Flexible Circuit: Why it is the choice of millions

One of the processes used to manufacture electronics is called the flexible circuit. In fact, electronic manufacturing uses two basic types of electronic assemblies—the flexible circuit boards and the printed circuit boards. Whereas a flexible circuit design comprises a layer of plastics such as polymide film that can be operated with an electronic flexible circuit, printed circuit boards comprise many layers of copper sheets that are laminated together to form a robust platform for component wiring.

The basic difference between these two types is that printed circuit boards are not flexible enough to be bent but flexible printed circuit boards, as the name suggests, can be bent while being used without causing any harm to the components.

Flexible circuits are used in cameras and computer keyboards, mobile phones, notebooks, personal digital assistant and information appliances, among other things. They are used because they can be assembled easily, are inexpensive and take up low volumes. They are used in packages with little space and they are stacked into rigid boards, thereby forming a 3-D connection. In fact, it can be used as an interface between an LCD, a HDD, a floppy disk driver and a CD and a motherboard.

These circuits with electrical and optical components are very essential for the optoelectronics industry. Here, prefabricated optical fibers are used in order to assemble flexible circuits.

These days, flexible printed circuit boards are of four types, based on their functions. These are printed circuit, lead line, connectors and integration function system. Here, the flexible circuit connector comes with an insulated housing mounted on to the rigid flex circuit board.

There are basically three materials that comprise flexible circuits. They are the base material, bonding adhesive and metal foil.

The base material or flexible polymer film forms the basis of the laminate by providing the most basic electrical and physical properties of the flexible circuit. Most flexible films range from 12 µm to 125µm (1/2 mil to 5 mils) in thickness, though thinner and thicker are both possible. Other base materials used include polyester (PET), polyethylene napthalate (PEN), polyimide (PI), Polyetherimide (PEI), and several fluropolymers (FEP) and copolymers.

Bonding adhesives are used as glue to make a laminate. These are usually polymer in nature. Like base films, adhesives too come in a variety of thicknesses.

Lastly, metal foil is used as a conductor of a flexible board. Circuit paths are usually drawn from this material. Metal foils too come in a wide variety of thicknesses from which a flexible circuit can be made. The metal most used here is copper—in fact, it is used in a majority of flexible circuit applications. This is because copper has very good attributes in its electrical and physical performance and also presents a very good balance of cost. This makes Flexible Circuit Sales the clear choice of manufacturers.

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Flexible Circuit Sales is the author of this article on Flexible Circuit. Find more information about Flex Circuit here.