Numerical and experimental investigations of dimensionless material parameters in laser additive manufacturing of polymers for accelerated material development and process optimization – Phase 2: Expansion of the application field optimization

聚合物激光增材制造中无量纲材料参数的数值和实验研究，以加速材料开发和工艺优化 â 第 2 阶段：应用领域优化的扩展

• 批准号: 409621284
• 负责人: Dr. Claas Bierwisch
• 金额: --
• 依托单位: Fraunhofer-Institut für Werkstoffmechanik (IWM)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/409621284?language=en
• 关键词: Numerical; experimental; investigations; dimensionless; material

Compared to other manufacturing processes for plastic components, there are only few materials available for laser-based powder bed fusion (PBF/LB). The overall goal of the priority programme is to overcome this limitation. Numerous research groups are currently working on developing new powder feedstock materials and manufacturing methods. The complexity and material requirements of PBF/LB make the development of new powders difficult. To accelerate powder development, a better understanding of the process is necessary. In particular, the influence of material properties on processing behaviour is of interest. This enables optimizations in the development of polymeric feedstocks. The increased understanding of material-process relations allows to manufacture components reproducibly with improved mechanical properties.The main objective of the project is to develop dimensionless characteristic numbers (DCN) that can realistically represent the PBF/LB process and allow the definition of stable process windows depending on the material. In the first funding period, theoretical considerations and numerical simulations led to an increased understanding of material-process relationships. However, further investigations are necessary to take into account material parameters that have been neglected so far. In addition, effects that occur during multi-layer application are to be investigated in greater depth.The first sub-objective is to investigate the correlation of further intrinsic and extrinsic material parameters with the process. As extrinsic material parameters, the influences of the shape and size of the polymer particles on, in particular, the coalescence behaviour in the PBF/LB process are to be investigated. Intrinsic material parameters whose influence will be investigated are viscoelastic properties and crystallisation kinetics. In addition, the laser attenuation coefficient in different polymers or polymer blends is to be analysed in depth. Since there are no established measurement methods for this yet, an analysis method is to be developed. Numerical simulations will be used to investigate the influence of all the material parameters mentioned and to determine their respective relevance for processability.The second sub-objective is to validate the process windows derived from the DCN with further materials. Novel powders from cooperating groups are to be used for this purpose. In addition to validation, newly developed powders can thus be investigated regarding their processability.The third sub-objective focuses on the influence of the application of several successive layers. The steady-state melting and coalescence behaviour of ten layers will be investigated, which presumably depends on the time interval between the application of the layers.

与塑料部件的其他制造工艺相比，只有少数材料可用于基于激光的粉末床熔合（PBF/LB）。优先方案的总体目标是克服这一限制。许多研究小组目前正在开发新的粉末原料和制造方法。PBF/LB的复杂性和材料要求使得新粉末的开发变得困难。为了加速粉末的开发，有必要更好地了解该过程。特别是，材料性能对加工行为的影响是感兴趣的。这使得能够优化聚合物原料的开发。对材料-工艺关系的进一步理解使得能够以更高的机械性能可重复地制造部件。该项目的主要目标是开发无量纲特征数（DCN），以真实地表示PBF/LB工艺，并根据材料定义稳定的工艺窗口。在第一个资助期内，理论考虑和数值模拟导致了对材料-工艺关系的更多理解。然而，进一步的调查是必要的，以考虑到材料参数，一直被忽略了。此外，在多层应用过程中发生的影响将进行更深入的调查。第一个子目标是调查进一步的内在和外在的材料参数与过程的相关性。作为外在的材料参数，聚合物颗粒的形状和大小的影响，特别是聚结行为的PBF/LB过程中进行了研究。将研究其影响的内在材料参数是粘弹性和结晶动力学。此外，还将深入分析不同聚合物或聚合物共混物中的激光衰减系数。由于目前还没有确定的测量方法，因此需要开发一种分析方法。数值模拟将被用来调查的影响，所有的材料参数提到，并确定其各自的可加工性的相关性。第二个子目标是验证从DCN与进一步的材料派生的工艺窗口。来自合作团体的新型粉末将用于此目的。除了验证之外，还可以研究新开发的粉末的加工性能。第三个子目标关注连续几层应用的影响。将研究十层的稳态熔化和聚结行为，这大概取决于层的应用之间的时间间隔。