Every rigid-flex production panel is built and qualified in strict accordance with IPC-6013 Class 2 and Class 3 specifications. Our standard testing workflow includes:
100% Netlist Electrical Testing: Double-sided flying probe testing to verify netlist continuity and eliminate open/short risks.
Micro-Focus 3D X-Ray Inspection: Verifying registration, alignment, and void-free barrel fill on inner blind and buried microvias.
Destructive Microsectioning & Thermal Stress: Solder float testing at 288°C (10 seconds) and cross-section analysis to confirm plated through-hole (PTH) barrel copper thickness ≥ 25 µm.

The boundary between rigid and flexible sections absorbs the highest mechanical shear stress during bending. We engineer robust stress relief through multiple proven DFM rules: (1) Applying automated dispensing of flexible epoxy or polyurethane strain-relief bead fillets along the transition line; (2) Overlapping the flexible coverlay into the rigid zone by at least 1.0 mm; (3) Routing copper traces strictly perpendicular or with curved radiused bends across the transition border; and (4) Staggering adjacent conductor traces to prevent the stiffening "I-beam" effect.

We fabricate rigid-flex stackups from 2 to 20+ layers in both symmetric and asymmetric architectures. Common configurations include 1R+2F+1R (4L), 2R+2F+2R (6L), and multi-rigid islands connected by independent flexible jumpers. We also specialize in Air-Gap (unbonded multi-layer flex) constructions, where adjacent polyimide layers remain separate across the bending area to dramatically lower bending stiffness and extend dynamic cycling fatigue life.

Controlling resin squeeze-out is critical to preserving flex circuit suppleness and preventing trace cracking along the interface. We utilize specialized no-flow or low-flow prepregs (e.g., Ventec VT-47 / Shengyi S1000-2B) paired with precision CNC-milled prepreg window cutouts. During vacuum differential lamination, thermal ramp rates and multi-stage pressure curves are precisely regulated, restricting resin overflow along the flex window edge strictly to ≤ 0.1 mm (4 mil), fully conforming to IPC Class 3 criteria.