JJY's production line stably outputs 12 tons of Domestic Solder daily. The entire process from high-purity Tin Ingot melting to nitrogen-protected casting is completed in a Class 10,000 cleanroom. The Solder Paste adopts a dual process of three-roll milling + vacuum defoaming to control the metal particle D50=25±2μm. Combined with the self-developed rosin-based Flux system, it achieves continuous printing of 2000 pieces on 0.3mm pitch QFN devices without bridging, with a defect rate of less than 0.12% for insufficient solder.

Solder paste stability directly determines SMT first-pass yield

We found that after the same can of solder paste is stored at a constant temperature of 25℃ for 7 days, if the viscosity attenuation exceeds 12%, it will lead to uneven solder release under the squeegee. However, JJY solder paste has a measured viscosity fluctuation of only ±6.8% after 14 days in an unopened state. This is due to the synergistic ratio of its thixotropic regulator and surfactant, which shortens the shear thinning response time to 0.8 seconds during high-speed printing, corresponding to a volume deviation standard deviation controlled within ±4.3% in SPI inspection.

Solder spattering and icicle formation of Solder Wire must be solved simultaneously

When the preheating zone temperature of wave soldering is set to 110℃ for 0.5mm diameter solder wire, if the flux core moisture content is >0.03%, it will cause micro-explosion at the moment of contact with the solder joint and trigger solder balls. JJY reduces the residual moisture of the flux core to below 0.008% through two vacuum baking processes. Combined with the copper-clad tin structure design, it reduces the surface tension in the molten state by 17%. The measured solder icicle length for devices with 0.3mm pin pitch is <0.15mm.

The thickness of the Solder Bar oxide film affects the wetting speed of wave soldering

After domestic solder bars are exposed to air for 4 hours, the surface oxide film thickness can reach 180nm, leading to a wave soldering wetting time extended to over 3.2 seconds. JJY adopts nitrogen sealing + aluminum foil double-layer packaging. Before shipment, each batch is sampled for inspection with an oxide film thickness ≤65nm. Combined with the optimized Sn96.5/Ag3.0/Cu0.5 alloy ratio, the copper plate wetting time is stabilized at around 1.9 seconds, and the IMC layer thickness fluctuation range is compressed to 1.8～2.3μm.

All materials are mandatorily sieved and re-inspected for particle size before leaving the factory

Each batch of solder paste must be dynamically sieved twice through a 300-mesh stainless steel screen before filling, and the D10/D50/D90 distribution is re-measured with a laser particle size analyzer. The solder wire needs to be scanned over the entire coil with an eddy current flaw detector with 0.01mm accuracy. The surface roughness Ra value of the solder bar is sampled on-site with a portable profilometer. The data is uploaded to the MES system in real time for traceability. The purchaser can scan the code to retrieve the original inspection curve and the operator's employee ID.