Filling analyses of solder paste in the stencil printing process and its application to process design

Abstract

Purpose -The purpose of this paper is to suggest an analysis methodology for the stencil printing process and to obtain proper design parameters that guarantee the successful filling using suggested finite element analyses. Design/methodology/approach -Filling performance of solder paste in the stencil printing process is highly dependent on material properties such as viscosity and surface tension together with process parameters such as squeegee angle and squeegee speed. In order to investigate the effects of process parameters on the filling performance, the pressure built-up under the squeegee and the filling procedure of the solder paste into an aperture were analysed. Due to the limitations of the computational memory and time, the analysis domain was simplified. The pressure development under the squeegee was investigated for various values of squeegee angle and speed; then, the filling behaviour with the pressure boundary condition was analysed for only one aperture. Finally, the two analysis results were integrated to obtain the successful filling condition. In this analysis method, process parameters that guarantee filling performance were decided on. Findings -It was shown that higher squeezing pressure develops as the squeegee angle decreases and the squeegee speed increases. The filling performance, however, improves as the squeegee angle and the squeegee speed decrease. This is because the pressure duration time decreases as the squeegee speed increases. Originality/value -This study suggests a new design approach to obtain proper process design parameters for successful filling of solder paste into an aperture. The direct analysis of filling with squeegee movement is impossible due to limitations of computer memory and computation time. To overcome these limitations, a two steps analysis approach is proposed and can be effectively applied in the design of stencil screen printing.

Finite volume modelling of stencil printing process

“…al. investigated the aperture filling during stencil printing [12]. Unfortunately, they applied Newtonian properties for the solder paste; so their results are questionable.…”

Strata Movement of the Thick Loose Layer under Strip-Filling Mining Method: A Case Study

“…Some researchers have established a mechanical model of the thin bedrock face structure, and they pointed out that a thick clay layer with greater bearing capacity can be combined with a thin bedrock to form a stable structure [28][29][30][31]. Some scholars regarded the thick loose layer and single thin bedrock as the load-bearing structure acting on the solid filling material, and they established a single-layer thin bedrock elastic continuous beam model [32][33][34][35]. The above-mentioned research has enriched the theory and practice of overlying rock movement and deformation in mining under thick loose layers [36][37][38].…”

Transient Numerical Modelling of the Pin-in-Paste Technology

“…Seo and Kim introduced an analysis method of solder paste flow into the stencil apertures [13]. Their method included a double-step 3D modelling approach due to the limitation in computational resources.…”

“…Figure13. Comparing the hole-filling of rectangular-shaped holes (1 × 2 mm) oriented in parallel with or perpendicular to the travelling direction of the printing squeegee (printing speed was 120 mm/s).…”