摘要
芯片表面贴装过程中需要通过点胶工艺将微量胶液定量配发到基板上的指定位置,该过程对胶液配发量的一致性有很高的要求。针对现有对接触式微量点胶过程研究中普遍将胶液挤出量视为实际转移量的问题,通过对针头处胶液与基板接触拉断过程动力学行为分析,建立多参数下胶液转移过程动力学模型;并建立胶滴在基板上稳态后的形状理论模型,用以验证体积函数模型(Volume of fluid,VOF)对气液两相流界面追踪的有效性。在此基础上,结合VOF模型、Brackbill表面张力模型及动网格法对胶液接触拉断过程动态行为进行数值模拟,获得了不同接触距离、胶液拉断速度、胶液与基板间的接触角对胶液转移量的影响规律。结果表明,胶液拉断后针头上会有少量胶液残留,即胶液实际转移量总小于挤出量,且在给定压力下,转移量随接触距离、拉断速度和接触角的不同而变化。研究结果可为接触式微量点胶过程定量控制提供理论参考。
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.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2014年第14期197-203,共7页
Journal of Mechanical Engineering
基金
国家自然科学基金资助项目(51005134)
关键词
接触式点胶
拉断过程
数值模拟
转移量
挤出量
contact dispensing
stretch process
numerical simulation
transferred amount
extruded amount
