Single-sided FPC
One copper layer with the tightest bend radius and lowest construction cost.
PCB technology / Flexible circuits
Flexible PCB Manufacturing (FPC)
Flexible PCB manufacturing treats the circuit as both an electrical interconnect and a mechanical part, with bend radius, cycle life, copper and assembly space designed together.
1–12 layersFlex layer range
0.1–0.6 mmFlexible thickness
3 / 3 milStandard geometry
Design-specificDynamic qualification
Engineering choices
Design from the way the circuit moves.
A flex-to-install interconnect and a lifetime hinge are different products. Bend radius, flex cycles and the rigid transition must be defined early.
Double-sided FPC
Plated through-holes and routing on both sides for mainstream interconnects.
Multilayer FPC
Up to 12 layers where flex routing and controlled impedance must coexist.
Rigid-flex
Flexible layers laminated into High-Tg FR-4 rigid sections to reduce connectors.
Technical reference
Flexible and rigid-flex process window
Mechanical use conditions affect every value in the table. Provide the bend radius, flex zone and expected cycle count with the RFQ.
FPC and rigid-flex specifications
Electrical and mechanical build capability
| Layer count | 1–12 layers |
|---|---|
| Flexible materials | PI (Kapton), PET, LCP; High-Tg FR-4 in rigid areas |
| Flexible area thickness | 0.1–0.6 mm |
| Rigid-flex overall thickness | Up to 3.2 mm |
| Copper weight | 1/3–2 oz |
| Minimum trace / spacing | 3 / 3 mil standard; 2 / 2 mil advanced |
| Dynamic flexing | Defined by bend radius, copper, stackup and qualification plan |
| Supported features | Coverlay, stiffeners, ZIF contacts, shielding layers, SMT |
| Testing | Electrical, AOI, dynamic flex and custom 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 bend area has its own layout rules.
Dynamic flex uses thinner copper and a controlled bend geometry. Plated holes, abrupt trace-width changes and stiffener edges should stay away from the active flex zone.
- Route traces perpendicular to the bend axis
- Keep vias and plated holes outside the active flex zone
- Select copper weight against current and cycle-life requirements
- Control coverlay openings and stiffener transitions
- Use dedicated carriers when assembling components onto FPC
PI (Kapton)PETLCPAdhesiveless laminateCoverlayFR-4 stiffenerSteel stiffenerShielding filmZIF contacts
Engineering review
Review bend zones, copper direction and coverlay before release.
Validate bend radius, trace direction, plated-hole keepouts, stiffener transitions and assembly support against the flex duty.
Bend radius against layer count and copper weight
Static versus dynamic flex duty
Trace direction and geometry through bend zones
Coverlay opening and stiffener transition placement
Panelization and material-yield planning
Connector contact finish and mechanical drawing
Practical fit
Where flexible circuits create value
Use these examples as a starting point. The board construction still follows the product’s electrical, mechanical and qualification requirements.
Wearables
Folded assemblies with tight space and weight limits.
Camera and display modules
Hinges, sliders and compact connection paths.
Medical devices
Probes, portable diagnostics and shaped interconnects.
Automotive modules
Instrument clusters, cameras and sensor interconnects.
Industrial robotics
Continuous-motion applications requiring dynamic flex review.
Aerospace electronics
Harness reduction where weight and packaging matter.
Frequently asked questions
Flexible PCB manufacturing FAQ
Use these answers to prepare the mechanical and fabrication information required for flexible PCB review.
How many layers can a flexible PCB have?
Flexible and rigid-flex constructions support 1–12 layers. Most moving flex zones remain lower layer count to preserve bend performance.
How is flex-cycle life confirmed?
Cycle life is defined from the bend radius, copper weight, layer count, trace direction and mechanical envelope, then confirmed through the agreed qualification plan.
What is the standard trace width and spacing?
The standard flex process window is 3/3 mil. Advanced 2/2 mil geometry is available after material and flex-duty review.
Can components be assembled onto FPC?
Yes. Component areas normally use stiffeners and dedicated assembly carriers. Placement, support and bend transitions are checked during DFM review.
Related PCB pages
Compare related PCB technologies and manufacturing services.
Compare flexible PCB with rigid, HDI and rigid-flex routes before fixing the mechanical package.
PCB technology
Rigid PCB (FR4)
Rigid PCB manufacturing provides a stable platform for fixed mechanical assemblies, from single-sided circuits to controlled-impedance multilayer boards.PCB technologyHDI PCB
HDI PCB manufacturing supports fine-pitch escape routing and compact board geometry through laser microvias, sequential lamination and a reliability-focused via structure.Manufacturing servicePCB Capabilities
PCB manufacturing capabilities vary by material, copper weight, layer count, via structure and finished thickness. Use the applicable process window rather than combining isolated maximum values.Manufacturing servicePCB DFM Review Service
PCB DFM review identifies fabrication, assembly and file-package risks before tooling or production release, with findings tied to the intended manufacturing process.Have a board in mind? Let’s define the right build path.
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