Flux

Flux is a chemical auxiliary used in soldering and welding to create strong, clean joints. It works by removing oxides and contaminants from metal surfaces, preventing re-oxidation during heating, and improving wetting so that the solder can flow evenly and bond properly.

In electronics manufacturing, flux is used in solid, liquid, or paste form, often integrated into solder wire or solder paste. Common types include rosin-based fluxes for electronics, organic acid fluxes that require cleaning, and so-called no-clean variants that leave minimal residue. Without flux, there is a risk of poor adhesion, oxidized surfaces, and weak solder joints that can lead to operational failures.

When sourcing flux, it is important to consider the type of flux, compatibility with lead-free or leaded soldering, and relevant standards such as IPC J-STD-004.