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The advantages and effects of flexible circuit boards
2021-09-23
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Author:KAVIE
  1. Flexibility and reliability of flexible circuit boards

    flexible circuit boards

        Four types of flexible circuit boards are currently popular: single-sided, double-sided, multilayer, and rigid-flex combination. "Single-sided flexible board has the lowest cost. When the electrical performance is not high, and single-sided wiring can be used, single-sided flexible board should be used." This most common form has been commercialized, such as inkjet cartridges and printers. Computer memory. The single-sided flexible board has a layer of chemically etched conductive patterns, and the conductive pattern layer on the surface of the flexible insulating substrate is a rolled copper foil. The insulating substrate used for flexible assembly can be polyimide (Kapton), polyethylene terephthalate (PET), aramid fiber paper (Nomex) and polyvinyl chloride (PVC).

        The double-sided flexible board is a conductive pattern made by etching on both sides of the base film. The metallized hole connects the patterns on both sides of the insulating material to form a conductive path to meet the design and use function of flexibility. The cover film can protect single and double-sided wires and indicate where the components are placed.

       Multi-layer flexible board is to laminate three or more layers of single-sided flexible circuit board or double-sided flexible circuit board together, through drilling and electroplating to form metallized holes, forming conductive paths between different layers. In this way, there is no need to use a complicated welding process. Although the number of conductive layers designed for this flexible type can be unlimited, in order to ensure ease of assembly when designing the layout, the mutual influence of assembly size, number of layers and flexibility should be considered.

Second, the economy of flexible circuit boards

        If the circuit boards design is relatively simple, the total volume is not large, and the space is suitable, most of the traditional internal connection methods are more cost-effective. If the circuit is complex, processes many signals, or has special electrical or mechanical performance requirements, flexible circuit boards are a better design choice. Compared with rigid materials, flexible board materials have a potential cost saving reason, which is the elimination of connectors. The cost of raw materials is the main reason for the high price of flexible circuit boards. Although the raw materials are relatively expensive and the manufacturing is troublesome, the foldable, bendable, and multi-layer splicing functions will reduce the size of the overall assembly, reduce the materials used, and reduce the total assembly cost.

Third, the cost of flexible circuit boards is being further reduced

        Despite the aforementioned cost factors, the price of flexible assembly is declining, becoming close to traditional PCBs. This is mainly due to the introduction of newer materials, improved production processes and changes in structure. There is an example of eliminating the use of acrylic adhesives on rigid-flex board assemblies with many layers. Now some newer materials can produce finer lines because of the thinner copper layer. Thinner copper layers make components lighter and lighter, and lighter and thinner assemblies make flexible components more suitable for smaller spaces. Today, it is possible to produce copper foil directly on the media without the use of adhesives. The copper layer of several microns that can be obtained by these technologies enables the industry to obtain fine lines with a width of 3 mil or even narrower. "After removing the adhesive from the flexible circuit board, the flexible circuit board has flame retardant properties. This can speed up the UL certification process and further reduce the cost. When the flexible circuit board continues to rapidly develop from the initial military industrial application to For civil and consumer applications, obtaining UL certification is even more important. Flexible board solder masks and other surface coatings have further reduced the cost of flexible assembly. In the past ten years, some of these new materials and new processes have greatly reduced costs At the same time, it is precisely because such products have been widely recognized and demanded that the cost of flexible materials is also falling.