Applications 📅 November 28, 2024 ⏱ 7 min read

Understanding Flex-Rigid PCB Applications

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Flex-rigid PCBs combine the best of both worlds: the durability and component density of rigid boards with the flexibility and space-saving advantages of flex circuits. This hybrid technology is indispensable in applications where reliability and compact design are critical.

The Anatomy of a Flex-Rigid Board

A typical flex-rigid assembly consists of:

  • Rigid sections: FR-4 or high-performance laminates for component mounting
  • Flexible sections: Polyimide-based circuits that bend and fold
  • Transition zones: Controlled impedance interfaces between rigid and flex areas
  • Coverlay: Protective polyimide film over flex areas

Why Choose Flex-Rigid?

1. Space Optimization

Flex-rigid designs reduce connectors and cables by replacing multiple rigid boards with a single integrated structure. Devices can shrink 60% or more by eliminating bulky interconnects.

2. Improved Reliability

Fewer connectors mean fewer mechanical failure points — especially valuable in vibration-prone environments like aerospace or automotive systems.

3. Reduced Assembly Time

Replacing multiple boards and connectors cuts labor time, assembly steps, and potential rework.

Industry Applications

Medical Devices

Flexible sections conform to the human body, making flex-rigid ideal for pacemakers, implants, and surgical tools.

Aerospace & Defense

Navigation systems, cockpit displays, and satellite electronics rely on flex-rigid PCBs due to their durability and weight reduction.

Consumer Electronics

Smartphones, tablets, wearables, and cameras depend on flex-rigid connections for moving hinges, displays, sensors, and folding designs.

Design Considerations

Bend Radius

Minimum bend radius depends on copper thickness and material stackup. Designers must ensure the flex section is manufactured to withstand repeated bending.

Layer Stackup

Flex sections typically contain fewer layers than rigid sections. Careful stackup reduces stress at transition areas.

Strain Relief

Sharp transitions between rigid and flex areas can introduce cracking. Reinforced fillets and curved transitions help distribute stress.

Material Selection

Polyimide-based materials are standard for flex circuits. Aerospace requires thermal resistance, while medical devices require biocompatibility.

Manufacturing Best Practices at Xekera

  • IPC Class 3 manufacturing for high-reliability applications
  • Laser direct imaging for fine-feature accuracy
  • Controlled impedance routing
  • X-ray inspection of hidden vias and joints
  • Automated optical inspection for every layer

Getting Started

Whether you're creating a new flex-rigid product or optimizing an existing design, Xekera’s engineering team can review your design for manufacturability (DFM) and improve long-term reliability.

Have a Project in Mind?

Contact our team to discuss your PCB manufacturing needs and get a custom quote.

Request a Quote