Flexible Printed Circuits Introduction
Enabling Technology
Flexible Circuits consist of conductive strips of metal enscapulated with insulating dielectric material. They resist moisture and contamination and they are insulated from external shorts, providing holes or contact surfaces for interconnection.
Understanding a package’s electrical requirements, and not over designing, permits taking full advantage of flexible circuit’s potential compared to conventional wiring. Among the benefits are weight and bulk reduction, higher density, shorter assembly time and fewer errors, reproducible electrical characteristics, custom shielding, improved reliability, ability to interconnect moving parts, and an engineered appearance.
The mechanical and electrical characteristics of flexible circuits determine what type should be used.
Total installed cost, including inspection, interconnection, fixturing and testing, must be weighed against the advantages of each:
- Single-sided flexible circuits have one layer of metal on a dielectric.
- Double-sided flexible circuits have metal on both sides.
- Sculptured circuits are single or double-sided circuits created from thick copper that allows connections such as fingers and pads to be thick while reducing the copper thickness in the circuitry.
- Multi-layer flexible circuits have several layers that are registered to each other and are separated by a cured layer of adhesive during lamination, with interlayer connections via plated-thru holes.
- Multi-layer rigid-flex is the combination of flex within and extending from the rigid section of the PC-Board.
Flex circuits are usually designed as:
- Flex to install where the flex is bent once or a few times during package assembly.
- Flex which is designed for continuous flexing.
Prime Function of Flex:
- Very thin and light weight with the ability to conform to small spaces and contoured shapes
- Eliminate or enable use of smaller, less expensive connectors
- Provide mechanical flexing
- Shield radiated noise for EMI
Flexible Printed Circuitry
The Connection & Enabling Technology
Today's sophisticated packaging requirements require complex electrical and mechanical interfaces. Flexible Printed Circuits provide a preferred electrical connection while simplifying the ever increasing mechanical challenges.
Miniaturization is continuing to demand increased performance of each component. Few products other than Flexible Printed Circuits can provide mechanical and electrical interfaces in a cost effective solution within small packages.
The application and configurations using Flexible Printed Circuits are unlimited to ones innovations. This provides a huge matrix of design choices and material choices. The performance of the Flexible Printed Circuit is directly tied to the understanding of the application and the design and material choices.
PFC believes we can be your partner and guide working through the details to find the best solution to you interconnect challenge using Flexible Printed Circuitry.
Benefits of Flexible Circuits
- Cost Savings - Typically 30% to hand wiring
- Weight Savings - Typically 70%
- Space Savings - Typically 60%
- Reliability Improvements
- Mechanical and Electrical Repeatability
- Wiring Errors Eliminated
- Conformability
- Point to Point connectors on active hole
- Minimizes the quantity of connections
When to Use Flex
- Density. Are more than 20 conductors needed?
- Is space limitation important?
- Is weight an important consideration?
- Does assembly labour need to be reduced?
- Is reliability critical?
- Is repeatability of electrical characteristics crucial?
- Is integral shielding or impedance control required?
- Is dynamic flexing of circuits needed?
- Eliminate or enable use of smaller, less expensive connections.