Research on a new three proofing technique for the electric meter industry

The operational environment of industrial electronic products is more rigorous than that of household electronic products. Three Proofing (moisture proofing, salt spray proofing, and fungus proofing) has become an important topic in the electronics industry. As the core component of electric equipment, the PCBA (Printed Circuit Board Assemblies) needs extra protection. PCBA surface coating is widely used in the electric meter industry. The voltage sampling circuit and the current sampling circuit are the core parts of the electric meter, which are more sensitive to the influence of moisture, salt spray, and fungus. The traditional surface coating method comes into effect on Three Proofing to some extent, but it also takes some unfavorable factors. A new Three Proofing technique is proposed via the special treatment of solder paste. Anti crack resin and other components are added to the solder paste in a certain proportion. During Reflow Soldering Process, the resin melts and adsorbs on the surface of the solder joint, which forms a protective layer for the solder joint. Reliable experimental verification shows that the proposed technology not only has the function of the Three Proofing, but also solves the unfavorable factors of the traditional process. This provides a new feasible solution for Three Proofing of the electric meter industry.