How many parts does the fpc structure generally consist of?

嘉立创FPC

How many parts does the fpc structure generally consist of? [Copy link]

The composition of FPC mainly includes conductive layer, insulating layer and adhesive layer, in which the conductive layer is made of copper foil, the insulating layer is mainly realized by coating polyimide film or polyester film, and the adhesive layer is epoxy resin, which is mainly used to fix the conductive layer. The heat resistance and mechanical properties of the FPC substrate depend on the material and thickness of the conductive layer and adhesive layer.

1. Insulation layer

The insulating layer of the FPC substrate is mainly achieved by coating a polyimide film or other insulating materials on both sides of the conductive layer.

The function of the insulation layer is to isolate the conductive layer, prevent short circuit and interference, and provide electrical insulation performance of the circuit board. Common insulation layer materials are polyimide film (PI) and polyester film (PET).

Polyimide film (PI) has good high temperature resistance and can work normally at higher temperatures, usually withstanding temperatures ranging from -200 degrees Celsius to +300 degrees Celsius.

Compared with polyimide film (PI), polyester film (PET) is much cheaper, but its dimensional stability and temperature resistance are poor, and it is not suitable for SMT mounting or wave soldering. It has been gradually replaced by polyimide film (PI). Common polyimide film (PI) thicknesses include: 1/2mil, 1mil, 2mil, etc.

2. Conductive layer The conductive layer of the FPC substrate is generally made of copper foil, which has good conductivity and processability and can provide the conductive path required by the circuit board. Depending on the specific application requirements, the thickness of the conductive layer can vary, and common thicknesses include 1/3 oz, 1/2 oz, 1 oz, etc.

3. Adhesive layer

The adhesive layer of the FPC substrate is what we often call the glue layer. It is made of epoxy resin and has a thickness of 15um and 25um. Its main function is to fix the conductive layer and improve the insulation strength and mechanical properties. However, the glue is prone to aging, which will reduce the temperature resistance and bending performance, and the cost is relatively low.

JLC's FPC substrate is copper foil + PI + copper foil, which is directly made by high-temperature hot rolling. Its temperature resistance is more than 30 degrees higher than that of conventional adhesive substrates, the number of bending times is increased by 50%, and the overall weight is reduced by 10%.