FPC also called Flexible Printed Circuit board(Flexible PCB),has different characteristics than a rigid printed circuit board(Rigid PCB,like FR4 PCB), making it particularly useful for different applications.Different from Rigid PCB,FPC(Flexible PCB) are normally made of materials that can be bent,making the Electronic products are more resistant to vibrations and shocks, It definitely more suitable for high-reliability applications.By eliminating the need for bulky connectors and cables, flexible PCBs enable PCB design to create more compact and lightweight products. This can lead to cost savings in terms of materials and PCB manufacturing processes.
Flexible printed circuit boards(FPC) are quite different than rigid boards:
Material: Rigid boards are typically made out of FR4 (glass-epoxy );flexible circuits are made from polyimide.
Coverlay:Flex pcbs normally have a flexible solder mask or use coverlay ;rigid boards only use solder mask.
Stiffeners: Flexible printed circuit boards(FPCB) typically use FR4 or polyimide stiffeners to stiffen specified non-flexing regions where to protect components or connectors. Rigid boards do not require any stiffeners.
Example - Stiffener:
You can order your flexible circuit boards with a stiffener. The available thicknesses are: 0,075mm - 3,20mm
Standard thickness are 0,30mm and 0,20mm
Polyimide-Stiffener thickness available: 0,025mm - 0,225mm
FR4-Stiffener thickness available: 0,075mm - 3,20mm
Dielectric Constant: There is a wide range of dielectric constants for rigid board materials while flexible polyimide material is typically 3.4.
There are three type of flexible PCBs:
Flex PCB: The Flex PCB made out of Polyimide material so the overall circuit is 100% flexible.
Flex PCB with stiffener(s): a flex circuit needs to be rigid in a specified area where to protect the component or connector, FR4 or polyimide stiffeners can be added by lamination or PSA (pressure sensitive adhesive).
Rigid-flex PCB: A rigid-flex board is a combination of a rigid board and flex printed circuit board . The flexible layers are laminated between two rigid boards using no flow PP(prepreg).
There are many benefits to use a flexible printed circuit board in your application:
Lightweight: Flex circuit's polyimide material is much lighter than FR4.FPC’s Weight 75% to 90% less than Rigid PCB.
Thin: A typical 2-layer flex can range in thickness between 4 and 10 mils(0.1-0.25MM).FR4 PCB thickness range are in 0.2-0.3mm
Flexible: Obvioulys, with the ability to make bends, The Product designer have more freedom to decrease the overall mechanical footprint and make the product which need flex feature.
High Temperature: Polyimide flex materials are suited for very high temperatures compared to FR4.They are also resistant to oils, gases, and acids.
Flex PCBs are used in a wide range of applications across various industries:
Consumer electronics: Flex PCBs are commonly used in smartphones, tablets, laptops, and wearable devices, where space is limited and flexibility is required.
Medical devices: Flex PCBs are used in medical devices such as hearing aids, pacemakers, and implantable devices, where their flexibility and compact size are essential.
Automotive: In the automotive industry, Flex PCBs are used in applications such as dashboard displays, sensors, and control modules, where they must withstand harsh environments and constant vibration.
Aerospace: Flex PCBs are used in aerospace applications such as satellites, aircraft, and missiles, where their lightweight and compact size are critical.
Industrial: Flex PCBs are used in industrial applications such as robotics, automation, and process control, where their flexibility and durability are important.
