First, the flexible circuit board flexibility and reliability
Currently four kinds of flexible circuit board: single-sided, double-sided, multi-layer and just - screw combination type. "The cost of a single-sided flexible board is the lowest," says Friedman, "the single-sided flexible board should be used when the electrical performance is not high and the single-sided wiring can be used." This most common form has been used for commercial applications such as printers Inkjet cartridges and computer memory. Flex PCB The single-sided flexible plate has a layer of chemically etched conductive pattern, and the conductive pattern layer on the surface of the flexible insulating substrate is a rolled copper foil. Insulating substrates for flexible assembly may be polyimide (Kapton), polyethylene terephthalate (PET), Flex PCB aramid fiber paper (Nomex) and polyvinyl chloride (PVC).
The double-sided flexible plate is a conductive pattern formed by etching on both sides of the base film. The metal hole connects the two sides of the insulating material to form a conductive path to meet the flexibility of the design and use of the function. Flex PCB The cover film protects the single and double sided wires and indicates the position where the components are placed.
Multi-layer flexible board is three or more layers of single-sided flexible circuit board or double-sided flexible circuit board laminated together, through the drilling, Flex PCB plating to form a metal hole, formed in different layers of conductive path. This eliminates the need for complex welding processes. Although the number of conductive layers designed for this type of flexible type may be infinite, Flex PCB in the design of the layout, the assembly size, the number of layers and the interaction of the flexibility should be taken into account in order to ensure easy assembly.
The conventional rigid-flexible plates are composed of rigid and flexible substrates that are selectively laminated together. The structure is tight, forming a conductive connection with a metal hole. Flex PCB Taking into account the reliability and price factors, the manufacturer should try to keep as few layers as possible.
Flexible circuit board industry is in small scale but rapid development. Polymer Thick Film Act (PTF) is an efficient, low-cost process for producing circuit boards. Flex PCB The process is on an inexpensive flexible substrate, selectively screening conductive polymer inks. Its representative flexible substrate is PET. PTF conductors include screened metal fillers or toner fillers. The PTF itself is clean and uses lead-free SMT adhesives without etching.
There is also a mixed structure of the flexible circuit board, it is also a multi-layer board, but the multilayer conductive layer by the composition of different metals. Flex PCB This hybrid structure is mostly used in the relationship between electrical signal conversion and heat conversion and electrical performance of relatively harsh low temperature conditions. In this case, flexible hybrid circuits are the only viable solution.
Whether these flexible circuit boards are cost effective and whether they are optimally utilized can be evaluated by the convenience of the interconnection design and the total cost. Flex PCB The mainframe is not the same, the phone is in the form of a block layout; the portable computer is the XY orientation to locate the layout; the printer is in the form of a rigid-scratch PCB. These products are made of different materials of different prices to reduce each The cost of the root lead. Flex PCB Each design must undergo a typological assessment to achieve the best cost performance.
Second, the flexibility of flexible circuit boards
If the circuit design is relatively simple, the total volume is not large, and the space is appropriate, the traditional way to connect most of the more cost-effective. Flexible circuit boards are a better design choice if the lines are complex, handle many signals, or have special electrical or mechanical performance requirements. Flexible materials have a potential cost savings compared to rigid materials, eliminating the need for plug-ins.
High cost of raw materials is the main reason for the high price of flexible circuit boards. DiPalermo still believes that folding, bendable, and multi-plying will reduce the overall component size, Flex PCB reduce the use of materials, and reduce overall assembly costs, despite the fact that it is more expensive and creating trouble.
Third, the cost of flexible circuit boards is further reduced
Despite the above-mentioned cost factors, the price of flexible assembly is declining and becoming close to the traditional PCB. This is mainly the introduction of updated materials, improved production processes and changes in the structure of the reasons. With such an example, Flex PCB the use of an acrylic adhesive is eliminated on a rigid-flexible plate assembly with a large number of layers.
Now some of the updated materials because the copper layer is thinner and can make more fine lines. The thinner copper layer makes the assembly lighter and lighter, and the lighter and thinner assembly makes the flexible components more suitable for loading into smaller spaces. In the past, we used a roll process to adhere the copper foil to the adhesive-coated medium. Today, copper foils can be formed directly on the media without the use of adhesives. These techniques can get a few microns of copper, making the industry get 3 mil or even narrower narrow lines. "After removing the adhesive from the flexible circuit board, the flexible circuit board has flame retardant properties.
This will speed up the UL certification process and further reduce costs. Flex PCB It is even more important to obtain UL certification when flexible circuit boards continue to evolve from initial military industrial applications to civilian and consumer applications. The flexible board solder mask and other surface coatings further reduce the cost of flexible assembly. Over the past decade, Flex PCB some of these new materials and new processes have greatly reduced costs. At the same time, it is precisely because of such products have been widely recognized and demand, the cost of flexible materials is also declining.
In the next few years, the more sophisticated and more expensive assembly of flexible circuit boards will require a more innovative assembly, and the need to increase the hybrid flexible circuit board. The challenge for a flexible board industry is to enhance its technological advantages while maintaining synchronization with computers, telematics, consumer demand, and active markets. In addition, Flex PCB flexible circuit boards will play an important role in lead-free operations.