Streamlined Electronic Product Manufacturing through Rigid-Flex Techniques Lowers Production Expenses
In the world of electronics, Rigid-Flex Printed Circuit Boards (PCBs) are becoming increasingly popular due to their versatility and performance benefits. But what about the cost? Here's a look at how to design Rigid-Flex PCBs in a cost-effective manner.
Rigid-Flex PCBs, a combination of rigid and flexible technologies, offer numerous advantages such as better airflow and heat dissipation, compact and lightweight design, and superior resistance to vibrations. However, their manufacturing process can incur additional costs, particularly when mechanical support is needed for flex arms ending in a flex cable.
To keep costs down, it's recommended to follow some strategic approaches.
- Standard Materials and Copper Weights: Using standard material thicknesses and copper weights can help avoid premium pricing and reduce plating costs. Custom materials, which can add 10-20% to costs, should be avoided.
- Optimized Layout: Designing PCB dimensions to fit standard production panels can lower material waste and cost per unit.
- Simplified Vias: Prefer larger via sizes where possible, and minimise microvias, which are expensive due to the precision required in drilling.
- Streamlined Layer Stack-Up and Routing: Avoid overly tight tolerances, fine lines, and intricate impedance control where unnecessary, as these increase manufacturing difficulty and risk of defects.
- Design for Testability and Manufacturability: Including accessible test points reduces testing time and cost. Early Design for Manufacturability (DFM) consultation with the manufacturer helps identify cost-saving design adjustments.
- Consolidated Design Complexity and Production Volume: Higher volumes lower unit costs by amortizing tooling and programming expenses.
- Partnering with Efficient Manufacturers: Partnering with manufacturers offering automated testing and efficient production technologies can further reduce labour and processing costs.
A sample 4-layer Rigid-Flex stackup is shown in the article. To minimise costs, it's recommended to keep the number of layers as low as possible and to use rigid board laminates to achieve the overall thickness.
Flex sections in a Rigid-Flex PCB are built using unreinforced substrates made up of polyimide dielectric film cladded with rolled copper. Traces on different layers should be staggered vertically, not placed atop each other, to increase ribbon flexibility in flex areas.
Designing flex sections to end in a rigid section reduces the overall cost of Rigid-Flex PCB design. Annular rings should be as large as possible in flex-only regions to reduce the risk of peeling. 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.
Using Rigid-Flex PCBs can lead to direct cost savings from reduced Bill of Materials and inventory, and indirect cost savings from reduced assembly costs and improved reliability. In fact, a single Rigid-Flex PCB with multiple rigid sections can replace the entire assembly of separate Rigid PCBs within a product, reducing inventory and leading to direct cost savings.
One of the most critical components in Rigid-Flex manufacturing is no flow prepregs, which prevent the flow of epoxy resin onto the flexible sections of the PCB.
In conclusion, by optimising materials, manufacturing steps, and design complexity, it's possible to design cost-effective Rigid-Flex PCBs. These strategies address materials, process steps (material preparation, drilling, plating, testing), and design complexity to achieve significant cost savings in Rigid-Flex PCB manufacturing.
[1] Source: "Rigid-Flex Circuit Design and Manufacturing for Cost Savings" by Isola Group LLC. [2] Source: "Design Guidelines for Rigid-Flex PCBs" by Altium. [3] Source: "Rigid-Flex PCB Design and Manufacturing for Cost Savings" by TTM Technologies.
- In data-and-cloud-computing, where efficient technology is crucial, applying strategies like standard materials and copper weights, optimized layout, simplified vias, streamlined layer stack-up and routing, design for testability and manufacturability, consolidated design complexity, and production volume can help control impedance and costs in Rigid-Flex Printed Circuit Boards (PCBs) manufacturing.
- By partnering with manufacturers offering automated testing and efficient production technologies, and using no flow prepregs, designers can further leverage technology to minimize costs and ensure the successful production of Rigid-Flex PCBs in the world of electronics.
