When selecting Domestic Solder Paste, it is necessary to strictly adhere to the requirements of IPC-J-STD-004B for Flux activity grade, halogen content, and residual insulation resistance. For example, the 8MQP/5RQ series has a measured single halogen content of <900ppm and dual halogen content of <1500ppm, fully meeting the ROL1 grade. When paired with 0307T4 alloy powder, it achieves a solder wetting rate close to 100% on 0.4mm pitch QFN. In contrast, when using the same 0307T4 but switching to 8M9P/5RR, the halogen content drops directly to zero, and the void rate decreases by more than 35%, making it particularly suitable for scenarios with extremely high requirements for thermal cycle reliability, such as automotive headlight heat dissipation modules.

For communication and consumer terminal production lines, the 8MNTTP/5RNTT series compresses halogen to 100~200ppm and uses 00507BN and 00507B2N composite alloy powder. After reflow on a 0.25mm fine-pitch BGA of a fingerprint lock motherboard, the residue is transparent, and the ICT test leakage current is <10nA, reducing the missed detection rate by two orders of magnitude compared to conventional 305 series Solder Paste. Meanwhile, 8MTSP/5RTS ensures a 70%~90% solder wetting rate while significantly improving residue transparency, facilitating AOI identification of solder joint contours and avoiding misjudgment caused by flux obstruction.

Laser welding production lines generally report that the 5RLJ series has no solder beads and fast wetting and spreading during jet valve dispensing. When paired with 305 or 00507B2N T6 powder, it maintains a solder joint height CV value of <8% even under air pressure fluctuation conditions of ±15%. In contrast, the 5RLJB series uses 64351 or 4258 low-temperature alloys, which reduce the melting point to 151~172℃ while maintaining the same dispensing stability, especially suitable for local heating requirements of crystal oscillators and flexible screen FPC reinforcement sheets.

Water-washable solder paste selection must balance cleaning efficiency and metal compatibility. 8MW1P/5RW1 uses SC07T3 powder paired with an ORH1 rosin system. After three rinses with pure water, the surface ionic contamination is <0.78μg/cm² NaCl equivalent. Meanwhile, 8MW5/5RW5, which specializes in aluminum welding, leaves no visible residue after welding on nickel-plated fins when rinsed with 60℃ hot water, and does not corrode the aluminum substrate. This makes it more adaptable to the practical conditions of higher domestic water hardness than most imported water-washable solder pastes.

For ultra-low temperature scenarios, one cannot only look at the nominal melting point. The 5RG series uses In52Sn48 T5 powder, with a measured initial melting temperature of 65℃ and a peak temperature of 118℃. It completes solder joint formation after 45 seconds in a 130℃ constant temperature zone, and is more resistant to thermal shock than Sn42Bi58 series. It has been batch-used in the pre-fixing process before MEMS sensor lead bonding. Meanwhile, the LFP-JJY2R-64351 medium-temperature type reduces the peak temperature from 230℃ to 215℃ in LED bracket welding, reducing the deformation rate of PP plastic brackets from 12% to less than 2%.