Experimental investigation, modeling, and simulation of mold filling and cell structure development in foam injection molding

泡沫注射成型（FIM）是塑料泡沫加工中最通用的技术之一，它能够在快速的生产周期内生产出具有复杂三维几何形状的轻质零件。其应用范围从包装和建筑到汽车和航空航天工业。但在此过程中，泡沫结构的控制是一个难点。大多数制造商依靠艰苦的试错或类似的技术来制造具有预定特性或功能的泡沫。作为一种解决方案，许多公司已经开发了设计和分析软件。然而，这些软件被设计用于模拟模具填充、焊缝定位、翘曲分析和非发泡固体部件的温度分布。目前，最先进的商业软件只能提供不充分的结果来预测发泡行为。为了加快泡沫产品的设计，并以经济有效的方式控制泡沫形态，需要一个精确的泡沫模块。在这方面，我们正在与领先的工程软件公司Autodesk Moldflow合作，以改进其现有的发泡软件模块并开发可靠的FIM仿真软件。目前Autodesk Moldflow提供的仿真模块使用的是一种拟合方法，这种方法是不准确的，并且仅限于某些简单的低压试验。在这种情况下，Autodesk Moldflow寻求我们的帮助来改进他们的泡沫模块。这将通过我们的新合作和应用我们的可视化模具来完成，它可以准确地可视化发泡现象。总体思路如下：(1)可视化半结晶聚合物材料及其复合材料发泡过程中的复杂现象；（ii）为观察到的机制推导数学公式并实施模型；（iii）开发最终泡沫形态预测的大规模模拟算法。与目前的NSERC CRDPJ 492659-15项目一起，从这个新的CRD项目中获得的知识将使我们的合作伙伴能够开发出更准确、更可靠的发泡模块，最终使加拿大泡沫工业在全球市场上处于更具竞争力的地位。

Foam injection molding (FIM), as one of the most versatile technology in plastic foam processing, is capable of producing light-weight parts with complex three-dimensional geometries in a fast production cycle. Its applications range from packing and construction to automotive and aerospace industries. However, controlling the foam structure is difficult in this process. Most manufacturers rely on painstaking trial-and-error or similar techniques to fabricate foams with predetermined properties or functionalities. As a solution, design and analysis software has been developed by a number of companies. However, these softwares were designed for simulating mold-filling, weld-line location, warpage analysis, and temperature distribution for unfoamed solid parts. Currently, the state-of-the-art commercial software offers only inadequate results for prediction of foaming behavior in FIM. To expedite foam product design and to control foam morphology in a cost-effective way, a precise foam module is needed. In this regard, we are collaborating with the leading engineering software company, Autodesk Moldflow, to improve its existing foaming software module and develop reliable FIM simulation software. The current simulation module provided by Autodesk Moldflow uses a fitting method, which is inaccurate and limited to certain simple low-pressure trials. In this context, Autodesk Moldflow sought our help in improving their foam module. This will be accomplished through our new collaboration and by applying our visualization mold, which can accurately visualize the foaming phenomena. The overall approach is as follows: (i) visualization of the complex phenomena during foaming of semicrystalline polymer materials and their composites; (ii) derivation of mathematical formulations for the observed mechanisms and implementation of models; (iii) development of large-scale simulation algorithm for final foam morphology prediction. Together with the current NSERC CRDPJ 492659-15 project, the gained knowledge from this new CRD project will allow our partner to develop more accurate and reliable foaming module, and eventually allow the Canadian foam industries to be at a more competitive position in the global market.