1. Overview of FPC flexible printed circuit board
Printed circuit boards (PCBs) are the basic products of the electronic industry. They are widely used in communication equipment, computers, automotive electronics, industrial equipment and various household appliances. Their main functions are supporting circuit elements and interconnection circuit elements. FPC Flexible Printed Circuit Board (FPC) is one of the main types of printed circuit boards. According to the structure of FPC flexible printed circuit board, according to the number of conductor layers, it can be divided into single-sided flexible printed circuit board, double-sided flexible printed circuit board and multi flexible printed circuit board.
2. Main raw materials (physical and chemical materials) for FPC flexible printed circuit board manufacturing
(1) Flexible copper clad laminate (FCCL): According to the difference between one side covered with copper foil or two sides covered with copper foil, it is called one-sided copper clad laminate and two-sided copper clad laminate. According to the difference between copper foil and base film, it is called glued copper clad laminate and non-glued copper clad laminate. Polyimide (PI), polyester (PET), polyethylene 2,6 naphthalate (PEN:), liquid crystal polymer (LCP) and other polymer films are commonly used as substrates for flexible copper clad laminates. Copper clad panels are mainly responsible for conducting, insulating and supporting functions on the entire printed circuit board. The performance, quality, processability, manufacturing cost and manufacturing level of printed circuit boards depend largely on the performance of copper clad laminates.
(2) Covering film: It is composed of organic film and adhesives. The function of covering film is to protect the conductor part of the completed flexible circuit. There are different types and thickness specifications of base film and adhesives. Some FPC flexible printed circuit boards are coated with flux instead of covering film to reduce cost.
(3) Bonding film: It is formed by pouring binder on both sides or one side of a base material film. There are also pure binder films without a base material. The binder film has different types and thickness specifications of binders. Adhesive film is used for interlaminar bonding and insulation of multilayer plates.
(4) Copper foil: There are electrolytic copper foil and calendered copper foil, as well as different thickness specifications of copper foil. Copper foil is used for two surface conductor layers in the production of multilayer printed circuit boards.
3. Processing process of FPC flexible printed circuit board
Sheet by Sheet, similar to the rigid plate one by one intermittent step processing.
FPC flexible printed circuit boards are processed with the same process and equipment conditions as rigid boards. There are sheet-by-sheet processing in the form of processing: Sheet by Sheet, similar to rigid plate processing in a intermittent step-by-step manner, or Roll to Roll, is a continuous processing of a roll of substrate.