Numerical Study on the Effect of Different Viscometer Test on Stencil Printing Process

Abstract

Using CFD simulation, this study analyses the applicability of several spindle types for assessing lead-free solder paste. The purpose of this investigation is to determine how much solder paste applied on the solder pad. Five separate studies were conducted on parallel-plate (PP) and cone-plate (CP) spindles. The simulation was performed by using the Volume of Fluid (VOF) approach, and the Cross model represented solder paste viscosity. Since it is popularly used in modern industry, lead-free solder paste SAC305 type 3 was chosen for this study. Regardless of squeegee speed or aperture size, solder paste always filled the volume. The PP with 0.5 mm gap exhibits the smallest average disparity between simulation and experiment for all squeegee speeds tested. For 1⁰ CP, all experiments show similar trend line with average disparity except for 0.5 mm PP. All tests with very small aperture volumes produced comparable filled volume values, except for 0.5 mm PP test, which showed the smallest percentage change when the experimental data is compared at higher aperture volumes. This method can be used by other simulation researchers to get solder paste’s viscosity data for their solder paste simulation.