In-situ analysis of microstructure development and powder aging during powder bed fusion of plastics using dielectric relaxation spectroscopy

使用介电弛豫光谱对塑料粉末床熔融过程中的微观结构发展和粉末老化进行原位分析

• 批准号: 504676034
• 负责人: Professorin Dr.-Ing. Katrin Wudy
• 金额: --
• 依托单位: Professur für Laser-basierte Additive Fertigung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/504676034?language=en
• 关键词: situ; analysis; microstructure; development; powder

One of the greatest challenges in the powder bed fusion of plastics using laser-beam (PBF-LB/P) is the analysis of the microstructure development within the process. According to the state-of-the-art and current research, the in-situ analysis of the material behavior is primarily based on thermographic or imaging processes in PBF-LB/P. These methods do not allow any conclusions on microstructure development such as crystallization and aging mechanism of the polymer during the process. This challenge is addressed by the project “In-situ analysis of microstructure development and powder aging during powder bed fusion of plastics using dielectric relaxation spectroscopy”. The objective of the project is to fundamentally understand the melting and crystallization dynamics in PBF-LB/P during processing by using in-situ dielectric relaxation spectroscopy (DRS). DRS has proven to be a powerful tool for investigating phase transition areas, crystallization kinetics, moisture content, and physical and chemical aging mechanisms. This analyzing method is based on an electrical sinusoidal excitation of a polymer sample and provides detailed information on relaxation and translation phenomena. In addition, DRS is a robust and fast measurement method that has already proven its potential for in-situ monitoring in polymer processing. The latest developments in DRS sensors enable the contact-free analysis of polymer samples. This qualifies DRS as a perfect tool for implementation in the PBF-LB/P process in order to gain a deeper understanding of the microstructure formation and powder aging during processing even across several layers. Within the scope of the project, a correlation between process parameters, material-dependent process behavior, and resulting component properties is to be derived on the basis of in-situ DRS measurements. In addition to the melting and crystallization behavior, process-inherent properties of the so-called partcake powder, such as aging effects or the moisture content, will be explored to recommend further powder treatment, such as recycling of the powder, following the process without any additional measurement. In order to generate a generally valid understanding of the process, the investigations are first carried out on the well-understood material PA12, and then the findings are transferred to filled PA12 and TPU. This project represents a unique combination of materials science and additive manufacturing and answers fundamental and unresolved questions of microstructure development in PBF-LB/P.

激光熔融塑料粉末床(PBF-LB/P)的最大挑战之一是分析该过程中的微观结构发展。根据目前的研究现状，材料行为的原位分析主要基于PBF-LB/P的热像或成像过程，这些方法不允许对过程中聚合物的结晶和老化机理等微观结构的发展做出任何结论。“利用介电弛豫谱对塑料粉末床熔融过程中的微结构发展和粉末老化进行现场分析”项目解决了这一挑战。本项目的目标是利用原位介电弛豫谱(DRS)从根本上了解PBF-LB/P在加工过程中的熔融和结晶动力学。DRS已被证明是研究相变区、结晶动力学、水分含量以及物理化学老化机理的有力工具。这种分析方法是基于聚合物样品的正弦电激励，提供了关于松弛和平移现象的详细信息。此外，DRS是一种稳健而快速的测量方法，已证明其在聚合物加工中的现场监测潜力。DRS传感器的最新发展使聚合物样品的非接触分析成为可能。这使DRS成为在PBF-LB/P工艺中实施的完美工具，以便更深入地了解加工过程中的微结构形成和粉末老化，甚至跨越几个层。在项目范围内，将根据现场DRS测量得出工艺参数、依赖于材料的工艺行为和所产生的部件性能之间的关联。除了熔化和结晶行为外，还将研究所谓的部分蛋糕粉末的工艺固有特性，如老化效应或水分含量，以建议在不进行任何额外测量的情况下进行进一步的粉末处理，如回收粉末。为了对该过程有一个普遍有效的理解，首先对人们熟知的材料PA12进行调查，然后将调查结果转移到填充的PA12和TPU上。该项目代表了材料科学和添加剂制造的独特结合，并回答了PBF-LB/P微观结构开发的基本和悬而未决的问题。