Discussion on welding method of FPC flexible cable

With the development of electronics towards miniaturization and miniaturization, the difficulty of manually welding FPC flexible cables has also increased. Slight carelessness in welding can damage components or cause poor welding, so a good welding method for FPC flexible cables is particularly important.



"When the solder is a tin-lead alloy and the welding surface is copper, the solder first wets the welding surface. With the occurrence of wetting, the solder gradually diffuses towards the metal copper, forming an adhesive layer on the contact surface between the solder and the metal copper, making the two firmly bonded. Therefore, solder is completed through three physical and chemical processes: wetting, diffusion, and metallurgical bonding.". "To achieve a good solder joint, the object to be soldered must have a surface that is completely free of oxide layers. However, once the metal is exposed to air, an oxide layer can be formed, which cannot be cleaned with traditional solvents. At this time, it is necessary to rely on the chemical action of the flux and the oxide layer. After the oxide layer is removed by the flux, a clean surface of the object to be soldered can be combined with solder.". The specific operation steps of soldering iron welding can be divided into five steps, known as the five step engineering method. To obtain good welding quality, it is necessary to strictly follow the steps. Step by step welding is one of the keys to obtaining good solder joints. Before welding FPC flexible cable, observe whether each welding point (copper sheet) is smooth, clean, oxidized, etc. When welding items, it is necessary to look carefully at the welding points to avoid short circuits caused by poor soldering of FPC flexible cable lines. After using the soldering iron, the remaining tin from the soldering iron head should be wiped off on a sponge.