The global flexible printed circuit board market was valued at USD 27.12 billion in 2025 and is projected to reach USD 88.3 billion by 2035, growing at a CAGR of 12.52% from 2026 to 2035.

Five years ago, flexible circuitry was considered a specialist alternative to standard rigid boards, used mainly where space was limited. Clearly, that positioning has shifted.

Smartphones, laptops, tablets and wearables remain the most visible drivers of that growth, but they are no longer the whole story. Automotive electrification, 5G infrastructure and the steady miniaturisation of medical devices are all pulling original equipment manufacturers (OEMs) towards flexible circuitry for products that were, until recently, built exclusively on rigid boards.

A flexible printed circuit board can now be found in places as varied as automotive instrument clusters, ventilators and defibrillators, and even implantable devices such as pacemakers and cochlear implants, where the circuit itself has to survive inside the human body.

If you’re evaluating board technology for a new product, the decision of whether to choose rigid or flexible PCBs now sits alongside questions about protection, testability and which PCB assembly services partner can deliver the finished printed circuit board assembly at the volumes you need.

What flexible circuitry changes

The headline benefit is bend radius.

A flexible printed circuit board can be folded, rolled or wrapped into shapes a rigid board could never occupy, which opens up enclosure designs that would otherwise need separate boards joined by cable assemblies. That alone removes a category of failure points; every connector and cable joint is a place where contact resistance, vibration fatigue or moisture ingress can cause problems over the life of the product.

In practice, this benefit needs to be designed deliberately rather than assumed.

IPC-2223, the industry standard governing flexible and rigid-flex board design, sets minimum bend radius ratios based on layer count and whether the bend is static, fixed once during assembly or dynamic and flexed repeatedly in use.

A single-layer flex circuit in a dynamic application typically needs a bend radius of at least ten to twenty times the material thickness; tighter radii increase stress on copper traces and shorten the life of the circuit. Getting this wrong at the design stage is one of the most common reasons flex projects fail prototype testing, so raise bend requirements with your electronics manufacturer before layout begins.

Reducing the number of separate connectors also reduces overall part count, which is part of why flex circuits are popular in sensors and compact industrial devices. Where a product needs both rigid sections for component density and flexible sections for routing, rigid-flex construction combines the two on a single continuous board, removing the connectors between separate rigid and flex assemblies altogether.

Durability and environmental resistance

Flexible circuitry can also be preferred to rigid boards in demanding sectors because it survives longer in the field. With fewer connectors and a thinner, more pliable construction, flex circuits absorb vibration with less stress transferred to solder joints and components.

Properly designed dynamic flex circuits, using rolled annealed copper rather than the electro-deposited copper found in most rigid boards, can be rated for over 200,000 bending cycles when the bend radius is sized correctly. Rolled annealed copper’s elongated grain structure gives it far greater fatigue resistance under repeated flexing than the copper used in static applications.

Flex circuits also tend to perform well across a wide temperature range and resist corrosion and moisture better than an unprotected rigid board, which is one reason they turn up so often in automotive, marine and outdoor industrial equipment.

Where a section of the circuit needs extra rigidity, such as around a connector or a heavy component, a stiffener bonded to the underside of the flex restores local strength without affecting the flexibility of the rest of the board. This is standard practice in applications subject to continuous vibration, such as off-road vehicles and construction equipment.

Where flexible circuitry saves money, and where it doesn’t

A flexible printed circuit board is not usually cheaper to manufacture than a rigid board on a like-for-like basis. The materials cost more, and the lamination presses, etch processes and handling equipment involved are more specialised.

Savings tend to show up further down the build, not at the bare board stage. Fewer cables, connectors and wire harnesses mean less labour at the printed circuit board assembly stage and fewer parts that can be sourced incorrectly or go obsolete. For products with a high connector count, this can offset the higher board cost outright.

It is also worth factoring in field maintenance: fewer connectors mean fewer potential failure points, which is essential for remote or hard-to-access installations such as subsea sensors or oil, gas and water infrastructure, where a service call is expensive.

Where a product has a low connector count to begin with, or doesn’t need the bend performance, the cost case for flex circuitry is weaker.

Protecting a flexible circuit: conformal coating, potting and encapsulation

A flexible circuit still needs protecting from moisture, dust, chemicals and thermal cycling once it leaves the bare board stage, but the protection method has to respect the flex itself.

Conformal coating is generally the better starting point for flex applications. A thin, flexible coating such as silicone or a flexible acrylic formulation adds minimal mass and moves with the substrate, protecting against humidity and condensation without restricting the bend zones. Automated conformal coating, applied through a programmable dispensing system, gives far more consistent thickness control across a flexible circuit than manual spraying.

Potting and encapsulation are still used on flex assemblies, but normally on the rigid sections only, such as a connector interface or a component cluster that needs mechanical reinforcement, never across an area designed to bend.

If your product needs both environmental sealing and bend performance in the same region, the design usually needs reworking, not a stronger compound.

Getting this right depends on the protection method being specified alongside the board layout, not bolted on once the design is finished. Discuss conformal coating and potting requirements with whoever is handling your PCB assembly services early in the design process, before the layout is finalised.

Choosing the right PCB: questions to answer before you specify a board

Before specifying flex, rigid or rigid-flex PCBs, you should consider:

• Mechanical environment. Does the product need to bend once during assembly, or repeatedly throughout its service life? The bend radius, copper type and cycle-life requirement all follow from this answer.
• Connector count. Count how many connectors and cable assemblies a rigid alternative would need. The more there are, the stronger the case for consolidating them into a single flex circuit.
• Signal requirements. High-frequency or high-speed signals may favour specific flex substrates such as liquid-crystal polymer, which behaves differently from standard polyimide. Raise this early if the product carries RF or high-speed data.
• Protection needs. Decide early whether conformal coating, localised potting, or both will be required, and check that the bend zones are accounted for upfront.
• Volume and cost. Flex tooling and material costs are higher per board; the case strengthens at higher connector counts and weakens at low volumes, so model both options against your bill of materials.
• Testability. Confirm how the printed circuit board assembly will be tested, including automatic optical inspection and any in-circuit or functional test, before the layout makes test point access difficult in flexed sections.

A good electronics manufacturer will work through this list with you because most of these decisions affect manufacturability and long-term reliability more than they affect the initial bill of materials. If your current PCB assembly services partner isn’t asking these questions, find out why.

EC Electronics: your partner for flexible and rigid printed circuit board assembly

EC Electronics is an electronics manufacturer with over 40 years of experience supporting OEMs across automotive, medical, industrial, IoT and capital equipment, with sites in the UK, Netherlands and Romania operating to the same quality systems.

The team works alongside your engineers from the design stage, applying design-for-manufacturability (DFM) support to flex, rigid and rigid-flex PCB layouts before they reach the production line.

Our printed circuit board assembly capability includes high-speed Yamaha SMD pick-and-place lines, Juki lines for higher-flexibility builds, forced-air convection reflow soldering and lead-free wave soldering, backed by automatic optical inspection and in-circuit and functional test. For protection, we run an automated coating line, a Mycronic MY50, from our Romania facility, alongside back-potting and full encapsulation for the sections of a build that need it.

On the quality side, we operate to IPC-A-610 Class 3 for PCB assemblies and IPC/WHMA-A-620 Class 3 for cable and wire harness work, alongside multi-site ISO 9001, ISO 14001 and AS9100 certification, plus ATEX/IECEx compliance (EN ISO/IEC 80079-34:2018) for hazardous-area builds.

Whether you’re weighing up flexible circuitry against a rigid alternative for a new product or need PCB assembly services for an existing flex design, our engineering team can help you make that decision before tooling starts.

Not sure whether your next product needs flex, rigid or rigid-flex PCBs? Speak to our team and we’ll help you work through the trade-offs before you commit to a design.