FPC flexible circuit board composition process

- May 13, 2020-

FPC flexible circuit board composition process

Flexible circuit board is a kind of PCB with high reliability and excellent flexibility, which is made of polyimide or polyester film. Referred to as soft board or FPC, it has the characteristics of high wiring density, light weight and thin thickness.

Prenatal treatment

There must be a complete and reasonable production process to make a good quality FPC board. From pre-treatment to final delivery, every procedure must be strictly implemented. In the production process, in order to prevent too many short-circuit and low yield or reduce drilling, calendering, cutting and other technological problems, FPC board waste reporting and replenishing problems, and evaluate how to select materials to achieve the best effect of the flexible circuit board used by customers. Prenatal pretreatment is particularly important.

There are three aspects that need to be dealt with in prenatal pretreatment, all of which are completed by engineers. The first is the FPC board engineering evaluation, which is mainly to evaluate whether the FPC board of the customer can be produced, whether the production capacity of the company can meet the requirements of the customer's board manufacturing and the unit cost; if the engineering evaluation is passed, the next step is to prepare materials immediately to meet the raw material supply of each production link. Finally, the engineer carries out engineering documents such as the customer's CAD structure chart, Gerber line data, etc Processing, to adapt to the production environment and production specifications of the production equipment, and then the production drawings and mi (engineering process card) and other data are transferred to the production department, document control, procurement and other departments to enter the regular production process.

production process

Double sided board system

Opening → drilling → PTH → electroplating → pretreatment → dry film sticking → alignment → exposure → development → graphic electroplating → film stripping → pretreatment → dry film sticking → alignment exposure → development → etching → film stripping → surface treatment → coating film sticking → pressing → solidification → nickel deposition → character printing → shearing → electrical measurement → punching → final inspection → packaging → shipment

Single panel system

Open material → drill hole → stick dry film → align → expose → develop → etch → remove film → surface treatment → stick cover film → press → solidify → surface treatment → sink nickel gold → print character → cut → electric measurement → punching → final inspection → package → delivery

Production process

Surface treatment: gold deposition, anti-oxidation, gold plating, tin spraying

Shape processing: manual shape, CNC (numerical control machine tool) cutting, laser cutting

Base copper thickness: 1 / 3 oz, 1 / 2 oz, 1 oz, 2 oz, 4 oz


According to the characteristics of flexible circuit board materials and widely used fields, in order to save volume and achieve certain accuracy more effectively, the characteristics of three-dimensional space and thin thickness are better applied to digital products, mobile phones and laptops. The instrument used for FPC testing is optical image measuring instrument.


1. Short: short assembly time

All lines are configured. Eliminate the connection of redundant cables

2. Small: smaller than PCB

It can effectively reduce product volume. Increased portability

3. Light: lighter than PCB (hard board)

Can reduce the weight of the final product


4 thin: thinner than PCB

It can improve the softness. Strengthen the assembly of three-dimensional space in finite space

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