sided traces are etched on the top side of the flex section, while double-sided traces are etched on both sides of the flex section. Rigid flex traces can also be configured with S curves, which reduce the likelihood of traces cracking under stress.
A flexible printed circuit board requires special fabrication and lamination techniques to produce. The flex layers must be separated from the prepregs that bond the layers of standard multilayer PCBs, and the flex-rigid layer stackup must be carefully designed to avoid introducing stress or shorts. The choice of flex-rigid materials is also important, as exotic and specialty options carry additional costs. Additionally, plating options like selective and immersion silver add to the overall manufacturing expense, and surface finishes like carbon ink require extra steps.
What is the typical range of layer counts for rigid flex pcbs?
High-reliability rigid flex circuit boards typically require more complex processes than standard multilayer PCBs, which drives up the cost. Additionally, tight tolerances on tracing features and alignment can impact the overall manufacturing efficiency of a flex-rigid PCB. Finally, the use of rigid flex circuits often requires a more rigorous testing and quality assurance program than standard PCBs to ensure quality and reliability.
Regardless of the complexity, cost and benefits, a rigid-flex PCB can be an excellent solution for your design. However, before submitting your PCB design to a rigid flex pcb manufacturer, ask about the factory’s experience with the specific type of board you need. Make sure that the factory can manufacture your design with the appropriate layer count, material requirements and other features.
In addition, look for factories that offer online tools to calculate and order rigid-flex PCBs. These tools can help to save you time and money in the early phases of your design process.
LeitOn’s online tool enables you to create a 2R+2F rigid-flex PCB construction with just a few clicks. This is a common rigid-flex configuration that includes two flex layers, positioned internally or externally. Contact us to learn more about our specialized capabilities for rigid-flex PCBs and how we can help you to design, order and build your next project.