/For Global Electronics Manufacturers/
Flex PCB Assembly
PCBSAIL provides flex PCB assembly services for engineering prototypes, pilot builds, low-volume orders, and repeat production.
Flexible circuits need different handling from rigid FR-4 boards. Low stiffness and localized stiffeners can affect printing, placement, reflow, inspection, and final installation. We review these variables before defining the manufacturing route for each project.
SMT, THT, Mixed
AOI, X-ray, Functional Testing
What Is Flex PCB Assembly?
Flex PCB assembly, also called flexible printed circuit assembly or FPC assembly, is the process of mounting, soldering, inspecting, and testing electronic components on a flexible circuit.
Surface-mount technology, through-hole components, connectors, or a mixed process was used in Flex PCB assembly depending on the product design.
The assembly sequence is similar with rigid-PCB production, but the process controls are not identical. A flexible circuit may move or distort during paste printing, placement, heating, cooling, handling, and installation.
A repeatable carrier, suitable panel design, controlled material handling, product-based reflow profiling, and flex-aware inspection help keep the circuit registered and protect bend-sensitive features.
Flex PCB Assembly Services
We support customers who need one coordinated manufacturing partner as well as customers who retain control of selected materials or components.
Our Turnkey Flex PCB Assembly service included flexible PCB fabrication, approved component sourcing, SMT or mixed assembly, inspection, customer-defined testing, labeling, packaging, and delivery.
Customers may consign proprietary, allocated, controlled, or long-lead-time parts while we coordinates the remaining approved components, PCB fabrication, assembly, and quoted inspection or testing.
For consigned projects, customers supply the complete approved component kit. We are responsible for receiving and kitting checks, assembly, and the inspection or test scope defined in the quotation.
Prototype and new-product-introduction builds help expose footprint or polarity questions, flex-panel handling risks, sourcing gaps, inspection limitations, and test-access issues before the design moves into repeat production.
We record project questions and agreed changes against the released product revision.
Repeat flex PCBA production depends on controlled revisions, approved materials, stable tooling, documented work instructions, and defined inspection coverage. We use the prototype and pilot stages to establish the production package before scale-up.
Flex PCB Assembly Capabilities
Our flex PCB assembly service support SMT placement on single-sided, double-sided, and rigid-flex circuit boards.
Capability | Specification |
Assembly Technologies | SMT, THT, Mixed-technology Assembly |
Min. SMT Component | 01005 |
Min. IC Pitch | 0.30 mm |
Min. BGA Pitch | 0.30 mm |
Largest Component Body | Up to 45 × 98 mm |
Max. Component Height | Up to 25 mm |
PCB Size Range | 50 × 50 mm to 510 × 460 mm |
Inspection Options | SPI, Visual Inspection, AOI, and X-ray |
Testing Options | Electrical testing, functional testing and so on. |
Value-Added Services | Laser Marking, Conformal Coating, Potting, Press-Fit Assembly, Mechanical Assembly |
What Should You Send?
- 1. Gerber or ODB++ fabrication files
- 2. Bill of materials with manufacturer details
- 3. Centroid or component placement data
- 4. Assembly drawings and special instructions
- 5. Testing, programming, and packaging requirements
"Ready To Start Building Your PCB?"
Flex PCB Assembly Cost
Flex PCB assembly’s cost is depended by several key factors. On average, flexible PCB fabrication ranges between $0.50 and $5.00 per square inch, but final assembly costs depend on additional parameters.
There are some factors depending Flex PCB Assembly cost.
Board Size
Larger circuits require more materials and processing time.
Number of Layers
More layers increase manufacturing complexity and cost.
Material
Flexible substrates such as polyimide and specialized adhesives increase costs compared with standard FR-4 materials.
Component Count
Higher component density increases assembly complexity and inspection requirements.
Special Design Requirements
Features Such As:
- Controlled Impedance
- Microvias
- Custom Stiffeners
- Fine Pitch Components
Our Flex PCB Assembly Process
Our each flex PCBA build follows a controlled route from file review to final release.
1. Build-Package Review
We review the Gerber or stack-up, BOM, assembly drawings, and so on.
2. Flexible PCB Fab and Component Preparation
We will produce flex PCB. We source approved parts against the BOM and agreed alternative-approval process.
3. Incoming Inspection
We check the received flexible circuits and components against the defined project records.
4. Carrier Loading and Stencil Preparation
When the flex panel cannot remain flat and registered by itself, it is loaded into the approved carrier or support method. Locating features, fiducials, restraint, access, cleanliness, and repeatability are checked before printing.
5. Solder Paste Printing and Component Placement
Solder paste is deposited using the released stencil or dispensing method.
6. Reflow
The populated assembly passes through the approved reflow process.
7. Inspection and Testing
Visible workmanship may be reviewed by visual inspection or AOI. BGA, QFN, LGA, or other hidden-joint packages will be checked by X-ray.
Flex PCB Assembly Inspection and Testing
Our inspection and testing plan is based on product risk, process requirements, and contractual specifications.
1. Incoming Material Inspection
Incoming materials and components are checked against the approved BOM and purchasing requirements.
2. Solder Paste Inspection
After solder paste printing, 3D SPI can be used to evaluate paste volume, height, area, shape, and positional alignment.
3. AOI
After component placement and reflow, AOI and visual inspection can evaluate component presence, polarity, rotation, alignment, solder bridging, and visible workmanship conditions.
4. X-Ray Inspection for Hidden Joints
X-ray inspection can be applied when concealed solder joints require additional verification.
5. Electrical Testing
Customer-defined electrical testing can be included to verify selected opens, shorts, circuit nodes, component values, interfaces, or other electrical characteristics.
6. Final Release Inspection
Before shipment, final release inspection verifies workmanship, product identification, labeling, quantity, packaging, and required production documentation.
Factory Glance
Our factory was equipped with automated SMT lines, intelligent process control systems, and advanced inspection equipment to support reliable Flex PCB assembly from prototypes to high-volume production.
Industries We Have Previously Served
Flex PCB Assembly is widely used across modern electronics due to its ability to bend, fold, and conform to complex geometries while maintaining reliable electrical performance.
Automotive Electronics
The automotive industry increasingly relies on flex PCB assembly for advanced electronic systems, especially in electric vehicles (EVs) and autonomous driving technologies.
- Advanced Driver Assistance Systems (ADAS)
- In-Vehicle Infotainment Systems
- Instrument Clusters And Dashboards
- Battery Management Systems (BMS)
- Lighting Systems (LED Modules)
Industrial Automation
Industrial systems require durable and reliable electronics capable of operating in demanding environments. Flexible PCB assemblies provide excellent performance in these conditions.
- Robotics And Motion Control Systems
- Industrial Sensors
- PLC (Programmable Logic Controllers)
- Machine Vision Systems
- Control Panels And Automation Equipment
Medical Devices
Flex PCB assembly is critical in the medical field, where devices must be small, lightweight, and highly reliable.
- Wearable Health Monitoring Devices
- Diagnostic Imaging Equipment
- Implantable Medical Devices
- Portable Medical Instruments
- Patient Monitoring Systems
Consumer Electronics
Flexible PCB assemblies are extensively used in consumer electronic devices, where compact size, lightweight design, and high reliability are critical.
- Smartphones
- Tablets and Laptops
- Wearable Devices (smartwatches, fitness trackers)
- Foldable and Flexible display systems
- Gaming Devices
Telecommunications
With the rapid development of communication technologies, flexible PCB assemblies are widely used in high-frequency and high-speed electronic systems.
- 5G Communication Equipment
- RF Modules And Antennas
- Networking Hardware
- Signal Transmission Modules
Energy Systems
Flexible PCB assemblies are increasingly used in renewable energy applications, especially where space and environmental conditions are challenging.
- Solar Power Systems
- Energy Storage Systems
- Portable Energy Devices
- Smart Grid Components
Aerospace
In aerospace and defense systems, reliability and performance under extreme conditions are essential. Flex PCB assemblies are widely used due to their resistance to harsh environments and mechanical stress.
- Avionics Systems
- Satellite Communication Equipment
- Radar And Navigation Systems
- Military Communication Devices
- UAV (Drone) Electronics
Fast Quotation
Our professional sales and engineering teams provide fast PCB quotes and technical support. Simply send us your Gerber files, BOM, and assembly drawings, and we will respond promptly with a competitive solution.
- Gushu Tangxi Second Industrial Zone, Shenzhen
- +86 755 2335 0814
- +86 135 1078 8094
- sales@pcbasail.com
FAQ About Flex PCB Assembly
1. What is Flex PCB Assembly?
Flex PCB Assembly refers to the process of mounting electronic components onto flexible printed circuit boards (FPCBs) made from materials such as polyimide. These circuits can bend, twist, and fold, making them ideal for compact and space-constrained electronic applications.
2. What Is The Difference Between Flex PCB And Rigid PCB Assembly?
The main difference lies in the substrate material and mechanical properties:
- Flex PCB Assembly uses flexible materials that allow bending and folding
- Rigid PCB Assembly uses solid fiberglass (FR4) that cannot flex
Flex PCBs are better suited for compact, lightweight, and dynamic applications, while rigid PCBs are typically used for standard electronic designs.
3. Why Is Flex PCB Assembly More Expensive Than Rigid PCB Assembly?
Flex PCB assembly generally costs more due to:
- Specialized Flexible Materials (E.G., Polyimide)
- Custom Carrier Fixtures (Tooling Pallets)
- More Complex Manufacturing Processes
- Lower Production Throughput
- Tighter Process Control Requirements
These factors increase both production complexity and cost.
4. What Files Are Required For A Flex PCB Assembly Quote?
To receive an accurate quotation, you typically need to provide:
- Gerber Files (PCB Layout)
- Bill Of Materials (BOM)
- Pick And Place (Centroid) Files
- Assembly Drawings
- Special Requirements (If Any)
Providing complete documentation helps speed up the quoting and manufacturing process.
5. What Is The Typical Lead Time For Flex PCB Assembly?
Lead time depends on design complexity and production volume:
- Prototype: 24 hours to 5 days
- Small batch: 5–10 days
- Mass production: 2–4 weeks
PCBSAIL offers fast-turn flex PCB assembly, with prototypes completed in as little as 8 hours when components are ready.
6. What Materials Are Used In Flex PCB Assembly?
Common materials include:
- Polyimide (PI) – most widely used flexible substrate
- Polyester (PET) – for low-cost applications
- Copper foil – conductive layer
- Adhesives and coverlay films
- FR4 or polyimide stiffeners
Material selection depends on application requirements such as temperature resistance and flexibility.
7. What Are Stiffeners In Flex PCB Assembly?
Stiffeners are rigid materials attached to specific areas of a flexible PCB to provide mechanical support.
They are typically used for:
- Connectors
- Component Mounting Areas
- Soldering Reinforcement
Common stiffener materials include FR4 and polyimide.
8. What Are The Common Defects In Flex PCB Assembly?
Some common issues include:
- Solder Bridging
- Insufficient Solder Joints
- Component Misalignment
- Delamination Due To Moisture
- Warping Caused By Thermal Stress
These can be minimized through proper DFM design, controlled processes, and strict quality inspection.
9. What Is The Minimum Component Size Supported In Flex PCB Assembly?
Advanced SMT lines can handle components as small as:
- 01005 (0.4mm × 0.2mm)
- Fine-pitch QFN and BGA Packages
PCBSAIL supports high-density assembly with precise placement accuracy.
10. Do You Offer Turnkey Flex PCB Assembly Services?
Yes. PCBSAIL provides complete turnkey solutions, including:
- PCB Manufacturing
- Component Sourcing
- Assembly
- Testing
- Final Delivery
This simplifies the supply chain and reduces lead time.
11. Can BGAs be Assembled on flex PCB?
Yes, with correct support tooling, process control, and inspection.