Rosin flux usually a mixture of the main component, is to ensure the smooth progress of auxiliary materials for the welding process. The main role is to remove solder flux and solder base metal oxide is (material) surface, the metal surface to achieve the necessary cleanliness. It prevents re-oxidation of the surface of welding, reducing the surface tension of the solder and improve the weldability. Flux performance will directly affect the quality of electronic products.

Flux has the following features

1) Wetting (lateral flow): also known as infiltration, refers to the molten solder on the metal surface to form a uniform, smooth, continuous and attached to a solid solder layer. Infiltration mainly determined by the surface tension of the cleanliness of the weld surface and solder.

2) diffusion (vertical flow): With the molten solder wetting solder surface diffusion phenomenon also occurs inside the solder to a solid metal diffusion phenomenon.