A free working reference for flex and rigid-flex circuits. Estimate assembly cost, check minimum bend radius against IPC rules, compare constructions, and shortlist a manufacturer — built for PCB designers, hardware engineers, and buyers.
// flex + rigid-flex assembly
Flex PCB assembly is the process of placing and soldering components onto a flexible printed circuit — a conductor pattern etched on thin polyimide film — or onto the flex sections of a rigid-flex board.
Because the substrate bends and polyimide absorbs moisture, flex assembly needs steps rigid boards don't: a pre-bake to drive off moisture before reflow, carriers or fixtures to hold the limp panel flat through the oven, stiffeners (FR4, polyimide, or steel) under connectors and component clusters, and bend zones kept clear of pads and heavy copper.
Done well, the payoff is a three-dimensional interconnect that folds into the product — replacing cables, board-to-board connectors, and wiring harnesses with a single shaped circuit that's thinner, lighter, and more reliable.
Two live instruments to size a project in seconds. Estimates are indicative — for a precise figure, send your files for a flex PCB assembly quote.
Heuristic estimate covering bare-board fabrication + SMT assembly. Real pricing depends on parts cost, BGA/fine-pitch, stiffeners, testing, and finish. Get an exact quote →
Bend zones should be free of plated through-holes, vias, and component pads. Cross-hatch any ground planes in the flex region. Ask PCBSync to DFM-check your stackup →
| Parameter | Standard | Advanced | Notes |
|---|---|---|---|
| Conductor layers | 1–4 | 6–8+ | Single, double, multilayer & rigid-flex |
| Min trace / space | 0.10 / 0.10 mm | 0.05 / 0.05 mm | 4 / 2 mil at the fine end |
| Min finished via | 0.20 mm | 0.10 mm laser | Keep vias out of bend zones |
| Base copper | 0.5–1 oz | 2 oz | Rolled-annealed copper for dynamic flex |
| Polyimide core | 1–2 mil | 0.5 mil | Adhesiveless laminate for reliability |
| Coverlay opening | ±0.13 mm | ±0.05 mm laser | Laser-cut for tight registration |
| Stiffeners | FR4 / PI | Steel / Al | Under connectors & component areas |
| Assembly & inspection | SMT + AOI | + X-ray, fine-pitch BGA | To IPC-A-610 / J-STD-001 |
Capabilities vary by manufacturer. These are common industry ranges — confirm against your chosen supplier's flex datasheet.
| Attribute | Flex | Rigid | Rigid-flex |
|---|---|---|---|
| Substrate | Polyimide film | FR4 / glass-epoxy | Both, integrated |
| Bends & folds | Yes — static or dynamic | No | In flex sections only |
| Component density | Low–medium | High | High (on rigid zones) |
| Replaces cables/connectors | Yes | No | Yes |
| 3D / Z-axis packaging | Excellent | Limited | Excellent |
| Relative unit cost | Medium | Low | High |
| Best for | Thin, light, fully bendable | Dense, flat, low-cost | Reliable 3D assemblies |
Flex and rigid-flex win wherever space, weight, reliability, or a folded 3D shape matter more than raw component density.
Hearables, patches, hearing aids, endoscopes and implantables that must conform to the body and survive sterilization.
// thin double-sided flex + stiffenersCamera modules, folding hinges, display drivers and battery interconnects packed into millimeters of space.
// dynamic flex, fine-pitchBattery management, ADAS sensors, lighting and instrument clusters that endure heat, vibration and 15-year lifecycles.
// rigid-flex, 2 oz copperAvionics, satellites and missiles where weight savings and vibration resistance are mission-critical.
// multilayer rigid-flex, high-relCompact sensors, robotics joints and control panels that route signals around tight, moving mechanics.
// flex jumpers + connectorsLED strips, OLED/LCD driver tails and backlight assemblies that bend behind the panel.
// single-layer flex, long-railFlex is unforgiving — a strong rigid-board shop is not automatically a strong flex shop. Tick the criteria a prospective supplier meets to gauge fit.
PCBSync meets every criterion on this list — IPC-qualified flex fabrication and assembly under one roof, with DFM built into every quote.
Check PCBSync against your list →Send your Gerbers and BOM to PCBSync for a DFM review and an exact quote on flex and rigid-flex assembly — prototype through volume.
