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What Are Rigid-Flex PCBs?
Hybrid circuit boards combining rigid and flexible sections for dynamic applications.
- Maintains constant bend angles during installation
- Enhanced durability in space-constrained environments
- Ideal for complex multi-layer designs
Topfast specializes in high-quality rigid-flex PCBs, with engineering expertise to meet your specific application requirements.
Why Choose Rigid-Flex PCBs
Topfast delivers high-reliability rigid-flex solutions that maximize performance in compact designs.
- Space Saving
60% smaller than traditional boards with wiring harnesses
- Design Flexibility
Bend and fold to fit complex geometries
- High Reliability
100,000+ flex cycles with no connection failures
- Durability
Withstands extreme temperatures up to 300°C
Rigid-Flexible PCB Materials
Surface Treatment Options
✔ HASL (Vertical or Horizontal)
✔ Lead-Free HASL
✔ OSP (Shikoku F2)
✔ OSP (Entek)
✔ ENIG (Electroless Nickel Immersion Gold)
✔ Immersion Silver
✔ Immersion White Tin
✔ Tin-Nickel
✔ Electrolytic Soft Gold
✔ Electrolytic Hard Gold
✔ Selective Gold
Surface Treatment Options
| Parameter | Metric Value | Imperial Value |
|---|---|---|
| Min Core Thickness | 0.051 mm | 0.002″ |
| Max Finished Copper Weight | 89 ml | 3 oz |
| Max Finished Copper Thickness | 0.009 mm | – |
| Smallest Mechanical Drill | 0.180 mm | 0.0071″ |
| Smallest Laser Drill | 0.127 mm | 0.005″ |
| Min Finished Hole Size | 0.152 mm | 0.006″ |
| Max Through Hole Aspect Ratio | 10:1 | – |
| Max Blind Via Aspect Ratio | 0.75:1 | – |
| Min Trace/Space (Rigid) | 0.089 mm | 0.0035″ |
| Min Pad Size for Test | 0.127 mm | 0.005″ |
Rigid-Flexible PCB Materials
| Material Type | Example / Subtype | Function |
|---|---|---|
| Conductors | Rolled Annealed (RA) Copper | Used in flexible circuits requiring repeated bending. It offers superior ductility, a grain structure aligned with the bend axis, and a reduced risk of micro-cracking. |
| Electro-Deposited (ED) Copper | Preferred in rigid sections and some static flex zones. Provides high conductivity and fine trace definition but lower flex fatigue performance than RA copper. | |
| Adhesives | Epoxy | Strong adhesion with low moisture absorption. Tg typically ≥135 °C. Commonly used between copper and dielectric layers in rigid zones. |
| Acrylic | High peel strength, chemical resistance, and thermal stability (Tg ~150 to 200 °C). Often selected for rigid-flex bonding interfaces. | |
| Pressure Sensitive Adhesive (PSA) | Low-temperature bonding layer is used to attach stiffeners or mount flex circuits. Limited to non-electrically active zones. | |
| Polyimide (as adhesive) | Extreme thermal resistance (>250 °C) and chemical durability. Used in aerospace-grade flexible PCB assemblies exposed to harsh environments. | |
| Adhesiveless Base Material | Polyimide is cast directly onto copper foil. Eliminates adhesive interface, improves flexibility, reduces Z-axis expansion, and enhances thermal reliability in dynamic flex circuits. | |
| Pre-preg (Resin-coated Glass) | Dielectric bonding sheet used during multilayer lamination in rigid areas. Properties depend on the resin system (Tg, flow, Dk/Df). | |
| Insulators / Dielectrics | FR-4 | Standard rigid PCB core. Tg typically 135 to 170 °C. It provides mechanical support and a routing platform for rigid flex boards. |
| Polyimide | High-flex, high-temperature material (Tg >250 °C). Used in flexible sections due to superior bend endurance and dimensional stability. | |
| CEM-1 | Cellulose-based composite alternative to FR-4. Used in cost-sensitive rigid sections with low mechanical stress. | |
| Polyester (PET) | Flexible and thermally stable (~120 to 150 °C), lower cost than polyimide. Used in basic flexible PCB assemblies. |
FAQ
✓ What certifications do your PCB factories have?
All of our products are IPC rated with ISO 14001, ISO 9001, CE, and ROHS certificates. Our products are widely used in communication, medical equipment, industrial control, power supply, consumer electronics, aerospace, and automotive industries.
✓ How many layers can your rigid-flex boards do?
Rigid zone: 4-20 layers (up to 30 layers), Flexible zone: 1-8 layers. We can also do 6-12 layers of rigid-flex combination. Designs over 16 layers require additional yield assessment (every additional 5 layers decreases yield by 8-12%).
✓ Can you copy boards and provide batch pricing?
All of our products are IPC rated with ISO 14001, ISO 9001, CE, and ROHS certificates. Our products are widely used in communication, medical equipment, industrial control, power supply, consumer electronics, aerospace, and automotive industries.
✓ How does rigid-flex PCB quoting work?
Our pricing is transparent with no hidden fees. Quotes can be made in as little as 10 minutes, depending on board complexity.
✓ Do you charge for shipping? How is it calculated?
We calculate shipping based on destination address/zip code and product weight. Customers can request shipping quotes before finalizing orders.