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Here you can find knowledge about Printing Solder Paste, including but not limited to usage methods, installation techniques, troubleshooting and more. Focused on SMT soldering processes. If you can't find what you need, please contact us anytime.
Aiming at the common edge collapse problem in solder paste printing for thick boards, this paper starts with the collaborative optimization of solder paste rheological properties, stencil aperture design and squeegee parameters, proposes a solder paste selection standard for thick boards adapted to PCB thicknesses above 0.8mm and a tightening scheme for the solder paste printing process window, and emphasizes that yield improvement can be achieved through solder paste viscosity gradient matching and fine-tuning of the standing time before reflow without replacing equipment.
Published: 2018-11-19Post-printing solder paste placement failure and downtime stencil cleaning time directly determine the SMT first-pass yield. If solder paste remains on the stencil for more than 15 minutes, obvious slump, oxidation, and viscosity increase will occur. If stencil cleaning is delayed for more than 30 minutes after downtime, dried residual solder paste will cause solder spikes and insufficient solder in the next batch of printing. The production line must dynamically set the effective window after solder paste printing and the stencil cleaning response threshold based on solder paste type, workshop temperature and humidity, and printing frequency.
Published: 2018-10-03The sphericity, particle size distribution, and oxidation level of tin powder particles in SAC solder paste directly affect the release integrity and pad coverage during solder paste printing. Actual production lines have found that spherical tin powder with a D50 of 25μm can achieve a release rate of over 92% on a 38μm aperture stencil. When the D50 deviation exceeds ±1.5μm or the oxygen content is >0.5wt%, the defect rates of solder bridging and insufficient solder increase by more than 3 times. The process compatibility of solder paste, SAC solder paste, and tin powder solder paste must be based on measured particle parameters.
Published: 2018-04-13In the entire chip soldering process, the precision of solder paste printing via SMT stencil directly determines the yield of subsequent component placement and reflow soldering. The viscosity, particle size, and metal content of the solder paste, as well as printing parameters such as squeegee pressure, speed, and release distance, must be coordinated and matched with the actual conditions of the production line. Any mismatch will cause typical defects such as insufficient solder, solder bridging, and misalignment.
Published: 2017-09-07SMT 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.
Published: 2017-04-18To 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.
Published: 2016-11-09
Poor sphericity of solder powder in solder paste significantly reduces print forming rate, leading to high-frequency defects such as missing printing, solder bridging, and misalignment, which is particularly prominent on 0201 and smaller package devices. Non-spherical solder powder has poor fluidity, high rolling resistance, and increased friction with the stencil aperture walls, directly affecting solder paste release rate and demolding consistency.
Published: 2016-05-12In SMT printing, the rheological properties of solder paste directly affect continuous printing stability. An excessively high thixotropic index easily leads to poor demolding and edge pinholes, while an excessively low thixotropic index causes slump and aperture clogging. Jiajinyuan solder paste achieves precise control of the viscoelasticity ratio. Under 25°C environment and 0.5mm stencil conditions, the measured thixotropic index is 1.8～2.3. Combined with the parameter set of squeegee pressure 2.8kg and speed 45mm/s, it can continuously complete 1200 PCBs without aperture clogging.
Published: 2016-04-10
The design of solder paste stencil aperture openings directly affects the release performance of stencil printing and the forming quality of solder paste. Undersized apertures lead to insufficient solder paste volume and edge tearing, while oversized apertures easily cause bridging and slumping. Moreover, the aperture shape, wall roughness, and taper design alter the contact area and separation stress between the solder paste and the stencil. These factors are often overlooked in actual production lines, yet they directly determine the first-pass yield and SPI yield.
Published: 2014-12-18The pressure adjustment of the squeegee for solder paste printing directly affects the solder paste forming quality. Excessive pressure will cause solder paste collapse, solder spikes or leakage under the stencil, while insufficient pressure will lead to insufficient solder volume, jagged edges or local missing printing. Combined with the rheological properties of printing solder paste and solder paste parameters such as viscosity, metal content and thixotropic index, on-site fine-tuning within the range of 50～120N is required, while simultaneously observing the stencil rebound status, squeegee trailing marks and pad filling completeness.
Published: 2014-10-12Our technical team is always ready to provide professional solder material selection advice and SMT process solutions.