Flexible PCB, also known as flex circuit, is made of flexible polyimide substrate. It can bend, fold and twist freely, saving internal space for compact electronic devices. Single-layer flexible PCB is our common option for low-cost and space-limited projects.
A high-quality single-layer flexible printed circuit (FPC) consists of a single conductive circuit layer; its structure, from top to bottom, is: coverlay → copper foil circuit layer → polyimide (PI) substrate → bottom coverlay/stiffener.
Specifications
| Structure | Common Materials and Specifications | Explanation |
|---|---|---|
| Substrate layer | PI Film 12.5μm / 25μm / 50μm | Bearing layer PET/PEN is cheap but has poor heat resistance and flexibility |
| Conductor layer | Rolled copper RA, electrolytic copper ED; 1/3oz (12μm) to 2oz (70μm) | RA copper has a high flexural life and is used for dynamic bending. ED copper is cheap and is used for static purposes |
| Adhesive layer | Acrylic / Epoxy / Polyester Adhesive 12.5–25 μm | Adhesive-free (cast) type offers superior flexibility. |
| Covering film | PI film + adhesive, 12.5-25μm | Line protection and insulation |
| Reinforcement (optional) | PI, FR4, Steel/Aluminum Stiffeners, PSA (Pressure-Sensitive Adhesive) | For rigid support of connectors and pad areas. |
Performance characteristics
- Flexibility: Single-layer structures feature a distinct neutral axis for bending and minimal interlayer slippage, making them the optimal FPC configuration for flex life. A combination of RA copper, PI, and an adhesive-free structure allows for tens of thousands of dynamic bending cycles.
- Lightweight and thin: The total thickness can range from 0.05 to 0.12 mm—far thinner than rigid boards—making it suitable for space-constrained assemblies.
- Temperature resistance: PI withstands long-term exposure to -65–150°C and soldering heat of 260°C for 10 seconds; PET withstands only up to ~105°C.
- Electrical properties: High insulation resistance, low dielectric constant (εr ≈ 3.3–3.5), and low dielectric loss; suitable for low-loss applications.
- Can be assembled three-dimensionally: bending, winding, three-dimensional wiring, replacing wire harnesses.
Applicable scenarios
| Field | Typical applications |
|---|---|
| Consumer electronics | Mobile phone battery FPC, camera module, button/fingerprint, headphone/speaker ribbon cable |
| Medical care | Patient monitors, defibrillators, hearing aids, wearable sensors |
| Automobile | Automotive LED lighting modules, sensors, ECUs / connectors and wiring harnesses |
| Industry | Printer printheads, hard drive ribbon cables, robot joints, motors |
| Wearables / IoT | Watches, smart bands, smart tags |
Volectronics Tech Co., Ltd has been supplying high-quality PCB and PCBA to clients worldwide since 2017 — from prototype to mass production.
We offer a diverse selection of PCB material, including FR4, Rogers, Metal based, TU, Isola, PI, and other high-frequency material, providing a wide range of options to meet your specific requirements.
We offer Aluminum PCBs, Flex PCBs and all types of circuit boards for sale, every order, regardless of size, receives the utmost attention to detail throughout the entire process to ensure all customer expectations are met.
