Flux is an important auxiliary material in PCBA circuit board welding. The quality of flux will directly affect the quality of PCBA circuit board welding. Now FASTPCBA will give you an analysis of why flux is so important.

1. The principle of flux welding

The fact that the flux can take on the role of welding is the result of mutual diffusion, dissolution, wetting, etc. after the distance between the metal atoms is close. In addition to the activation performance of removing oxides and pollutants, the flux needs to meet the requirements of non-corrosiveness, insulation, moisture resistance, stability, harmlessness, and purity. Generally speaking, its main components are active agents, film-forming substances, additives, solvents and so on.

2. Remove oxides on the surface of the welded metal

In the normal air environment, there are often some oxides on the surface of the pad metal. These oxides will affect the wetting of the solder during the soldering process and thus affect the soldering process and soldering results. Therefore, the flux needs to be able to reduce the oxides. , The welding of PCBA processing can be carried out normally.

3. Prevent secondary oxidation

During the soldering process of PCBA processing, heating is required. However, the metal surface will rapidly oxidize due to the increase in temperature during the heating process. At this time, flux is needed to prevent secondary oxidation.

4. Reduce the tension of molten solder

Due to the physical form, the surface of the molten solder will have a certain tension, and the surface tension will cause the speed of the solder to flow to the surface to be soldered, which will affect the normal wetting during the soldering process, and the role of the flux at this time is to reduce The surface tension of liquid solder significantly improves the wetting performance.

The above is the analysis of why the flux is so important for PCBA circuit board soldering. In order not to affect the function and life of the circuit board, the PCBA board after using the flux needs to be cleaned in time for the residue on the surface.