In today’s fast-paced electronics industry, engineers face growing pressure to create devices that are smaller, smarter, and more reliable. Whether it’s a next-gen drone, a medical implant, or a rugged military system, space and performance go hand in hand. That’s where double-sided rigid-flex PCBs come into play. These advanced circuit boards blend the flexibility of flex circuits with the durability of rigid boards—on both sides—making them ideal for complex, compact applications. But what exactly are they, how are they built, and what should you expect in terms of cost in 2025? Let’s dive into this complete beginner’s guide.
1. Introduction: Why Double-Sided Rigid-Flex PCBs Matter in 2025
The global electronics market is shifting rapidly toward miniaturization and multifunctional design. Devices like wearable health monitors, aerospace modules, and smart automotive dashboards require intricate circuit layouts in limited spaces. Double-sided rigid-flex PCBs are emerging as the go-to solution, offering high reliability, space efficiency, and enhanced design flexibility—especially in harsh environments or moving assemblies.
2. What Is a Double-Sided Rigid-Flex PCB?
A double-sided rigid-flex PCB is a type of circuit board that combines two flexible layers—each with copper traces on both sides—with one or more rigid layers. This allows components to be mounted on both sides of the flex sections while connecting seamlessly to the rigid parts. Unlike single-sided versions, the double-sided design provides denser routing, better signal integrity, and improved mechanical strength.
3. Core Structure and Layer Composition
Double-sided rigid-flex PCBs typically include:
- Flexible polyimide (PI) layers with copper traces on both sides
- Rigid FR-4 layers to support critical components
- Adhesives and coverlays for insulation and protection
- Vias (through-hole or microvia) to connect different layers
A common stack-up might include 6–8 layers total, with multiple flex and rigid zones integrated into a unified board.
4. How It Works: Electrical Pathways and Interconnection
Copper traces route signals through both sides of the flexible section and into the rigid portions using plated through holes. The interconnection design can accommodate:
- Via-in-pad for BGA components
- Blind/buried vias for multi-layer transitions
- Controlled impedance lines for high-speed signals
This enables seamless integration between rigid zones and flex sections, ensuring signal integrity and structural resilience.
5. Manufacturing Process Overview
Creating a double-sided rigid-flex PCB involves:
- Material preparation (flex + rigid + copper laminates)
- Drilling and via plating
- Imaging and etching copper circuits on both sides of flex layers
- Lamination of rigid and flex sections
- Coverlay application and surface finish (ENIG, OSP, etc.)
- Electrical testing and quality control inspections
Due to complexity, manufacturers must follow IPC-6013 and IPC-A-600 Class 2/3 standards.
6. Key Advantages of Double-Sided Rigid-Flex PCBs
- Compact Design: Save space by folding the PCB inside enclosures
- Enhanced Reliability: Fewer connectors mean fewer failure points
- Dynamic Flexibility: Ideal for moving parts or vibrations
- Improved Signal Performance: Shorter routing improves EMI control
These features make them essential in applications where performance, space, and mechanical integrity are non-negotiable.
7. Common Applications Across Industries
Double-sided rigid-flex PCBs are widely used in:
- Aerospace avionics modules
- Medical diagnostic devices and implants
- Wearables like fitness trackers and smartwatches
- Automotive ADAS systems and infotainment units
Their ability to combine form and function in one board reduces assembly time and increases design freedom.
8. Typical Price Range in 2025
The cost of double-sided rigid-flex PCBs varies by complexity, quantity, and materials:
- Prototype (1–10 pcs): $150–$300 per piece
- Small-to-medium production (50–200 pcs): $40–$80 per piece
- Large volume (>1,000 pcs): $15–$35 per piece
Key pricing factors:
- Number of layers and vias
- Surface finish (ENIG is more expensive than HASL)
- Custom stack-up and impedance requirements
- Testing and certification needs
9. Challenges and Design Considerations
When designing a double-sided rigid-flex PCB, engineers must account for:
- Bending radius to prevent stress fractures
- Thermal expansion differences between materials
- Controlled impedance for signal reliability
- Clearance and pad design for flexible zones
Early collaboration with your PCB supplier can help mitigate costly design mistakes.
10. How to Choose the Right Manufacturer
Look for manufacturers who offer:
- ISO and UL certifications
- Experience with rigid-flex designs
- In-house DFM support
- Flexible prototyping and quick turnaround
- Custom stack-up engineering
Not every PCB shop can handle the complexity of double-sided rigid-flex builds—expertise matters.
11. Why Choose KingSunPCB for Double-Sided Rigid-Flex Boards
At KingSunPCB, we specialize in high-reliability rigid-flex PCB solutions. With over 15 years of experience and advanced production lines in Shenzhen, we offer:
- Full support for double-sided flex-rigid designs
- 6–20 layer capability with HDI options
- UL, RoHS, ISO9001, and IATF16949 compliance
- Free DFM review and custom stack-up suggestions
- Competitive pricing starting from $35 per board in medium volumes
Our clients include global OEMs in the aerospace, medical, and industrial sectors.
12. Conclusion: Is a Double-Sided Rigid-Flex PCB Right for Your Project?
If your design demands high reliability, space efficiency, and mechanical flexibility, a double-sided rigid-flex PCB is likely the ideal solution. While the initial cost is higher than standard PCBs, the long-term benefits in performance, durability, and assembly simplification often outweigh the investment. Partner with an experienced manufacturer like KingSunPCB to ensure your next project is both future-ready and cost-effective.