聚合物超声波封接过程中超声传播的数值模拟

Numerical simulation on ultrasound propagation duringultrasonic bonding process of polymer

在聚合物超声波封接中超声波的传播效率能够实时反映聚合物材料的力学状态变化,使其能够成为封接中的参考变量.针对该参量对超声波封接过程中的超声波传播进行了有限元仿真,依据超声波封接过程建立包含工具头、微器件和底座等有限元模型.根据聚合物材料的黏弹性本构关系,模拟了不同温度和振幅下的超声波封接.通过计算模型中每组接触面间的接触力,研究界面间接触力与温度、振幅的关系,从而分析超声波在聚合物内的传播规律.结果表明:聚合物微器件熔接区内与温度、能量相关的力学性能模量对超声波在聚合物内的传播具有重大影响,超声波的传播效率随着微器件温度的升高而衰减,随着超声波振幅的增大而增加.

Owing that the ultrasound propagation can reflect the property variation of polymer during the ultrasonic bonding process, the ultrasound propagation, a critical parameter for ultrasonic bonding, is further studied via finite element method. By establishing the ultrasonic bonding model with horn, polymer components and anvil, the ultrasonic bonding simulation processes under different temperatures and amplitudes are conducted on the constitutive relationship between polymer viscoelasticities. Subsequently, the relationships among contact force and temperature, amplitude are obtained based on interracial contact forces. Consequently, the regulation of ultrasound propagation in the polymer is analyzed. Therein, it is detected from results that the ultrasonic propagation in the polymer is significantly affected by the mechanical properties of fusion layer with regard to temperature and energy, whereas the ultrasound propagates and attenuates with rising temperature and increasing amplitude.