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.

Citation

Seo, W. and Kim, J. (2013), "Filling analyses of solder paste in the stencil printing process and its application to process design", Soldering & Surface Mount Technology, Vol. 25 No. 3, pp. 145-154. https://doi.org/10.1108/SSMT-Oct-2012-0022