THE PERFORMANCE OF VIBRATING SQUEEGEE IN THE STENCIL PRINTING OF SOLDER PASTES

Abstract

The vibrating squeegee is considered by many to be one of the important developments in solder paste printing in recent years. The use of the vibrating squeegee for stencil printing of solder paste used for reflow soldering of surface-mount devices can provide several benefits. In this paper, the performance of vibrating squeegee for stencil printing of solder paste is analysed. It is shown that the vibrating squeegee could aid in the close packing of solder alloy particles, and also provide better solder paste roll in front of the squeegee. It is also shown that the vibration will produce a liquid-rich layer between the leading edge of the squeegee and the paste roll, thereby reducing the squeegee’s resistance to the paste roll. The behavior of the solder paste beneath the vibrating squeegee is analysed using oscillatory shear theory and data from oscillatory shear experiments on other dense suspensions. The effect of kinematic parameters such as printing speed, vibration amplitude and frequency are also discussed.