PCB Tech - How to manage the quality of flexible circuit boards

FPC quality control, that is, the quality management and control process of Flexible Printed Circuit Boards (FPC), this control process directly affects the quality of FPC, and ultimately affects the quality of finished electronic products. If a manufacturer wants to produce an FPC with excellent quality, it must analyze and control it from the five aspects of "materials, machines, methods, people, and environment".

FPC circuit board

material

"Materials" means materials. This is the most important thing. It is like a majestic high-rise building that requires a solid foundation. In the production of FPC, polyimide copper clad laminate substrate, polyimide protective film, screen printing ink, double-sided adhesive tape, and reinforcing sheet are mainly involved. Choosing good raw materials is the prerequisite for producing high-quality FPC. The advantages of a good substrate are mainly stable performance, strong environmental endurance, and good compatibility. For example, copper-clad polyimide substrate, material from DuPont, USA, copper ions in copper foil are uniformly distributed, high density, polyimide insulation PI, stable, high breakdown coefficient, compact pressure between the two, and peel strength Very high, all have passed the US UL certification, EU ROSH certification, etc., and can provide a complete SGS report;

while some other small manufacturers produce and process materials on their own, especially in China, in order to maximize profits or exclusively supply low-end markets. The quality of the base material is self-evident, and even the two can be distinguished between good and bad just by comparing the two. The quality of the substrate determines the stability, folding resistance, breakdown voltage, and environmental endurance of the FPC; in addition, the difference in the texture of the polyimide protective film mainly affects the maximum and minimum environmental endurance temperature of the product. The breakdown voltage coefficient and the peel strength, its quality also directly affects the FPC's environmental adaptability. Ink, adhesive tape, and reinforcing sheet, these are auxiliary materials and will not affect the electrical performance of the product, but the use of good auxiliary materials, such as 3M tape, sun ink, etc., can improve the overall texture of the FPC and improve the assembly to a certain extent Accuracy, a high-quality FPC, of course, it is indispensable for their assistance.

machine

The second is "machines", that is, production machines and equipment. The precision of machinery and equipment directly determines the quality of FPC finished products, and high-precision equipment has smaller dimensional tolerances. In the FPC production process, high precision requirements are required, such as automatic drilling machines (determining the size of the smallest aperture), exposure machines (determining the minimum line width and line spacing that can be produced), molds (determining the size of the shape tolerance), laser Cutting machine (provides smaller precision than die punching, but has a long processing cycle and is only suitable for samples or very small batches). This is an analysis from the "things" aspect.

Law

First-rate projects, if entrusted to third-rate people, often make them third-rate; and third-rate projects, if they are entrusted to first-rate people, can often be made first-rate. Therefore, personnel also account for an important part of the entire production process. In the FPC manufacturing process, after the production process and methods are improved, employees are required to operate in accordance with this process standardization. At the same time, the management department also needs to manage the personnel from many aspects to stimulate the enthusiasm of the employees and reduce the fatigue of the employees.

ring

The last is the production environment. In the FPC production process, there are several processes that must be carried out in a dust-free environment, such as alignment, exposure, and protective film bonding. Dust particles will directly affect the integrity and continuity of the FPC finished circuit, and the dust particles will pass through. Too much, will make the FPC too much impurities, not only affect the appearance, and even cause a short circuit. Large manufacturers, in order to ensure the cleanliness of FPC, even survive and process completely in a dust-free environment. Dust-free is only one aspect of the environment, and proper management and control of employees is also a link to ensure the production environment.

Summarize

Raw materials, production equipment, production methods, personnel, and production environment are all five. Good quality FPC products can be made only when management is in place. The five complement each other and are indispensable. These are the five cores of FPC quality control. Of course, this also requires financial support, and there will be a certain contradiction with interests in a short period of time, but it is the right direction for the development of FPC manufacturing enterprises.