ABSTRACT

Currently, adhesive bonding processes are developed and optimised in a time-consuming trial and error procedure, which rarely leads to an optimal solution due to the high complexity of the adhesive flow behaviour during application. The ideal adhesive layer has precise geometric specifications; entrapped air bubbles or overfilling of the bond should be avoided. Numerical methods, such as Computational Fluid Dynamics (CFD), are only capable of calculating squeeze-flow processes to a limited extent. Apart from high computing times, mesh and convergence problems often occur due to the small ratio of adhesive layer thickness to adhesive layer length and width. The Generalised Partially Filled Gap (GPFG) model, published in a companion paper uses fundamental characteristics of every bonding process to derive clever assumptions, and thus provide an efficient simulation tool for adhesive squeeze-flow. The GPFG model simplifies the squeeze-flow to a two-dimensional problem, as the flow in thickness direction can be neglected for most bonding processes – without significant loss of accuracy compared to analytical or CFD solutions. The experimental validation of the model is presented in this study. Both stresses and flow geometry were evaluated, and a very good agreement between experiments and model was proven.

摘要

目前，粘合剂粘合工艺是在一个耗时的试错过程中开发和优化的，由于应用过程中粘合剂流动行为的高度复杂性，这很少导致最佳解决方案。理想的胶层具有精确的几何规格；应避免夹带气泡或过度填充粘合剂。数值方法，例如计算流体动力学 (CFD)，只能在有限的范围内计算挤压流过程。除了高计算时间之外，由于粘合层厚度与粘合层长度和宽度的比例较小，经常会出现网格和收敛问题。发表在配套论文中的广义部分填充间隙 (GPFG) 模型使用每个键合过程的基本特征来得出巧妙的假设，从而为粘合剂挤压流动提供了一种有效的模拟工具。GPFG 模型将挤压流动简化为二维问题，因为对于大多数键合工艺来说，厚度方向的流动可以忽略不计——与解析或 CFD 解决方案相比，精度没有明显损失。本研究介绍了该模型的实验验证。对应力和流动几何进行了评估，并证明了实验和模型之间的非常好的一致性。