What are the Requirements for PCB Soldering?

Soldering is an important process in the PCB processing, which plays a decisive role tin the quality of the PCB. So, what are the requirements for PCB soldering?

1. Good solderability

Under certain soldering conditions, the ability to easily obtain good welded joints is called solderability. In order to improve the solderability, measures such as tin plating and silver plating on the surface can be used to prevent oxidation of the material surface.

2. The surface of the soldering lug is clean

In order to achieve a good combination of soldering tin and weldment, even if the solderability is good, the surface of the soldering lug must be clean. Due to the long-term storage and pollution, the surface of the soldering lug may produce harmful oxide film, oil stains, etc. So, please be sure to clean the surface of the soldering lug before soldering, otherwise the soldering quality cannot be guaranteed.

3. Suitable flux

The function of the flux is to remove the oxide film on the surface of the weldment. Different soldering technology should choose different fux. Generally, when soldering precision electronic products such as PCB, in order to make the soldering reliable and stable, the flux mainly based on rosin is usually used.

4. Proper temperature

During soldering, the function of heat energy is to melt the soldering tin and heat the welding object, so that the tin and lead can obtain enough energy to penetrate into the crystal lattice on the surface of the welded metal to form an alloy. When the soldering temperature is too low, the alloy cannot be formed, and it is easy to form a Pseudo Soldering. When the soldering temperature is too high, the solder will be in a non-eutectic state, which will accelerate the decomposition and volatilization of the flux, and reduce the quality of the solder.

5. Suitable soldering time

Soldering time refers to the time required for physical and chemical changes during the entire soldering process. When the soldering temperature is determined, the appropriate soldering time should be determined according to the shape, nature, and characteristics of the welded part. If the soldering time is too long, it is easy to damage the welding parts of the components; if the soldering time is too short, the soldering requirements will not be met.