Microcellular injection molding (MIM) is a fast-growing technology with high potential to become an innovative and green manufacturing platform for fabrication of porous, polymer-based products. In this review article, the process know-how of MIM in terms of blowing agent and cell structures is discussed first. Then, some emerging and complementary processing technologies that incorporate MIM are introduced. The technologies presented here include core-back foaming, supercritical fluid-laden pellet injection molding foaming technology (SIFT), subcritical gas assisted processing (SGAP), and the in-situ fibrillation process. By employing a special mold design and novel processing steps, gas-laden pellet extrusion, alternate and cost-effective gas sources, and/or in-situ fibrillation, these technologies aim to improve the performances and quality of the resulting foamed parts. Finally, the current challenges along with future directions of MIM, such as surface quality improvement, nano-cellular structures, and accurate simulations, are presented.

微孔注射成型 (MIM) 是一种快速发展的技术，具有成为制造多孔聚合物产品的创新和绿色制造平台的巨大潜力。在这篇评论文章中，首先讨论了 MIM 在发泡剂和泡孔结构方面的工艺诀窍。然后，介绍了一些包含 MIM 的新兴和补充处理技术。这里介绍的技术包括芯背发泡、超临界流体负载颗粒注射成型发泡技术 (SIFT)、亚临界气体辅助加工 (SGAP) 和原位纤维化工艺。通过采用特殊的模具设计和新颖的加工步骤、充气颗粒挤出、替代且具有成本效益的气源和/或原位原纤化，这些技术旨在提高所得泡沫部件的性能和质量。最后，介绍了当前的挑战以及 MIM 的未来方向，例如表面质量改进、纳米细胞结构和精确模拟。