is mainly used to wet the base metal during the welding process, if the material being welded is not wet enough. The entire welding cannot be performed. It's like putting grease on a material, and the material cannot be wetted by water. Because the oil on the surface of the material cannot be mixed with water, that is, the wettability is not enough, and the two cannot be combined. At this time, we will apply the detergent on the material, the detergent will remove the oil stains on the surface of the material, and the water will fuse with the material to cause wetness. In the SMT soldering process, the role of the Solder flux is equivalent to the role of cleaning. The surface oxide of the material to be welded is removed and the surface is wetted. On the other hand, the Solder flux is melted during the soldering process to form a liquid, which covers the surface of the circuit board, which can prevent the circuit board at high temperature from being oxidized twice by oxygen in the air.
Solder flux can greatly reduce the surface tension of molten solder paste. This surface tension will affect the quality of solder paste soldering. Adding Solder flux or solder paste to solder paste, its function is to reduce the surface tension of the material. On the surface of the molten solder paste, the tension will prevent the normal progress of its welding. When the Solder flux is melted and covered on the surface of the soldering material, the surface tension of the molten solder paste liquid can be reduced. The wettability of the solder paste liquid can be significantly improved. The above is the role of the Solder flux introduced for you.
We live in an environment full of nitrogen and oxygen, because the air contains a lot of oxygen, so many substances in this environment will be oxidized by the oxygen in the air. Circuit boards that are common in the electronics industry, although There are various measures to prevent oxidation such as vacuuming and filling with nitrogen, but the surface of the circuit board with the welding position will inevitably come into contact with the oxygen in the air and be oxidized. If we need to solder electronic components to the circuit board, the oxidized metal surface oxide on the circuit board must be removed in advance, otherwise it is impossible to achieve metallurgical bonding and achieve the connection between electrical performance and structural performance.