/Custom Flexible PCB Solutions/
Flex PCB
Flex PCBs enable you to design compact, three-dimensional layouts that improve reliability while reducing system size and weight.
We specialize in single-sided, double-sided, multilayer flex PCBs, flex with stiffeners, and rigid-flex PCBs. It can meet demanding requirements for miniaturization, dynamic bending, signal integrity, and mechanical durability.
Flex PCB Manufacturer.
We are a professional Flex PCB manufacturer and Flex PCB assembly provider in China. We always deliver high-quality flexible printed circuit boards engineered for reliability, durability, and space-saving designs.
Our Flex PCB solutions support today’s most demanding electronics, from consumer devices to automotive, medical, aerospace, and industrial applications.
By combining advanced polyimide materials, fine-line imaging, impedance control, and strict quality control, we help you replace bulky wiring and rigid interconnects with lightweight, flexible, and highly reliable circuits.
Our manufacturing capacity is designed to support engineering prototypes, pilot runs, and volume production, while ensuring consistent electrical and mechanical performance.
Precision Fabrication
- Minimum trace/space: 3 / 3 mil
- Minimum laser drill: 0.1 mm
- Tight dimensional tolerances
Advanced Surface Finishes
- ENIG, OSP, Immersion Silver, Immersion Tin, Hard Gold
- Selective surface finishes available
100% Electrical Testing
- All Flex PCBs undergo AOI and flying probe testing, with optional ICT, FCT, and impedance verification to ensure compliance with design specifications.
Feature Flex PCB.
PCBSAIL provides a complete range of Flex PCB solutions, tailored to different performance, cost, and mechanical requirements.
Flex PCB We Offer.
Single-Sided Flex PCB
Single-sided flex PCBs feature one copper layer laminated onto a flexible substrate, typically polyimide.
- Ultra-thin and lightweight
- Simple structure and low cost
- One-time or static bending designs
Double-Sided Flex PCB
Double-sided flex PCBs have copper layers on both sides, interconnected with plated through-holes or microvias.
- Higher routing density
- Better power and signal separation
- Maintains flexibility with moderate complexity
Multilayer Flex PCB
Multilayer flex PCBs contain three or more conductive layers with internal power and ground planes.
- Blind and buried microvias
- Excellent EMI control
- High-speed and RF compatibility
Flex PCB with Stiffeners
Stiffeners provide localized rigidity for connectors and components while preserving flexibility elsewhere.
- FR-4
- Polyimide (PI)
- PET
- Stainless steel
- Aluminum
Rigid-Flex PCB
Rigid-flex PCBs combine rigid PCB sections and flexible interconnections into a single structure.
- Eliminates cables and connectors
- Integrated rigid and flex stack-ups
- Complex 3D assembly capability
| Item | Unit | Flex PCB |
| Max. Layers | L | 16 |
| Min. Finished Board Thickness | mm | 0.04 |
| Max. Size | mm | 500 × 2200 |
| Min. Laser Drill Hole | mm | 0.025 |
| Min. Mechanical Drill Hole | mm | 0.1 |
| Min. Line Width / Spacing | mm | 0.035 / 0.035 |
| Min. Annular Ring (Single / Double Side) | mm | 0.075 |
| Min. Annular Ring (Multilayer Inner Layer) | mm | 0.1 |
| Min. Annular Ring (Multilayer Outer Layer) | mm | 0.1 |
| Min. Coverlay Bridge | mm | 0.1 |
| Min. Solder Mask Opening | mm | 0.15 |
| Min. Coverlay Opening | mm | 0.30 × 0.30 |
| Min. BGA Pitch | mm | 0.45 |
| Single-ended Impedance Tolerance | % | ±7 |
| Base Material Type | / | Polyimide, LCP, PET |
| Base Material Brands | / | Shengyi, ITEQ, Taiflex, Newflex, Nikko, Panasonic, DuPont, Jiujiang |
| Stiffener Types | / | FR4, PI, PET, Steel, Aluminum, PSA, Nylon |
| Surface Finish | / | ENIG, ENEPIG, OSP, Electroplated Gold, Electroplated Gold + ENIG, Electroplated Gold + OSP, Immersion Silver, Immersion Tin, Electroplated Tin |
| Flex + HDI | / | 2+N+2 (Mass production) |
Flex PCB Materials
Selecting the correct substrate material is critical for electrical performance, flexibility, and long-term reliability. PCBSAIL supports a wide range of flex PCB materials from global and domestic brands.
Polyimide (PI)
Standard flexible circuit material with excellent thermal stability and mechanical strength.
- Temperature Range: −65 °C to 260 °C
- Dielectric Constant: 3.4–3.5
- Applications: Standard flex circuits, industrial electronics, medical devices
Polyester (PET)
A cost-effective flexible material for low-temperature consumer applications.
- Temperature Range: −40 °C to 105 °C
- Dielectric Constant: ~3.3
- Applications: Consumer electronics, disposable devices
Polyethylene Naphthalate
Enhanced polyester with better heat resistance and mechanical properties.
- Temperature Range: −50 °C to 155 °C
- Dielectric Constant: ~3.2
- Applications: Automotive electronics, industrial controls
Liquid Crystal Polymer (LCP)
A high-performance flex material for RF and high-frequency designs.
- Temperature Range: −200 °C to 240 °C
- Dielectric Constant: 2.9–3.2
- Applications: RF, microwave, antenna modules
Flex PCB Feature
Our flexible printed circuit boards are engineered for durability, signal integrity, and space efficiency. It makes them ideal for compact and high-density applications.
Exceptional Flexibility
Flex PCBs are built on thin polyimide or adhesiveless substrates that allow the circuit to bend, fold, or twist.
Tight Bend Radius Capability
Optimized copper thickness, rolled-annealed copper foil, and controlled stack-up design enable tight bend radii while maintaining long flex life.
Ultra-Thin Construction
With finished thicknesses as low as 0.05 mm, Flex PCBs significantly reduce overall system weight and volume
Controlled Impedance Routing
Our Flex PCBs with controlled single-ended and differential impedance, achieving tolerances as tight as ±3 Ω for high-speed digital, RF, and sensor applications.
Support for Fine-Line & HDI Designs
Flex PCBs support 3 mil / 3 mil trace and space, microvias, and fine-pitch components, enabling high-density layouts in limited spaces.
Flex PCB Manufacturing
Our Flex PCB manufacturing process is executed under strict IPC standards and controlled cleanroom conditions to ensure dimensional accuracy, electrical reliability, and long-term mechanical durability.
Each build follows a tightly controlled, multi-stage workflow designed to support fine-line routing, controlled impedance, and high flex-cycle performance.
Material Cutting
High-quality polyimide copper-clad laminates are precision-cut to panel size. Material thickness, copper weight, and grain direction are verified to ensure stable flex performance and consistent bend characteristics.
Mechanical
Via and hole structures are formed using mechanical drilling or UV/CO₂ laser drilling, depending on hole size and design requirements.
- Laser vias down to 0.1 mm
- Controlled hole wall quality for reliable plating
- Optimized for HDI and multilayer flex structures
Copper Electroplating
Electroless and electrolytic copper plating are applied to build uniform copper thickness within vias and on circuit traces, ensuring strong electrical continuity and mechanical reliability.
Dry Film Lamination
Photosensitive dry film is laminated onto the copper surface under controlled pressure and temperature, preparing the panel for precise circuit imaging.
Imaging & UV Exposure
Circuit patterns are transferred using high-resolution phototools and UV exposure systems. This step defines trace geometry, impedance-critical features, and fine-pitch structures.
Pattern Plating
Unexposed photoresist is developed away, followed by selective copper and tin plating on circuit features to reinforce traces and pads before etching.
Etching & Resist Stripping
Unwanted copper is chemically etched to form the final circuit pattern. Remaining photoresist and plating resist layers are stripped, leaving clean and accurate conductor geometries.
Surface Finishing
Surface finishes are applied to protect exposed copper and ensure solderability and contact reliability:
- OSP
- ENIG (Electroless Nickel Immersion Gold)
- Immersion Silver
Selective finishes such as ENIG + OSP are available for mixed-performance zones.
Coverlay Application
Polyimide coverlay films are precisely aligned and laminated to protect flexible traces while maintaining controlled openings for pads, connectors, and solder areas.
Pressing
Multi-layer flex or rigid-flex structures are thermally laminated under controlled heat and pressure to ensure layer integrity, adhesion strength, and dimensional stability.
Electrical Testing
All boards undergo comprehensive electrical inspection:
- AOI (Automated Optical Inspection) for pattern accuracy
- Flying probe testing for opens, shorts, and continuity
- Impedance verification for controlled-impedance designs
Final Inspection
Final inspections confirm mechanical dimensions, surface quality, and workmanship compliance with IPC standards. Boards are vacuum-sealed and packaged using ESD-safe materials to prevent damage during shipment.
| Item | Unit | Flex PCB |
| Max. Layers | L | 16 |
| Min. Finished Board Thickness | mm | 0.04 |
| Max. Size | mm | 500 × 2200 |
| Min. Laser Drill Hole | mm | 0.025 |
| Min. Mechanical Drill Hole | mm | 0.1 |
| Min. Line Width / Spacing | mm | 0.035 / 0.035 |
| Min. Annular Ring (Single / Double Side) | mm | 0.075 |
| Min. Annular Ring (Multilayer Inner Layer) | mm | 0.1 |
| Min. Annular Ring (Multilayer Outer Layer) | mm | 0.1 |
| Min. Coverlay Bridge | mm | 0.1 |
| Min. Solder Mask Opening | mm | 0.15 |
| Min. Coverlay Opening | mm | 0.30 × 0.30 |
| Min. BGA Pitch | mm | 0.45 |
| Single-ended Impedance Tolerance | % | ±7 |
| Base Material Type | / | Polyimide, LCP, PET |
| Base Material Brands | / | Shengyi, ITEQ, Taiflex, Newflex, Nikko, Panasonic, DuPont, Jiujiang |
| Stiffener Types | / | FR4, PI, PET, Steel, Aluminum, PSA, Nylon |
| Surface Finish | / | ENIG, ENEPIG, OSP, Electroplated Gold, Electroplated Gold + ENIG, Electroplated Gold + OSP, Immersion Silver, Immersion Tin, Electroplated Tin |
| Flex + HDI | / | 2+N+2 (Mass production) |
Flex PCB Applications
Flexible Printed Circuit Boards (Flex PCBs) are widely used in modern electronics where space efficiency, mechanical flexibility, and high reliability are critical. By replacing rigid boards, connectors, and wire harnesses, Flex PCBs enable compact designs, improved durability, and simplified system integration.
PCBSAIL manufactures high-reliability Flex PCBs for both static and dynamic applications, supporting prototypes through high-volume production.
Electronics
Flex PCBs are essential in compact, lightweight consumer devices that require complex internal routing.
Typical applications include:
- Smartphones and tablets
- Wearable devices (smartwatches, fitness trackers)
- Cameras and image sensors
- Foldable and hinge-based products
Automotive Electronics
Automotive systems demand Flex PCBs that withstand vibration, temperature extremes, and long service life.
Typical applications include:
- Instrument clusters and dashboards
- ADAS cameras and sensors
- Battery management systems (BMS)
- Interior lighting and control modules
Automation
In industrial environments, Flex PCBs provide durability and design flexibility for complex electromechanical systems.
Typical applications include:
- Robotics and motion control systems
- Industrial sensors and actuators
- Human-machine interfaces (HMI)
- Control and monitoring equipment
Medical Devices
In industrial environments, Flex PCBs provide durability and design flexibility for complex electromechanical systems.
Typical applications include:
- Robotics and motion control systems
- Industrial sensors and actuators
- Human-machine interfaces (HMI)
- Control and monitoring equipment
Telecommunication
Flex PCBs support high-speed signal transmission and compact module design.
Typical applications include:
- RF modules and antennas
- High-speed data interconnects
- 5G communication equipment
- Optical transceivers
Fast Quotation
Our professional sales and engineering teams provide fast PCB quotes and technical support. Simply send us your Gerber files, BOM, and assembly drawings, and we will respond promptly with a competitive solution.
- Gushu Tangxi Second Industrial Zone, Shenzhen
- +86 755 2335 0814
- +86 135 1078 8094
- sales@pcbasail.com
FAQ About Flex PCB
1. What Is a Flex PCB?
A Flex PCB (Flexible Printed Circuit Board) is a circuit board built on flexible base materials such as polyimide, allowing it to bend, fold, or twist without damaging the electrical connections. Flex PCBs are widely used in compact, lightweight, and high-reliability electronic products.
2. What Is a Rigid-Flex PCB?
A Rigid-Flex PCB combines rigid PCB sections with flexible circuit layers in a single structure. It eliminates connectors between rigid boards and flex cables, improving reliability and reducing assembly complexity. Rigid-Flex PCBs are commonly used in aerospace, medical, and high-end industrial applications.
3. What Is The Difference Between Flex PCB and Rigid PCB?
Structural Comparison
| Feature | Flex PCB | Rigid PCB |
|---|---|---|
| Base Material | Polyimide, PET, LCP | FR-4 (glass epoxy) |
| Mechanical Behavior | Bendable, foldable | Rigid, inflexible |
| Thickness | Ultra-thin (≥0.05 mm) | Thicker (≥0.8 mm typical) |
| Shape Options | Custom, 3D layouts | Flat, fixed shape |
Mechanical Performance
| Aspect | Flex PCB | Rigid PCB |
|---|---|---|
| Vibration Resistance | Excellent | Moderate |
| Shock Resistance | High | Limited |
| Dynamic Movement | Supported | Not supported |
| Connector Dependency | Low | High |
Flex PCBs excel in environments with movement, vibration, or mechanical stress, where rigid boards are prone to failure.
Electrical Performance
| Aspect | Flex PCB | Rigid PCB |
|---|---|---|
| Signal Path Length | Shorter | Longer |
| EMI Control | Improved (fewer interconnects) | Standard |
| Controlled Impedance | Excellent (±3 Ω achievable) | Excellent |
| High-Speed Support | Yes | Yes |
While both technologies support high-speed designs, Flex PCBs reduce discontinuities caused by connectors and cables.
Assembly & System Integration
| Aspect | Flex PCB | Rigid PCB |
|---|---|---|
| Assembly Complexity | Lower | Higher |
| Cable & Harness Use | Minimal or none | Often required |
| System Weight | Lower | Higher |
| Reliability | Higher (fewer failure points) | Lower in complex systems |
Cost Consideration
| Factor | Flex PCB | Rigid PCB |
|---|---|---|
| Board Fabrication Cost | Higher | Lower |
| Assembly Cost | Lower | Higher |
| Total System Cost | Often lower | Often higher |
| Maintenance Cost | Lower | Higher |
Flex PCBs frequently provide better overall cost efficiency at the system level, especially in compact or high-reliability designs.
4. What Materials Are Used In Flex Pcbs?
Most Flex PCBs use:
- Polyimide (PI) for high temperature and mechanical stability
- Rolled-annealed copper for dynamic flex areas
- Adhesive or adhesiveless copper-clad laminates
Optional materials include PET or LCP for specific cost or high-frequency requirements.
5. What Is The Minimum Trace Width And Spacing For Flex Pcbs?
Typical manufacturing capability:
- Minimum trace/space: 3 mil / 3 mil
- Advanced HDI designs: 3 mil spacing
Actual limits depend on layer count, copper weight, and impedance requirements.
6. Can Flex PCB Support Controlled Impedance?
Yes. Flex PCBs can be manufactured with controlled impedance for high-speed and RF applications.
- Single-ended impedance tolerance: ±5 Ω
- Advanced designs: ±3 Ω
Impedance is verified using TDR testing.
7. Are Flex PCBs Suitable For Dynamic Bending?
Yes. When designed correctly, Flex PCBs can support repeated or continuous bending.
Key design factors include:
- Bend radius
- Copper type (rolled-annealed)
- Layer stack-up
- Avoidance of vias in bend areas
Dynamic flex designs are commonly used in hinges, robotics, and camera modules.
8. What Surface Finishes Are Available For Flex PCBs?
Common surface finishes include:
- ENIG (Electroless Nickel Immersion Gold)
- OSP
- Immersion Silver
- Lead-free HASL
Selective finishes such as ENIG + OSP are available for mixed-function areas.
Dynamic flex designs are commonly used in hinges, robotics, and camera modules.
9. Can Stiffeners Be Added To Flex Pcbs?
Common surface finishes include:
- ENIG (Electroless Nickel Immersion Gold)
- OSP
- Immersion Silver
- Lead-free HASL
Selective finishes such as ENIG + OSP are available for mixed-function areas.
Dynamic flex designs are commonly used in hinges, robotics, and camera modules.
10. Do You Offer Flex PCB Assembly?
Yes. We provide turnkey Flex PCB assembly, including:
- SMT and through-hole assembly
- Fine-pitch BGA and QFP support
- Component sourcing
- Functional and electrical testing
11. How Many Layers Can A Flex PCB Have?
Standard Flex PCBs typically support 1–6 layers. Advanced designs can reach 7–10 layers, depending on material selection, stack-up design, and application requirements.