The pollution in PCBA processing originates from various sources, primarily from the assembly process, especially the soldering process. These sources of contamination include:
- Components and PCBs themselves may introduce contamination or oxidation, affecting the surface of the PCBA.
- During manufacturing, solder paste, flux, solder wires, and other materials used in soldering processes can leave residues on the surface of the PCBA, constituting the primary source of pollution.
- Hand soldering processes can leave fingerprint marks, while wave soldering processes may leave wave solder footprints and marks from soldering fixtures or trays. These processes may also introduce other types of pollution, such as adhesive residues from sealing compounds, high-temperature adhesive residues, fingerprints, and airborne dust.
- Contaminants from the work environment, including dust, water, solvent vapors, smoke, fine organic particles, and charged particles from static electricity, can also adhere to the surface of the PCBA.
The above-mentioned pollutants mainly stem from the assembly process, particularly the soldering process.
