Dispensing Solder Paste and dot solder paste cannot be used by simply replacing solder paste; equipment compatibility, solder climbing capability and residue characteristics must be considered. For example, LFP-JJY5RQ-0307T4 has a measured solder climbing rate of 98.7% on QFN0.4mm pitch, while 5RTS-0307 with the same powder particle size has a stable solder climbing rate between 76% and 89%. The difference in Flux activity between the two is directly reflected in the side wetting angle after reflow, with the former averaging 22° and the latter around 35°. During production line changeover, it was found that if 5RNTT is used for the BT module of mobile phone motherboards, its 100~200ppm ROL0 halogen level combined with 00507B2N alloy powder results in a void rate consistently below 2.3% in X-ray inspection, which is 0.8 percentage points lower than the conventional 305 series.

The selection of dot solder paste cannot only focus on the melting point, but also pay attention to the synergy between the particle size distribution of alloy powder and the viscosity of the rosin carrier. For example, LFP-JJY5RLJ-305 has a dispensing consistency of ±1.2mg/shot in jet valve dispensing, while the ordinary T4 powder 8MQP has a fluctuation of ±2.8mg under the same screw valve. The fundamental reason is that 5RLJ uses T6-grade narrow distribution 00507BN powder and the rosin softening point is increased to 68℃, avoiding stringing and trailing caused by a sudden drop in viscosity after the valve body heats up. For Domestic Solder Paste to pass customer Audit, the halogen data must be firmly recorded in the report. The 5RR series has a measured 0ppm halogen and full REACH compliance. During the factory audit of a German automotive lighting manufacturer, three batches were sampled on the spot, and all ICP-MS results were ≤0.8ppm, with a shear force attenuation of only 4.1% after 2000 thermal cycles.

Water-washable dispensing solder paste must be verified for cleaning compatibility. LFP-JJY5RW1A-4258 is used on aluminum nickel-plated heat sinks, and the ionic contamination value after pure water rinsing is <0>10. Low-temperature dispensing solder paste must strictly control the temperature window. 5RG-In52Sn48 can complete soldering after holding at 130℃ for 60 seconds, but if it enters the nitrogen protection zone in advance, the increase in In element vapor pressure will instead lead to more solder balls. By adopting a stepped temperature rise, first holding at 110℃ for 45 seconds in the air zone then switching to nitrogen, the solder ball rate is reduced from 1.7‰ to below 0.3‰.

The cost advantage of domestic solder paste lies not in unit price but in comprehensive yield. The LFP-JJY5RQ series increases the first-pass yield from 92.4% to 96.8% in mass production of LED driver boards, mainly due to its ROL1-level halogen control and the sphericity of T4 powder >92%, with a printing release rate 3.6 percentage points higher than that of an imported brand. When performing dot soldering processes, do not blindly believe in "high activity". LFP-JJY5MA-0107 performs more stably on large-pitch pads of lighting power supplies, because its rosin content is finely adjusted to 14.3% with a gentle volatilization gradient. The area of carbonized residue after reflow is 41% less than that of 5RQ, and the AOI false alarm rate drops by 27%.