Single flex layer
A simple flexible interconnect between rigid sections where routing density and shielding needs are limited.
PCB technology / Integrated flex-rigid construction
Rigid-Flex PCB Manufacturing
Rigid-flex PCB manufacturing combines fixed component areas and flexible interconnects in one laminated board to reduce connectors and control mechanical transitions.
2–12 layersConstruction range
PI + FR-4Material system
3 / 3 milStandard geometry
Build-specificElectrical test plan
Engineering choices
Treat every rigid-to-flex transition as a reliability zone.
Rigid-flex success depends on how materials, copper, coverlay and mechanical restraint meet at each transition—not only on the routing inside the rigid areas.
Double-sided flex
Two copper layers provide additional routing while keeping the flexible section relatively thin.
Multilayer rigid-flex
Multiple flexible and rigid layers support higher routing density, controlled impedance and compact packaging.
Static or dynamic duty
A flex-to-install fold and a repeated-motion hinge require different copper, bend radius and qualification plans.
Technical reference
Rigid-flex process window
Layer count alone does not define feasibility. The complete rigid stackup, flexible thickness, bend geometry and transition details are evaluated together.
Rigid-flex PCB specifications
Electrical and mechanical construction reference
| Total layer count | 2–12 layers |
|---|---|
| Rigid materials | FR-4 and High-Tg FR-4 |
| Flexible materials | Polyimide (PI), adhesiveless copper-clad laminate |
| Flexible area thickness | 0.1–0.6 mm, construction dependent |
| Copper weight | 1/3–2 oz in flexible areas |
| Minimum trace / spacing | 3 / 3 mil standard; 2 / 2 mil advanced |
| Supported features | Coverlay, stiffeners, shielding film, controlled impedance |
| Surface finish | ENIG or ENEPIG; connector finishes by drawing |
| Testing | Electrical test, AOI and application-specific flex testing as specified |
Capability values are design-dependent. Material, copper weight, layer count, via structure, finished thickness and surface finish can change the achievable combination.
Design context
The flex section replaces a harness, not the mechanical drawing.
The finished outline, bend direction, installed radius and keep-out zones must be defined with the enclosure. Bookbinder allowances may be needed when multiple flex layers bend together.
- Keep plated holes and abrupt copper changes away from bend and transition zones
- Define the installed bend radius and whether flexing occurs once or repeatedly
- Use teardrops, curved routing and gradual width changes through stressed areas
- Align coverlay openings, stiffeners and rigid-section edges with assembly support
- Review layer-length compensation when multiple flexible layers bend as a group
PolyimideAdhesiveless laminateCoverlayStiffenerBookbinderBend radiusShielding filmENIGENEPIG
Engineering review
Review rigid-to-flex transitions before production release.
Confirm bend zones, transition geometry, coverlay, stiffeners, via placement and assembly support across the complete rigid-flex outline.
Rigid and flexible stackups against the finished mechanical envelope
Bend radius, flex duty and copper grain direction
Rigid-to-flex transition geometry and keep-out distance
Coverlay, stiffener and shielding termination locations
Via placement, annular ring and copper balance in rigid areas
Panelization, assembly support and final electrical test strategy
Practical fit
Where rigid-flex removes interconnect complexity
Use these examples as a starting point. The board construction still follows the product’s electrical, mechanical and qualification requirements.
Medical devices
Compact instruments, probes and portable equipment with shaped internal connections.
Aerospace electronics
Weight-sensitive assemblies where connector and harness reduction matters.
Camera systems
Folded optical, display and sensor modules with controlled packaging.
Automotive modules
Cameras, sensing assemblies and controls built around constrained enclosures.
Industrial instruments
Moving or folded internal assemblies that need a defined interconnect path.
Wearable products
Compact, lightweight electronics using both supported component zones and flexible routing.
Frequently asked questions
Rigid-flex PCB manufacturing FAQ
These answers cover the construction, transition and reliability questions that shape a rigid-flex build.
What is the difference between flex PCB and rigid-flex PCB?
A flexible PCB remains flexible across most or all of its construction. A rigid-flex PCB permanently laminates flexible layers into rigid board sections, creating one integrated interconnect rather than separate boards joined by connectors.
How many layers can a rigid-flex PCB have?
The published process window supports 2–12 layers. The usable number of flexible layers depends on bend duty, thickness, copper weight and the mechanical design.
Can rigid-flex PCB support controlled impedance?
Yes. Controlled impedance is available when the material system, dielectric thickness, copper geometry and reference layers are defined across the intended signal path.
What mechanical information should I send?
Provide the finished outline, rigid and flexible zone boundaries, bend direction, installed bend radius, expected cycle count and any enclosure or assembly keep-out requirements.
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