High-viscosity solder paste significantly improves the placement offset issues of 0201, 0402 and other tiny components as well as irregular devices in SMT production, and is especially suitable for complex scenarios such as double-sided reflow, stepped stencils, and high-density board layouts. Its characteristics of strong thixotropy, low slump rate, and long room-temperature holding time reduce the component displacement rate during the solder paste placement process by more than 40%, while easing the pressure on the waiting window from after printing to before placement.

SMT stencils are core consumables in the SMT solder paste printing process. Their aperture size, thickness, surface treatment, and tension state jointly determine the stability of solder paste transfer volume. Jiajinyuan SMT stencils, through laser cutting precision control and electropolishing process optimization, achieve a solder paste transfer rate of over 92% at a thickness of 0.12mm, effectively suppressing common high-frequency production line defects such as insufficient solder, solder bridging, and edge burrs.

The solder used in energy storage modules is extremely sensitive to voiding rate. Low-void solder paste can control the voiding rate of BGA solder joints within 5%, significantly improving the thermal fatigue life of electronic control boards under high-power cycling. Jiajinyuan JY-810A solder paste, with its stable thixotropy, low residue, and reflow wetting angle of less than 25°, has become a practical combination for BGA soldering of electronic control boards in the selection of solder materials for energy storage modules.

SMT placement pressure control directly affects the deformation state of solder paste. Excessive pressure will cause the solder paste to be squeezed laterally to both sides of the pad, leading to bridging defects. JIAJINYUAN placement machines achieve ±0.02N precision control through real-time pressure feedback and Z-axis dynamic compensation, combined with stencil aperture design matched with the rheological properties of solder paste, to suppress bridging from the source.

The solder joint cracking rate of FPC soldered flexible screen modules under repeated bending scenarios is significantly reduced. The key lies in optimizing the solder paste printing accuracy, matching the reflow soldering temperature profile to the thermal expansion characteristics of the FPC substrate, and strictly controlling the FPC mounting offset and Z-axis pressure. Jiajinyuan's actual measurement shows that the cracking rate after 200,000 bending cycles is less than 0.3%, which is far better than the industry's conventional level of 0.8%.

Improper sealing of refrigerated solder paste will accelerate solder paste oxidation, leading to poor printing release, increased solder joint void rate, and insufficient wetting after reflow. Especially in high-temperature and high-humidity seasons, the surface of unsealed refrigerated solder paste is prone to forming a gray-black oxide film, which directly affects the first pass yield of the SMT production line. Therefore, standardizing the sealing management of refrigerated solder paste is a key link in controlling solder paste oxidation.

Cold solder joints are almost impossible to identify visually with the naked eye or via conventional AOI, and must be exposed through power-on testing and thermal stress excitation. Their essence is the absence of continuous metallurgical bonding between the solder joint metals, leading to signal transmission interruption, abnormal temperature rise, and intermittent failures. Statistics from the JJY production line show that 73% of customer returns caused by cold solder joints occur after 48 hours of complete machine aging.

Jiajinyuan PCBA soldering materials are specifically designed for new energy battery management system BMS boards, photovoltaic inverter control boards, and industrial PLC main control boards. Its low-void-rate solder paste maintains a stable void area of less than 12% after reflow in 0.3mm fine-pitch QFN packages, which can be further reduced to 8.5% with a nitrogen atmosphere, meeting the stringent requirements of automotive-grade AEC-Q200 for solder joint reliability.

High-frequency PCB soldering is extremely sensitive to the halogen content and residue control of solder paste. Jiajinyuan halogen-free low-residue solder paste, by optimizing the rosin system and activator ratio, ensures wettability while reducing ionic contamination to below 0.25μg/cm2, significantly minimizing impedance fluctuations and phase shifts in high-frequency signal transmission.

Humidity control in the immersion silver board welding workshop is a key process measure to suppress silver layer migration. When the ambient relative humidity is higher than 60%RH for a long time, an electrolyte film is easily formed on the surface of the immersion silver board, which accelerates the electrochemical migration of silver ions between the pad and the edge of the solder mask. Actual measurements on the Jia Jinyuan production line show that stably controlling the humidity within the range of 40% to 55%RH can reduce the silver migration failure rate by 72%. Combined with nitrogen-protected reflow soldering and matching the activity level of the solder paste, it can significantly improve the long-term reliability of immersion silver board welding.

To address the unstable yield of 0.4mm and below fine-pitch solder paste printing, this paper, based on 20 years of measured data from the Jiajinyuan production line, clarifies that the stencil aperture ratio needs to be dynamically adjusted within the range of 75% to 85%. Among them, 82% is recommended for QFN0.4mm, and it must be reduced to 76% for BGA0.3mm. It is also pointed out that an aperture ratio deviation exceeding ±3% will cause solder bridging or insufficient solder. The core lies in balancing the solder paste release rate and the stencil demolding capability.

For the export of 5G equipment solder, a full set of inspection documents compliant with IEC 61190-1-1, JIS Z 3284 and RoHS 2.0 requirements must be provided simultaneously, covering solder composition reports, melting point curves, wettability tests, halogen content, intermetallic compound thickness and tin whisker growth assessment. All export batches of Jia Jinyuan are subject to full-item third-party testing by SGS or CTI in accordance with customer-specified standards, with original data attached.

When manually soldering wiring harness terminals, using large-size solder wire of 1.6mm or above with a soldering iron temperature of 350℃±10℃ can achieve full-formed solder joints at one time without cold soldering, sharp tips or dry joints, significantly improving the electrical connection reliability of the wiring harness under vibration conditions. This process has been batch verified on multiple new energy vehicle high-voltage wiring harness production lines of JJY.

To address the frequent occurrence of batch SMT defects, this paper proposes a practical method based on coordinated troubleshooting across three key stages: solder paste printing, placement offset, and reflow profile. By leveraging rapid microscopic comparison, first-article parameter traceability, and cross-validation of measured reflow temperature data, the root cause can be identified within 30 minutes, significantly reducing production line downtime and effectively controlling the spread risk of SMT defects.

Continuous oxidation on the surface of molten solder during wave soldering is the main cause of solder dross formation. High temperatures, air exposure, flux residues, and agitation of the solder bath collectively accelerate the rupture and agglomeration of the oxide film, leading to increased solder dross volume, higher solder consumption, and more frequent equipment maintenance. Field measurements on Jia Jinyuan production lines show that when the increase in solder dross per shift exceeds 1.2kg, solder costs rise by 8.6% year-on-year. Timely oxygen control and solder surface cleaning can reduce solder dross generation by more than 35%.

Nitrogen reflow is a key method for improving soldering reliability in high-end SMT processes, but higher nitrogen concentration is not always better. Actual measurements on Jia Jinyuan's production lines show that within the 99.5% to 99.9% range, every 0.1 percentage point increase raises nitrogen consumption costs by 8%, while the improvement in solder joint void rate slows down. The target value must be dynamically set based on PCB thickness, BGA solder ball size, and solder paste activity grade.

Adjusting solder paste process parameters under a nitrogen reflow environment can significantly reduce the solder paste void rate. It is necessary to simultaneously optimize the heating slope, peak temperature and atmospheric oxygen content of reflow soldering, and combine stencil aperture design with squeegee pressure to control printing accuracy, so as to avoid cold solder joints and poor wetting caused by uneven nitrogen displacement or hindered flux volatilization.

High tensile strength of connector solder joints directly improves the reliability of the whole machine. Jiajinyuan connector solder, by optimizing the ratio of tin-silver-copper and active flux components, achieves an average tensile strength ≥8.2N at a conventional reflow peak temperature of 235℃, with no solder joint detachment, no cold solder joint, and no solder joint cracks after 100 insertion and removal cycles. It is especially suitable for industrial control and automotive electronics production lines under high-frequency vibration conditions.

AOI inspection after SMT reflow soldering can efficiently identify appearance soldering defects such as solder joint bridging, tombstoning, solder beads, and misalignment, greatly reducing the missed inspection rate of manual visual inspection. With a pixel accuracy of 0.015mm and the capability of multi-angle light source switching, Jia Jinyuan's AOI inspection equipment stably controls the false alarm rate within 1.2% for solder joint judgment of components below 0603.

To address the issue of solder joint cracking caused by concentrated thermal stress in energy storage new energy electronic control boards during frequent charge-discharge cycles, solder paste with high ductility, low elastic modulus, and excellent thermal cycle life must be selected. New energy solder paste must pass thermal shock verification at -40℃ to 125℃ for more than 1000 cycles, while reliability solder paste emphasizes the uniformity of the IMC layer and the stability of the Cu6Sn5 phase. The metal content, particle size distribution, and flux residue ion concentration of the solder paste jointly determine its long-term thermal fatigue resistance.