Poor stencil release is rarely caused by a single factor, but rather the combined effect of Solder Paste rheological properties, stencil aperture geometric accuracy, squeegee pressure and speed matching, and environmental temperature and humidity fluctuations. Especially when the production line switches to 0.4mm pitch QFN or 0.3mm pitch BGA, conventional medium-activity solder paste with insufficient T4 powder content is highly prone to issues such as edge solder bridging, aperture residue, and top depression of the paste after release. It was once observed on a tablet customer's production line that after switching the same DEK printer to LFP-JJY5RQ-0307T4, the complete release rate of stencil release solder paste increased from 92.3% to 98.7%, with no obvious stencil sticking after 2000 consecutive prints. The key lies in its 0307 alloy powder (Sn99Ag0.3Cu0.7) with a melting point of 221–227℃, paired with T4 grade (D50=15±2μm) narrow-distribution spherical powder, which makes the shear thinning behavior of the paste more controllable. Meanwhile, ROL1 grade halogen control (single item <900ppm> compared to LFP-JJY5RNTT-0307T4, this model further compresses halogen to the 100–200ppm ROL0 level, and introduces trace Bi/Ni synergistic modification, demonstrating superior stencil release solder paste release consistency in high-density BGA (0.65mm pitch) printing for communication modules. Under a microscope, no visible residue was observed on the bottom of the stencil after release, and the solder fillet climb height after reflow reached 92% of the pin height. In contrast, conventional T3 powder solder paste in such scenarios often experiences alternating local solder beading and aperture clogging. The root cause is that T3 powder with D50=25±3μm leads to a high paste yield value, which easily causes micro-tearing rather than smooth peeling at the moment of stencil release under 25℃/60%RH conditions.

In response to the stringent void rate requirements of automotive electronics customers, the halogen-free + REACH certified version of LFP-JJY5RR-0307T4 achieved an average void rate <3> on LED headlight boards (Al substrate + OSP copper surface). Although the water-washable LFP-JJY5RW1-0307T4 sacrifices some wetting ductility, it exhibits unique value in nickel-plated aluminum fin soldering for heat sinks. Its ORH1 water-washable grade corresponds to enhanced polarity of rosin resin side chains, which not only ensures stencil release solder paste does not stick to the stencil, but also ensures post-solder residue can be completely removed by pure water at 45℃ in 30 seconds, avoiding the nickel layer corrosion risk caused by traditional solvent cleaning. Measured on the same PCB after 500 consecutive prints, the stencil tension attenuation was only 0.8N/cm2, far below the industry average of 2.3N/cm2, indicating that this Domestic Solder Paste's ability to suppress stencil metal fatigue has approached the level of top-tier imported products.