Evaluating Domestic Solder Paste brands cannot rely solely on parameter tables; it must be verified across the full SMT production line process of actual printing, reflow, and post-soldering inspection. For example, the 8MQP/5RQ series achieves a measured solder wetting rate close to 100% on QFN 0.4mm pitch components, provided the stencil aperture ratio is designed at 1:1.05 and the squeegee pressure is stably maintained at 6.5±0.3kg. Under the same conditions, the 8MTSP/5RTS, which is also labeled as high-activity, has a solder wetting rate falling in the 70%–90% range. The main cause of fluctuation is that after its halogen content is reduced to below 500ppm, the Flux volatilization gradient becomes steeper, so even a slight temperature difference in the preheating section affects wetting and spreading.

Communication motherboards are extremely sensitive to residue transparency and ionic contamination. The 8MNTTP/5RNTT uses 00507BN/T5 fine powder with ROL0-grade halogen controlled at 100–200ppm, leaving almost no white residue under a microscope after reflow. However, it produces slight solder balls when used on LED lighting boards. The reason is that its rosin system has an increased tendency to carbonize when the dwell time in the 235℃ soaking zone exceeds 90 seconds. In this case, switching to the 8MA series paired with SC07/T4 powder is more stable, as its ROL1-grade halogen content is slightly higher but its thermal decomposition curve is gentler.

Automotive electronic lighting boards require a void rate below 5%. The 8M9P/5RR achieves zero halogen while keeping voids within 3.2%, the key being that the ratio of its 305 alloy powder to special carrier reduces the surface tension of the molten state by 12%. However, this formulation has poor dispensing consistency when used with jet valves, so it must be switched to the 5RLJ laser-specific Solder Paste. The latter uses 00507B2N/T6 powder paired with <500ppm> water-washable solder paste, which cannot be made usable simply by adding a water-soluble component. The 8MW1P/5RW1 leaves the board surface as clean as new after cleaning on aluminum nickel-plated heat sinks, but when the 8MW5/5RW5 is used for stainless steel welding, if the cleaning water temperature is below 42℃ or the pH value deviates from 7.8–8.2, grayish-white salt stains will precipitate at the weld edge. This is related to the precipitation of Bi in its SC07+Sn42Bi58 composite powder under a weakly alkaline hydrolysis environment.

For ultra-low temperature scenarios such as welding flexible FPC reinforcement sheets, the 5RG uses In52Sn48 alloy with a melting point of only 118℃. However, its T7-grade ultra-fine powder has strong adsorption on the inner wall of dispensing needles, so it must be paired with a nozzle with an inner diameter of 0.18mm or more and the dispensing air pressure increased to 0.6MPa to avoid clogging. The same series 5RLJB uses Sn42Bi58, which has a wider reflow window at 160–185℃, high tolerance for furnace temperature fluctuations, and is suitable for production lines retrofitted with old Reflow Soldering equipment.