Customer Background

The customer is a tech innovator specializing in next-generation smart wearables.Their flagship product, a smart ring, integrates health monitoring, sleep tracking, and NFC functionality.Due to the extremely confined internal space of the ring, the customer demanded industry-leading integration and bending reliability for the PCB

Project Background

The project involves a core control module requiring a 6-layer layout on an ultra-small flexible substrate.As the FPC must be installed within a circular ring casing, it undergoes multiple tight-radius bends and carries high-precision SMD components.

Project Challenges

• Extreme Space Constraints: The original through-hole design risked breakout on micro-PADs and occupied excessive interlayer space, making routing impossible.

• Complex Stack-up Requirements: The original drilling layers were restricted by manufacturing capabilities and could not be processed directly.

• Assembly Precision Risks: During double-sided SMT assembly, FPC expansion and shrinkage could compromise soldering accuracy.

• Mechanical Protection: Original sharp-cornered outlines posed a risk of scratching the product during assembly and were suboptimal for long-term tooling.

How We Served

• Stack-up & Design Optimization: Our engineering team recommended a 1+1+2+1+1 Any-layer structure, deconstructing the original through-holes into multi-layer blind and stacked via designs.

• Process Refinement: We optimized all drill diameters to 0.075 mm, effectively resolving routing bottlenecks and breakout risks.

• Mechanical Stress Protection: We suggested adding R0.2/R0.5 rounded corners to all sharp outlines to reduce scratching risks and enhance fatigue resistance.

• Proactive Technical Support: We coordinated "scaling stencils" and provided early communication on material behavior to ensure a smooth transition from sampling to mass production.

Results and Benefits

• Successful Prototyping: Precise stack-up adjustments overcame the manufacturing bottlenecks of Any-layer FPCs.

• On-time Delivery: Through rigorous production management, we met the client's urgent exhibition deadlines in early 2026.

• Enhanced Yield: By optimizing hole sizes and adding R-corners, we significantly improved assembly pass rates, laying a solid foundation for future high-volume production.