In wave soldering, the main process materials used are flux and solder.

　　1. The application of flux can remove oxides from the welding surface, prevent reoxidation of the solder and welding surface during welding, reduce the surface tension of the solder, and help transfer heat to the welding area. Flux plays a crucial role in controlling welding quality. At present, the most commonly used flux for wave soldering is non cleaning flux, and there are the following requirements when selecting flux:

　　(1) The melting point is lower than that of solder;

　　(2) The infiltration diffusion speed is faster than that of melted solder;

　　(3) The viscosity and specific gravity are smaller than those of solder;

　　(4) Stable storage at room temperature.

　　2. Quality control of solder

　　Tin lead solder continuously oxidizes at high temperatures (250 ℃), causing a continuous decrease in the tin content of the tin lead solder in the tin pot, deviating from the eutectic point, resulting in poor flowability, and quality issues such as continuous soldering, false soldering, and insufficient solder joint strength. The following methods can be used to solve this problem:

　　(1) Add redox agents to reduce oxidized SnO to Sn, reducing the generation of tin slag.

　　(2) Add a certain amount of tin before each welding.

　　(3) Use solder containing antioxidant phosphorus.

　　(4) Using nitrogen protection to isolate the solder from the air, replacing ordinary gas, thus avoiding the generation of scum.