Momeni Vahid, Hufnagl Margarete, Shahroodi Zahra, Gonzalez-Gutierrez Joamin, Schuschnigg Stephan, Kukla Christian, Holzer Clemens
Polymer Processing, Montanuniversitaet Leoben, 8700 Leoben, Austria.
Functional Polymers Research Unit, Materials Research and Technology (MRT) Department, Luxembourg Institute of Science and Technology (LIST), L-4940 Luxembourg, Luxembourg.
Materials (Basel). 2022 Dec 30;16(1):379. doi: 10.3390/ma16010379.
Powder injection molding (PIM) is a well-known technique to manufacture net-shaped, complicated, macro or micro parts employing a wide range of materials and alloys. Depending on the pressure applied to inject the feedstock, this process can be separated into low-pressure (LPIM) and high-pressure (HPIM) injection molding. Although the LPIM and HPIM processes are theoretically similar, all steps have substantial differences, particularly feedstock preparation, injection, and debinding. After decades of focusing on HPIM, low-viscosity feedstocks with improved flowability have recently been produced utilizing low-molecular-weight polymers for LPIM. It has been proven that LPIM can be used for making parts in low quantities or mass production. Compared to HPIM, which could only be used for the mass production of metallic and ceramic components, LPIM can give an outstanding opportunity to cover applications in low or large batch production rates. Due to the use of low-cost equipment, LPIM also provides several economic benefits. However, establishing an optimal binder system for all powders that should be injected at extremely low pressures (below 1 MPa) is challenging. Therefore, various defects may occur throughout the mixing, injection, debinding, and sintering stages. Since all steps in the process are interrelated, it is important to have a general picture of the whole process which needs a scientific overview. This paper reviews the potential of LPIM and the characteristics of all steps. A complete academic and research background survey on the applications, challenges, and prospects has been indicated. It can be concluded that although many challenges of LPIM have been solved, it could be a proper solution to use this process and materials in developing new applications for technologies such as additive manufacturing and processing of sensitive alloys.
粉末注射成型（PIM）是一种众所周知的制造技术，可用于制造形状复杂的网状宏观或微观零件，所使用的材料和合金种类繁多。根据注射原料时所施加的压力，该工艺可分为低压（LPIM）和高压（HPIM）注射成型。尽管LPIM和HPIM工艺在理论上相似，但所有步骤都存在实质性差异，特别是在原料制备、注射和脱脂方面。在专注于HPIM几十年之后，最近利用低分子量聚合物生产出了具有更好流动性的低粘度原料用于LPIM。事实证明，LPIM可用于小批量或大规模生产零件。与只能用于金属和陶瓷部件大规模生产的HPIM相比，LPIM为涵盖低批量或大批量生产率的应用提供了绝佳机会。由于使用了低成本设备，LPIM还具有若干经济效益。然而，为所有需在极低压力（低于1MPa）下注射的粉末建立最佳粘结剂体系具有挑战性。因此，在混合、注射、脱脂和烧结阶段可能会出现各种缺陷。由于该工艺的所有步骤都是相互关联的，因此全面了解整个工艺过程很重要，这需要科学的概述。本文综述了LPIM的潜力以及所有步骤的特点。已指出了关于应用、挑战和前景的完整学术和研究背景调查。可以得出结论，尽管LPIM的许多挑战已得到解决，但在为增材制造和敏感合金加工等技术开发新应用时，使用该工艺和材料可能是一个合适的解决方案。
