The selection of Solder Paste is critical in SMT processes. Leaded Solder Paste was widely used in early stages due to its low melting point and good fluidity, but as environmental regulations have become stricter, lead-free solder paste has gradually become the mainstream choice.

In actual production, it has been found that leaded solder paste has stronger wettability in high-temperature zones, making it particularly suitable for soldering high-density PCB boards. However, its lead content poses potential risks to the environment and human health, leading more and more enterprises to switch to lead-free solder paste.

Although lead-free solder paste is environmentally friendly, its melting point is generally higher than that of leaded solder paste, imposing higher requirements on the Reflow Soldering temperature profile. If temperature control is improper, issues such as cold solder joints or incomplete solder joint formation are likely to occur.

In procurement decisions, a comprehensive judgment must be made by considering product type, customer requirements, and cost control. For example, consumer electronics products tend to use lead-free solder paste to meet environmental standards, while industrial equipment may still adopt leaded solder paste due to performance priorities.

The storage conditions of solder paste are equally critical. Whether leaded or lead-free, solder paste must be protected from direct sunlight and high-temperature environments; otherwise, oxidation or deterioration will be accelerated, affecting printing performance.

In practical applications, it is recommended to verify solder paste performance through small-batch trial production. Especially when changing brands or models, printing parameters and reflow soldering profiles should be adjusted simultaneously to ensure process stability.

For post-soldering defects such as bridging and voids, troubleshooting should be conducted from multiple aspects including solder paste deposition volume, stencil aperture size, and reflow soldering temperature distribution, rather than simply attributing the issues to the solder paste itself.

When selecting solder paste, decisions should be based on actual production data rather than solely relying on theoretical analysis. Only through continuous optimization can a high-quality, low-cost soldering process be achieved.