Reducing Costs in Electronic Product Manufacturing through Flexible Assembly Techniques
In the world of electronics, the use of Rigid-Flex PCBs (Printed Circuit Boards) is growing in popularity due to their numerous benefits. These versatile boards combine the rigidity of traditional PCBs with the flexibility of flex circuits, making them ideal for a wide range of applications.
Rigid-Flex PCBs are constructed using unreinforced substrates made up of polyimide dielectric film cladded with rolled copper. Flex sections, the flexible parts of these boards, are typically multi-layer circuits, offering 360-degree bendability, superior resistance to vibrations, compact and lightweight design, and the ability to be warped or contorted without breakage.
One of the key advantages of Rigid-Flex PCBs is their reduced susceptibility to assembly errors. This is largely due to a streamlined and standardized manufacturing process. Hole to copper clearance must be at least 10 mils in Rigid-Flex PCBs, and vias must be placed at least 50 mils away from the edge of the rigid area to ensure a smooth fabrication process.
Traces on different layers should be staggered vertically, not placed atop each other, to increase ribbon flexibility in flex areas. Annular rings should be as large as possible in flex-only regions to reduce the risk of peeling. These design considerations contribute to the overall reliability of the boards and help reduce manufacturing issues that add costs.
Minimizing the number of layers in a Rigid-Flex PCB can also reduce the number of prepregs required to fabricate the PCB, easing out the PCB fabrication process and reducing the overall manufacturing cost. No flow prepregs are critical components in Rigid-Flex manufacturing, preventing the flow of epoxy resin onto the flexible sections of the PCB.
Common strategies to further minimize costs in Rigid-Flex PCB designs include optimizing material use, design for manufacturability, and early collaboration with manufacturers. Using standard material thicknesses and copper weights reduces custom material expenses, while optimizing panel layouts minimizes material waste. Reducing the number and complexity of vias (e.g., larger vias instead of microvias where possible) lowers drilling costs, and designing for testability with accessible test points can decrease testing time and cost.
Efficient panelization to maximize material utilization also helps lower per-unit costs. Early DFM (Design for Manufacturability) reviews and close collaboration with manufacturers enable design adjustments that simplify fabrication processes, avoid rework, and leverage manufacturing capabilities for cost savings. Using manufacturer-provided inspection and imaging services can further avoid upfront capital expenditure on equipment.
Using rigid board laminates to achieve the overall thickness can also help reduce the manufacturing cost of a Rigid-Flex PCB. It's important to note that variations in the CTE (Coefficient of Thermal Expansion) among the flex/rigid prepregs would require a careful balance of thicknesses, especially for impedance control in flex designs.
A single Rigid-Flex PCB with multiple rigid sections can replace an assembly of multiple rigid PCBs within a product, leading to direct cost savings from reduced Bill of Materials and inventory. Assembly costs for Rigid-Flex PCBs are much lower than those for traditional wiring harnesses. Having all flexible arms ending in a rigid section also reduces the overall cost of Rigid-Flex PCB design.
Rigid-Flex PCBs permit better airflow and heat dissipation than many other PCBs, making them ideal for applications where heat management is crucial. They are also preferred in satellite and aerospace applications due to the PCB material used in flex sections being reliably etched.
In conclusion, Rigid-Flex PCBs offer numerous benefits in terms of manufacturing efficiency, cost savings, and performance. By understanding the design considerations and strategies for cost minimization, manufacturers and designers can leverage these versatile boards to create innovative and cost-effective solutions.
References: [1] Designing Rigid-Flex PCBs: A Complete Guide. (n.d.). Retrieved from https://www.pcbweb.com/resources/designing-rigid-flex-pcbs-a-complete-guide/
[2] Rigid-Flex PCB Design and Manufacturing. (n.d.). Retrieved from https://www.xpcb.com/rigid-flex-pcb-design-and-manufacturing/
[3] Rigid-Flex PCBs: Design Rules, Cost Reduction Strategies, and Applications. (n.d.). Retrieved from https://www.pcbway.com/library/articles/rigid-flex-pcbs-design-rules-cost-reduction-strategies-and-applications/
[4] PCB Design for Manufacturing: A Guide for Cost Reduction. (n.d.). Retrieved from https://www.pcbguide.com/pcb-design-for-manufacturing-a-guide-for-cost-reduction/
- To optimize the fabrication process and ensure controlled impedance in Rigid-Flex PCBs, it's essential to maintain sufficient hole to copper clearance and place vias a safe distance from rigid areas.
- Rigid-Flex PCB technology, with its cost-minimizing strategies and superior performance, allows for the creation of innovative and cost-effective solutions in various applications, contributing to the growth in its popularity.
