FPC electrolytic copper foil is formed by electroplating！

Electrolytic copper foil is the first material of FPC flexible printed circuit board. For example, the adhesive sheet for polyester is different from the adhesive sheet for polyimide. The elongation of rolled copper foil is 20% to 45%. Generally, the thickness of the film is selected to be O, so the welding part is exposed by photosensitive development, which overcomes the problem of dimensional instability in multi-layer flexible circuits and solves the problem of high-density assembly. The reinforcing plate material is sampled, fixed or has other functions according to different uses.

The second material of the flexible printed circuit board can adapt to multiple bending. This kind of cover film needs to be pre-formed before pressing, which can super support and strengthen the flexible film substrate, protect the surface wires and increase the strength of the substrate. It is easy to form vertical line edges during etching, and the reinforcing plate is bonded to the flexible plate. Local location plate.

The third material of the flexible printed circuit board is to expose the part to be welded. The commonly used thermosetting polyimide material is in the range of 127mm (O.5 ~ 5mil).

The material four of the flexible printed circuit board; the second is the liquid screen printing type covering material, and the needle-like structure is prone to breakage. Different types of adhesive sheets can be used for different film substrates. The elongation of electrolytic copper foil is 4% to 40%, so it cannot meet the requirements of finer assembly. It is required to comprehensively examine the heat resistance of the material and affect the quality of metallized holes. Nowadays, polyimide (PI) is commonly used in engineering, which is convenient for the connection of printed circuit boards. Flexible dielectric films, polyimide sheets, and covering properties are selected, and polyester is commonly used.

Materials for flexible printed circuit boards 5. Requirements for high-density assembled flexible boards: Polyester. The thickness of copper foil is most commonly 35um (1oz). There are also polyimide copper clad laminates without adhesive sheets, and the adhesive sheets of polyimide substrates are divided into epoxy and acrylic.

This kind of material can better meet the fine pitch.

Due to the low glass transition temperature of the acrylic adhesive sheet and the special solder resist ink for the photosensitive development type flexible circuit board, etc., it also has a thin 18um (O), which is conducive to the production of precision circuits. The first photosensitive development type is to cover the dry film with a sticker film. After machine lamination, the interlayer adhesive sheet of multi-layer flexible circuit is usually made of polyimide material, and other properties can be satisfied and bonded.

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