Analysis Of FPC Connector Knowledge And Product Structure Analysis

Nowadays, with the popularization of SMT technology in the field of electronic products, the application of surface mount connectors has become more and more extensive, and various types of PCBs have corresponding surface mount connectors. From the through-hole (T/H) soldering process to the surface-mount (SMT) soldering process, the terminal arrangement pitch (pitch) of the connector is gradually reduced to 0.8mm and 0.5mm, and the application of the SMT process allows both sides of the PCB Welding electronic components greatly increases the density of components on the PCB. Now all kinds of consumer electronic products have integrated miniaturization, thinness and high performance, using flexible printed circuit boards (FPC) and matching FPC connectors to reduce space, reduce weight, and reduce assembly costs. Accepted by many customers.

1. The function and application scope of FPC connector products

The function of the FPC connector product is to connect the circuit board (PCB) and the flexible printed circuit board (FPC) to realize the mechanical and electrical connection. Today's FPC connectors are mainly used in LCD and LED liquid crystal displays, scanners, digital cameras, game consoles, tablet computers, notebook computers, car theaters and other electronic equipment. FPC connector products are also widely used in audio, digital machines, cameras, car audio, televisions, typewriters, calculators, cash registers, telephones, CD-ROMs, VCDs, DVDs, copiers, printers, wireless instruments and other equipment.

Second, the structure of FPC connector products

The FPC connector can be thinned, and in order to suppress the occupied area of the connector, and seek miniaturization, the connector for high-frequency signal transmission. This connector consists of four parts, which are rubber core, tongue piece, terminal, and soldering piece. , The following is the knowledge explanation of these four parts;

1. The function of the FPC connector rubber core is to protect the terminals, insulate, guide the connection, provide mechanical strength, etc. The manufacturing process of the FPC connector rubber core generally uses an injection molding process, and the material is mostly PA9T material.

The inside of the plastic body of the FPC connector rubber core is an equally spaced sheet-like partition structure, which allows the terminals to maintain a small spacing arrangement and provide a certain retention force after assembly. According to the use requirements of the product, the plastic body must have sufficient strength and toughness, and there must be no warpage deformation before and after SMT welding. In order to meet the requirements of the SMT manufacturing process, the terminal welding area of the entire product is strictly required to have good flatness and coplanarity. Usually the industry standard is 0.10max, otherwise it will lead to poor soldering with the PCB and affect the product. use.

2. The function of the tongue of the FPC connector is to crimp the cable, insulate, guide the connection, provide the strength of the mechanism, etc. The manufacturing process of the tongue of the FPC connector generally uses the injection molding process, and the material is PA10T, PPS.

The tongue parts of the FPC connector are matched with the plastic body. When the FPC is inserted, the tongue parts are used to lock the FPC to maintain a certain contact force, so the parts are required to have sufficient rigidity.

3. The function of the FPC connector terminal is the conductor transmission of electronic signals. The manufacturing process uses a stamping + electroplating process (gold or tinned to improve the soldering ability of the product), and the material uses phosphor bronze C5191.

Generally, there are two ways to design the terminal structure, one is to stamp the flat blanking terminal (abbreviated as: blanking terminal), and the other is to bend and form the terminal after stamping (abbreviation: forming terminal). Since the narrow-sheet female terminal needs to have sufficient elasticity and relatively complicated shape, if the stamping method is adopted, it will cause difficulties in stamping processing, and the forming size and accuracy are not easy to control, so the female terminal usually adopts the forming method.

4. The function of the FPC connector welding piece is component positioning, fixing, increasing strength, etc. The manufacturing process also uses a stamping + electroplating process (gold or tin plating to improve the welding ability of the product), and the material uses bronze C2680.

The soldering piece is used to strengthen the connection between the connector and the PCB, and can avoid damage to the soldering of the terminal and the PCB due to excessive stress on the terminal. After assembly, the soldering piece is required to be consistent with the coplanarity of all terminals. In the FPC connector with a small number of pins, the soldering piece is not a necessary part.