Conditions of soldering in circuit board welding
1. Weldments should have good weldability.
The characteristic of metal surface infiltrated by molten solder is called solderability.
Some metal materials have good weldability, but some metals such as molybdenum, chromium, tungsten, etc. have very poor weldability. Even the metals with good solderability, such as red copper, brass and so on, are easy to produce oxide film on their surface. In order to improve the solderability, surface tin and silver plating are usually used.
2, use the appropriate flux.
The function of the flux is to remove the oxide film on the surface of the weldment and reduce the surface tension of the melted solder to facilitate wetting. Different weldments should be selected for different weldments and different welding processes. It is difficult to solder materials such as nickel-chromium alloy, stainless steel and aluminum without special flux.
3. The surface of the weldment must be clean.
Due to long-term storage and contamination, welding parts may produce oxides and oil stains on the surface. Therefore, the surface must be cleaned before welding to ensure welding quality.
4, heating to the right temperature.
During welding, solder is melted and the weldment is heated to the temperature of molten solder. Only at sufficiently high temperatures can the solder be sufficiently infiltrated and diffused to form an alloy bonding layer.