Effects of Different Viscometer Test on Stencil Printing Process for CFD Simulation

Abstract This study discusses the use of different spindle type for the testing of lead-free solder paste by using Computational Fluid Dynamics (CFD) simulation. The study focuses on measuring the volume of solder paste deposition on the solder pad. Parallel-plate (PP) and Cone-plate (CP) spindle were used with five different tests consist of different spindle type and setting. The Volume of Fluid (VOF) method was used for the simulation while Cross model was applied as viscosity model for the solder paste. SAC305 type 3 lead-free solder paste was used in this study as it is mostly popular used by the industries nowadays. The solder paste filled the volume under different squeegee speeds and aperture size was compared between experiments and simulations. For different squeegee speed, PP 0.5 mm gap obtained the lowest average discrepancy value between simulation and experimental results. At different aperture size, all test show similar trend line and about the same value of average discrepancy with CP1° while PP 0.5 mm gap showed the lowest average discrepancy. At small aperture volume, all tests performed shows similar value of filled volume except PP 0.5 mm which exhibit the lowest percentage difference when compared with the experimental values at a bigger aperture volume.