Flexible PCBs
Flexible PCBs
About Flexible PCB(PFC)
Flexible PCB (FPC), also known as the flexible circuit board, is a highly reliable, excellent flexible circuit board made of polyester or polyamide film as the base material. It owns the features of high wiring density, lightweight, thin thickness, and can be freely bent and folded, and is very popular.
Advantages and disadvantages of Flexible PCBs
Flexible electronic assemblies can be built using the same parts used for rigid PCBs, allowing the board to form to the desired shape or bend following design demand. Flexible PCBs offer several potential benefits, including:
Lightweight
Flexible PCBs are lightweight and can reduce weight by up to 75% compared to other PCB materials.
Good heat dissipation
Flexible PCBs provide better airflow and heat dissipation due to the streamlined design of polymer substrates and printed circuit boards.
High-reliability
Flexible PCBs increase reliability by less soldering. Flexible PCBs perform particularly well in vibration and shock environments, and flexible PCBs can be bent up to 500 million times.
Bendable
Flexible PCBs are bendable and can form complicated three-dimensional shapes with branches that branch out to multiple connectors that wire cables cannot achieve.
Good dielectric constant
Flex PCBs offer better electrical performance on low dielectric constant, which allows fast electrical signal transmission and reduces noise figures. Higher heat transfer performance makes assembly work easy and fast.
Easy to assemble
Flexible PCBs reduce assembly costs by replacing multiple circuits with a single flexible assembly, saving both assembly time and material.
Disadvantages
Materials are expensive Substrate polymer materials for flexible circuits are expensive compared to rigid boards.
High manufacturing costs Rigid boards can be manufactured manually, while flexible PCBs require automated equipment. Modifying or repairing the design is not feasible for flexible PCBs because removing the cover from the conductive material is not easy. Last but not least is the flex PCB’s sensitivity; engineers must have good experience handling FPC during component mounting.
Current limitation A major limitation of electronic devices using flex circuits is that they cannot pass higher currents. The maximum copper width available on polymer substrates is 2 ounces because beyond this level, the flex PCBs will not be flexible since copper is a hard material. Applications with higher current requirements use rigid PCBs.
Applications of Flexible Boards
ICT Industry
Flexible PCBs are very robust in terms of signal and atmospheric conditions. Hard drives in computers contain Flex PCBs. Since these PCBs provide high data transfer rates on a physically small circuit board. Electronic devices such as printers, hard drives, calculators, and laptop LCDs are often designed with flexible PCBs.
Smartphone
The waterproof and bendable features of Flex PCBs enable mobile phones to achieve more functions in a limited volume.
Medical Electronics
Wearables are used to track physical fitness; these products are very compact and sophisticated. Flexible PCBs can implant sensors on the patient’s skin. Flexible PCBs bring about this revolution in wearable medical devices.
Automotive Electronics
Flexible PCBs can achieve compactness in their designs, regardless of shape, these PCBs can be placed in a limited space and still work efficiently. Flexible PCBs are used in engine management computers, airbag controllers, and other electronic components for automotive products. Since cars are often exposed to high temperatures, this is tolerable for flexible PCBs.
Industrial Control
Flexible PCBs can withstand extreme weather conditions and perform well even in harsh environments. RF equipment is often designed with Flex PCBs because the robust nature of these PCBs leaves signal strength unaffected. In addition, Flex PCBs are used in industrial machines and power distribution control systems.
Sensors
Flex PCBs have revolutionized sensors, and modern sensors are fabricated on flex PCBs. These sensors can be placed in limited, irregular spaces for designs or more compact products. Such as sensors used in the oil and gas industry to measure humidity, humidity, and pressure. Flexible circuits use polyimide or similar polymers as substrates. These materials dissipate heat faster than rigid PCB materials and can withstand extreme temperatures.
Aerospace Industry
Aircraft electronic systems are often crammed with cables. A typical Airbus contains nearly 100 kilometers of cable, while a helicopter contains about 12 kilometers. There can be no compromises regarding the reliability and performance of aircraft systems. The flexible PCB reduces weight and lifts significantly even when subjected to mechanical shock, making it ideal for aircraft.
Our Flexible PCB
Layers: 2 L Thickness: 1.2mm
Out Layer Copper Thickness: 1 OZ
Inner Layer Copper Thickness: 1 OZ
Min Hole Size: 0.2mm Min Line Width: 3mil
Surface Finish: ENIG
Application: Computer
Layers: 2 L Thickness: 0.8mm
Out Layer Copper Thickness: 1 OZ
Inner Layer Copper Thickness: 1 OZ
Min Hole Size: 0.3mm Min Line Width: 3mil
Surface Finish: ENIG
Application: Consumer Electronics
Layers: 1 L Thickness: 0.6mm
Out Layer Copper Thickness: 1 OZ
Inner Layer Copper Thickness: 1 OZ
Min Hole Size: 0.3mm Min Line Width: 2mil
Surface Finish: ENIG
Application: Medical
What are the difficulties of Flexible PCBs manufacturing?
High-density FPC circuit miniaturization and via diameter miniaturization.
The manufacturing process is complicated. In contrast, the production yield is relatively low for Flexible PCBs.
High dimensional stability. With the development of high-density FPC circuits, the requirements for material size are more stringent.
The life expectancy of high deflection products is increased from 100,000 to 150,000 times, and the requirements for the FPC manufacturing process are also getting higher and higher.
- The FPC substrate is thin, soft, and easy to deform. It isn’t easy to assemble SMD on the FPC.
Eashub’s capability on Flexible PCBs
| Feature | Capability |
| Quality Grade | Standard IPC 2, IPC 3 |
| Number of Layers | 1 – 10 layers |
| Material | DuPont or Local Polyimide |
| Max Board Size | Max 400mm x 610mm |
| Final Board Thickness | 0.08mm – 0.8mm |
| Copper Thickness | 0.5oz – 2.0oz |
| Min Tracing/Spacing | 2mil/2mil |
| Min Drilling Hole Diameter | 8mil |
| Solder Mask Color | Green, Matte Green, Yellow, White, Blue, Purple, Black, Matte Black, Red |
| Silkscreen Color | White, Black |
| Surface Treatment | Immersion gold, OSP, Immersion Silver, Immersion Tin |
| Tolerance of dimension | ±0.05mm |
| Lead Time | 2 – 28days |
What are the main differences between Flexible PCBs and Rigid PCBs?
Physical properties
FPC is a flexible circuit board and can be bent while Rigid PCBs can’t.
Base material
The base material of FPC is polyimide or polyester film, and the base material of PCB is epoxy resin and glass fiber cloth.
Application environment
For many products with very strict structural design, FPC is the only choice.
Price
FPC price is higher than Rigid PCBs
