What conditions must be met for PCB circuit board soldering?

Soldering is the most important process in PCB circuit board manufacturing, and it plays a decisive role in the quality of the circuit board.

So, what conditions must be met for PCB circuit board soldering?

1. The components has good solderability
Solderability refers to the properties of an alloy that forms a good bond between the metal material to be soldered and the solder at an appropriate temperature. 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 components must be kept clean
Even components with good solderability, due to storage or contamination, may produce oxide films and oil stains that are harmful to infiltration on the surface of the components. Be sure to remove the dirty film before soldering, otherwise the soldering quality cannot be guaranteed.

3. Use proper flux
The function of the flux is to clean out the oxide film on the surface of the components. Different soldering processes should choose different fluxes. When soldering precision electronic products, in order to make the soldering reliable and stable, usually use rosin-based flux.

4. The components should be heated to an appropriate temperature
When soldering, the function of heat energy is to melt the solder and heat the soldering object, so that the tin and lead can obtain enough energy to penetrate into the eutectoid on the surface of the soldered metal to form an alloy. If the soldering temperature is too low, it is easy to form a pseudo solder; if the soldering temperature is too high, the solder will be in a non-eutectic state and the quality of the solder will decrease.

5. Appropriate soldering time
Soldering time refers to the time required for physical and chemical changes in the entire soldering process. It includes the time for the soldered metal to reach the soldering temperature, the melting time of the solder, the time for the flux to function, and the time for the formation of metal alloys. When the soldering temperature is determined, the appropriate soldering time should be determined according to the shape, nature, and characteristics of the soldered components.