No-clean PCBA Soldering Materials are not truly "no-clean" in mass production; instead, the cleaning step is moved upstream to the formulation design stage of Solder Paste and Flux. The JiajinYuan JY-826 water-washable formulation adjusts the ratio of organic acid activators and the proportion of low-boiling-point solvents, achieving a natural volatilization rate of 92.3% after reflow. The remaining residues can be completely dissolved by pure water at 45°C within 30 seconds. This data comes from three consecutive months of SPC monitoring records at an automotive ECU production line in Shenzhen.

Hard Constraints for Ionic Residue and Surface Insulation Resistance

The core cleanliness indicator for PCBA soldering materials is the total residual amount of chloride ions, bromide ions, and organic acid salts. JiajinYuan JY-826 blends nonylphenol polyoxyethylene ether nonionic surfactants with citric acid derivatives, maintaining wettability while reducing ionic residue to 0.47μg/cm² (IPC-TM-650 2.3.25 method). Combined with flying probe testing, it shows board surface SIR > 1×10¹¹Ω@85°C/85%RH/168h, fully meeting the long-term reliability requirements of automotive-grade AEC-Q200 for PCBA Soldering Materials.

The Water-Wash Process Window Must Match the Physical Limits of the Equipment

If the spray pressure of a fully automatic water washer exceeds 0.25MPa, it will cause displacement of 0201 resistors or deformation of QFN pins. The JiajinYuan formulation controls the molecular weight of the water-soluble film-forming agent within the range of 800±50Da, maintaining the cleaning solution viscosity at 1.8cP at room temperature. This ensures spray penetration while avoiding liquid film retention between fine-pitch pads. Actual measurements at a power module factory in Dongguan show that under this parameter combination, the water-wash yield is stable at 99.91%, an increase of 0.37 percentage points compared to the previous generation.

No-Clean and Water-Wash Are Not an Either-Or Choice but a Dynamic Switch

The same PCBA soldering material may experience changes in residue morphology across different batches due to variations in the oxidation level of tin powder. JiajinYuan adds a trace amount of benzotriazole corrosion inhibitor to JY-826. When the oxide film thickness on the incoming tin powder surface exceeds 8nm, it automatically enhances water-soluble complexing ability. This allows factories to flexibly switch between no-clean mode (only wiping key areas with isopropyl alcohol) and full water-wash mode according to order requirements without changing the solder paste. An industrial control motherboard factory in Suzhou has incorporated this feature into Clause 4.2 of its IQC incoming inspection standards.

Cleanliness Verification Must Return to the Real Assembly State

Testing solder paste residue alone is meaningless; ionic chromatography must be retested on the complete machine after ICT testing, conformal coating application, and high-low temperature cycling. JiajinYuan provides a matching PCBA soldering material residue sampling kit, including 0.45μm nylon filter membranes and pre-calibrated Na⁺/Cl⁻ mixed standard solutions. A medical device factory in Shenzhen used this kit to discover residue accumulation at the bottom of a certain batch of BGAs, which was traced to a 0.012mm out-of-tolerance deviation in stencil aperture dimensions rather than a problem with the formulation itself.