(FPC’s are custom-made products. The picture and parameters shown are for reference only.)

This four-layer flexible circuit is constructed with a polyimide (PI) substrate, designed for wireless router applications. Each layer utilizes 1oz copper thickness, sourced from Shengyi base laminate, ensuring reliable conductivity and mechanical flexibility. The circuitry is protected by a yellow covering layer, with immersion gold plating applied to the pads for enhanced solderability and corrosion resistance. Both ends of the circuit feature integrated connectors, enabling seamless system integration. Fabricated to IPC 6012 Class 2 standards using provided Gerber data, this flexible circuit balances precision engineering with durability, suitable for high-frequency signal transmission in compact wireless networking environments.

Features and Benefits

1. Excellent flexibility

2. Reducing the volume

3. Weight reduction

4. Consistency of assembly

5. Increased reliability

6. Low cost

7. Continuity of processing

8. Material optionality

9. Diversified shipping method

10. Engineering design prevents problems from occurring in pre production.

Multilayer flexible circuit production primarily builds upon single-sided and double-sided PTH flexible PCB technologies, evolving from conventional bonded covercoated double-sided designs. While multilayer construction offers enhanced functionality, excessive layer stacking in flexible circuits is generally discouraged due to reliability concerns.

Materials and Thicknesses of Multilayer FPC

Dielectric Substrates:

50μm (2mil) polyimide preferred for enhanced stability and handling over 25μm (1mil) alternatives

Copper Foil:

35μm (1oz) standard thickness, selected based on current-carrying requirements

Covercoat Systems:

• 25μm (1mil) polyimide recommended for 35μm (1.4mil) copper foil encapsulation

• 25μm (1mil) acrylic adhesive optimal for reliable lamination (excessive adhesive risks barrel/foil cracks)

Outer Layers:

The bonding surfaces of outer layers must remain free of conductive traces to prevent air entrapment during lamination, which could compromise layer adhesion and long-term reliability.

Bonding Methodology:

Sheet adhesives serve as the primary bonding medium when integrating covercoated flexible inner layers with rigid board sections, ensuring proper interlayer connection while maintaining flexibility where required.

A simplified flow diagram is shown below.

More Displays of Black Flexible Circuits