超声波线焊的两维非接触有限元分析

在超声波线焊中,虽然金线和焊接平台间的接触界面较大,但实验显示,焊接部位只发生在接触截面的周边,这是一种特别的焊接界面形态和超声波线焊的机理。本文采用弹塑性、大变形的非线性有限元方法,模拟了超声波线焊的过程,分析了接触界面的接触压强分布,发现不均匀的接触压强分布是导致这种焊点形态的主要原因。这种不均匀的焊点形态也将影响对压碶按压力作用的理解,过高的压碶按压力并不一定有助于超声波线焊。

Two-dimensional Contact Finite Element Analysis of Ultrasonic Wire Bonding

A main character in ultrasonic wire bonding is the welding formation in the contact area. The character shows that the welding area locates only at the periphery of the contact area, although the contact area between the wire and pad is much larger. A finite element analysis considering the non-linearity in geometry and material properties is adopted to simulate the process of ultrasonic wire bonding. An uneven contact pressure between the wire and pad is indicated, which explains the welding formation in experiments. The function of the bond force is discussed and higher bond force does not mean higher bondability.