Manufacturing Process of Flexible Printed Circuit

Flexible Printed Circuits (FPCs) are integral to modern electronics, and their production demands precision, scalability, and strict quality control. Factories specializing in FPC manufacturing must balance advanced technology with efficient workflows to meet high-volume demands while ensuring reliability.

The flexible printed circuit manufacturing process is a highly precise and multi-step procedure that transforms raw materials into flexible, lightweight, and high-performance circuit boards.

Single-sided and double-sided flex PCBs are the two main types of flexible PCB, and each type has a different manufacturing process. Flex Plus, the flexible PCB manufacturer, will help you understand their differences.

Manufacturing Process of Single-sided Flexible Printed Circuit Board

Most single-sided flexible circuits are typically manufactured by bonding copper foil to a layer of polyimide dielectric film. This bonding process typically uses a layer of adhesive to ensure a strong bond between the copper foil and the polyimide. Another manufacturing method is to bond the copper directly to the dielectric without the use of an adhesive, and this composite material is called an adhesiveless substrate.

The formation of a copper circuit is achieved through photolithography imaging, development, and etching. One method is to pre-punch holes in the polyimide material. The pre-punched polyimide material is laminated to the substrate on which the copper circuit has been formed to form a covering layer to protect the circuit. Another method is to use optical imaging technology to accurately cover the solder mask layer in specific areas of the circuit to protect the circuit and prevent short circuits during soldering (the solder mask layer, as a selective dielectric, only covers the parts that need protection and does not affect other parts of the circuit).

Single-sided Flex PCB

A single-sided flex PCB is the simplest form of flexible circuit board, characterized by a circuit pattern on only one side of the substrate. The flexible printed circuit manufacturing process includes the following steps:

Material cutting → CNC drilling → Dry film laminate → alignment → exposure → developing → etching → decoating → surface treatment → pasting covering film → pressing → curing → surface treatment → immersion nickel gold → printing characters → shearing → electrical measurement → punching → final inspection → packaging → shipping

Manufacturing Process of Double-sided Flexible Printed Circuit

A double-sided flexible PCB is a type of FPCB that has conductive copper layers on both sides of a flexible dielectric substrate. Double-sided circuit bos begin with two copper layers separated by an insulating film. Similar to single-sided designs, the bonding between the substrate film and the copper conductors can use adhesive or be adhesiveless. 

Double-sided Flex PCB

 Double-sided Flex PCB has circuits on both sides of the substrate, allowing for more complex designs and greater functionality. The manufacturing process for the double-sided circuit is more intricate than the single-sided circuit, involving the following steps:

Material cutting → CNC drilling → PTH → copper plating → pretreatment  → Dry film laminate → aligning → exposure → developing → graphic plating → decoating → pretreatment → Dry film laminate → alignment exposure → developing → etching → decoating → surface treatment → pasting covering film → pressing → curing → immersion nickel gold→ printing characters → shearing → electrometering → punching → final inspection → packaging → shipping

The flex PCB material usage and cost of single and double-sided PCBs are different. A double-sided circuit requires more materials and involves more complex manufacturing steps, resulting in higher costs. Flexible PCB manufacturer Flex Plus provides more cost-effective solutions by optimizing its manufacturing processes.

Summary

Flex Plus is a flexible PCB manufacturer that focuses on various FPCBs and provides customized solutions to meet the needs of different customers. The Flex PCB products produced by Flex Plus are widely used in medical and health, new energy vehicles, communication products, precision modules for mobile phones, industrial control, Bluetooth hearing aids, and other technological fields. Flex Plus has established good cooperative relationships with many well-known customers in North America, Europe, Japan, Southeast Asia, and mainland China.