High-Throughput Numerical Investigation of Process Parameter-Melt Pool Relationships in Electron Beam Powder Bed Fusion
Please login to view abstract download link
The reliable and repeatable fabrication of complex geometries with predetermined, homogeneous properties remains a major challenge in electron beam powder bed fusion (PBF EB). Although previous research already identified a variety of process parameter-property relationships, the underlying end-to-end approach omits the underlying thermal conditions. The local properties are however governed by the local thermal conditions of the melt pool. Therefore, the end-to-end approach is insufficient to transfer predetermined properties to complex geometries and different processing conditions. This work utilizes high-throughput thermal simulation for the identification of fundamental relationships between process parameters, processing conditions and the resulting melt pool geometry in the quasi-stationary state of line-based hatching strategies in PBF-EB. The semi-analytical thermal model applied to compute the emerging melt pool geometries is of reduced order, neglecting certain physical effects like fluid dynamics and evaporation, but in return enables an efficient, parallel computation and provenly produces promising results in the prediction of melt pool geometries [1]. Through a comprehensive study of more than 25 000 parameter combinations, including beam power, velocity, line offset, preheating temperature and beam diameter, process parameter-melt pool relationships are established. Based on the emerging melt pool geometries, processing boundaries are identified, whose characteristic shape and relationship to each other enable the precise identification of defect origins and the possibility to apply appropriate countermeasures in case of defect formation. Ultimately, the results of this high-throughput approach will provide guidelines for the effect of different processing conditions and processing strategies on the emerging melt pool geometries, the location of processing boundaries, and thus the final processing map. The main advantages compared to experimental investigations, besides the immense reduction of invested time and resources, are the ability to examine the effect of interdependent parameters such as the beam diameter isolated on entire process maps and to establish fundamental process parameter-melt pool relationships.