What is Rigid-Flex PCB?
Rigid-Flex PCB is a hybrid circuit board that combines the best attributes of both rigid (FR-4) and flexible (Polyimide) substrates into a single, integrated unit.
Unlike a simple assembly where a flex cable is plugged into a rigid board, a Rigid-Flex PCB is permanently laminated together. The circuits extend continuously from the rigid section through the flexible section via Plated Through Holes (PTH). This creates a seamless 3D interconnect system that eliminates the need for bulky connectors and wire harnesses.
Types of Rigid-Flex PCB
At RUNHI, we engineer Rigid-Flex solutions ranging from simple to highly complex HDI structures:
- Standard Construction: Consists of a single flexible layer (or dual-sided flex) sandwiched between rigid FR-4 layers. The most common and cost-effective type.
- Multi-Layer Rigid-Flex: Features multiple layers of flexible circuitry (3+ layers) integrated within the rigid sections. Used for high-density routing in aerospace and defense.
- HDI Rigid-Flex: Incorporates High Density Interconnect technologies, such as laser-drilled microvias, blind/buried vias, and fine lines. Essential for smartphones and compact medical devices.
The Benefits of Rigid-Flex PCB
- Maximum Reliability: By eliminating connectors, cables, and solder joints (the most common points of failure), Rigid-Flex PCBs significantly improve shock and vibration resistance.
- Space & Weight Reduction: It allows for precise 3D packaging, folding into tight housings where standard boards simply cannot fit. It can reduce total product weight by up to 60%.
- Signal Integrity: Continuous copper traces offer better impedance control and lower signal loss compared to signals passing through a connector or wire harness.
- Simplified Assembly: It streamlines the supply chain and assembly process. Instead of buying and soldering multiple boards and cables, you install one single component.
Common Applications of Rigid-Flex PCB
- Medical Devices: Pacemakers, Cochlear implants, Endoscopes (where size and reliability are non-negotiable).
- Aerospace & Defense: Missile guidance systems, Satellites, "Black Box" recorders (high vibration resistance).
- Consumer Electronics: Foldable smartphones, Digital Cameras (DSLRs), True Wireless (TWS) Earbuds.
- Automotive: ABS sensors, Gearbox controls, Camera modules.
- Industrial: Robotics arms, Handheld scanners.
Why Choose RUNHI as Your Rigid-Flex Manufacturer?
- Complex Lamination Expertise: We utilize advanced "No-Flow" Prepreg and specialized vacuum lamination cycles to prevent adhesive flow onto the flexible areas, ensuring perfect flexibility.
- HDI & Via Capability: We are experts in Any-Layer HDI, laser drilling, and copper plating on mixed materials, allowing for ultra-high-density designs.
- Material Science: We use high-performance Dupont Pyralux or Panasonic flexible laminates paired with High-Tg FR-4 to ensure the board survives multiple reflow soldering cycles without failure.
- Dynamic Flex Testing: For applications requiring frequent bending (like laptop hinges), we perform rigorous bend-cycle testing to guarantee fatigue resistance.
RUNHI Technical Capabilities (Rigid-Flex)
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| High TG, FR-4 + Polyimide |
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| Green/Black/White/Red/Blue/Yellow |
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