关键词: 接触式点胶;拉断过程;数值模拟;残留量;转移量

Abstract: Dispensing technology has been used to dispense the micro-epoxy in the appointed place of substrate in surface mount technology(SMT), which requires high consistence of the amount of dispensing epoxy droplets. The extruded epoxy is generally regarded as the transferred amount in current research on the contact dispensing process. By analyzing the dynamics process of epoxy transferring from needle tip to substrate, this research establishes the dynamics model of epoxy transferring process with multi-parameters. Meanwhile, the theoretical model of drop shape is established when epoxy is transferred to substrate and reaches steady state, aiming at verifying the effectiveness of volume of fluid(VOF) on the interface reconstruction of gas-liquid flow. On this foundation, the dynamic process of epoxy breaking is simulated numerically by combining the gas-liquid flow volume function model, Brackbill surface tension model and moving grid method to verify the epoxy transfer process for different contact distance, stretching speed and contact angle. The results show that the actual transferred amount of epoxy is always less than extruded amount owing to little residue on the pinhead, and transfer rate fluctuates with contact distance, stretching speed and contact angle at a given pressure, which provide a theoretical reference for quantitative control of contact dispensing.

Key words: contact dispensing;stretch process;numerical simulation;transferred amount;extruded amount