The role of SMT processing and soldering flux in Yantai

In order to achieve a better no-clean effect in SMT processing in Yantai, two parameters must be strictly controlled: the solid content of the flux and the application amount. The key active ingredient in flux is rosin, which decomposes at around 280°C, so the temperature of the solder pot should not be too high. Flux is a chemical substance that promotes soldering. In soldering, it is an indispensable auxiliary material, and its role is extremely important. In SMT patch processing, the physical properties of flux mainly refer to characteristics related to soldering performance, such as melting point, boiling point, softening point, glass transition temperature, vapor pressure, surface tension, viscosity, and miscibility. The functions of flux include the following four aspects:

1. It should have relatively good thermal stability. Generally, the thermal stability temperature should not be less than 100°C.

2. The flux should have an appropriate activation temperature range. It should begin to take effect before the soldering material melts, and during the soldering process, it should effectively play its role in removing oxide films and reducing the surface tension of the liquid soldering material. Its melting point should be lower than that of the soldering material, but the difference should not be too large.

3. The residue after soldering should be non-corrosive and easy to clean. It should not precipitate toxic or harmful gases. It must meet the electronic industry's requirements for water extract resistivity and insulation resistance. It should not absorb moisture or promote mold growth. It should have relatively stable chemical properties and be easy to store.

4. The density of the flux should be lower than the density of the liquid soldering material. This allows the flux to spread evenly over the metal surface to be soldered, forming a thin film covering the soldering material and the metal surface. This film effectively blocks air and promotes the wetting of the base metal by the soldering material.

The above covers today's topic regarding the role of flux in SMT processing. This concludes today's content. If you have any other questions after reading this article, please feel free to consult us.