We offer multi-material stiffeners laminated with thermal-curing adhesive films or pressure-sensitive 3M tapes:
FR-4 Stiffeners: Used beneath surface-mount (SMT) component areas and manual through-hole soldering zones to prevent mechanical stress on solder joints during board flexing.
Polyimide (PI) Stiffeners: Used to build up the exact insertion thickness at ZIF connector finger contacts (e.g., meeting standard 0.30 mm ± 0.03 mm insertion specifications).
Stainless Steel (304) & Aluminum Stiffeners: Applied where extreme mechanical rigidity, flatness, grounding, or heat dissipation is required in compact spaces.

Traditional copper plane shielding significantly increases board stiffness and reduces flex endurance. To maintain high flexibility while ensuring signal integrity, XinshunPCB integrates ultra-thin electromagnetic interference (EMI) shielding films (such as Tatsuta or Toyochem films) or printable conductive silver paste layers. These specialized films connect to ground via conductive micro-dots, offering > 50 dB shielding effectiveness across 10 MHz to 10 GHz frequencies while keeping the overall flex profile ultra-thin and supple.

We support multiple surface finishes tailored to flexible assemblies:
Electroless Nickel Immersion Gold (ENIG): Standard choice (2–3 µin Au over 120–240 µin Ni) providing excellent planarity for fine-pitch SMT components and long shelf life.
Electrolytic Hard Gold: Applied specifically on connector contact fingers (ZIF/Gold fingers) with thickness ranging from 10 µin to 30 µin over 100–200 µin nickel, ensuring maximum wear resistance over repeated insertion/withdrawal cycles.
Immersion Silver (IAg) & Immersion Tin (ISn): Cost-effective, lead-free options offering superior surface flatness and low insertion loss for high-speed signal paths.

All flexible circuits are manufactured and inspected in strict accordance with IPC-6013 Class 2 or Class 3 standards. Our testing protocol includes:
100% Electrical Netlist Testing: High-speed flying probe testing verifying continuity and absence of micro-shorts down to low-resistance thresholds.
Automated Optical Inspection (AOI): Inline inspection checking conductor line widths, spacing, and coverlay alignment accuracy.
Mechanical & Thermal Reliability Testing: Dynamic bending fatigue endurance tests (evaluating 100,000+ continuous cycles), thermal stress solder float testing (288°C, 10 seconds), and microsection inspection to verify plated through-hole (PTH) barrel copper thickness (≥ 20–25 µm).