Conceptualization of a Measurement Procedure for Determination of Characteristic Properties of SLM Produced Parts by Means of Computed Tomography

Selective Laser Melting (SLM) is an Additive Manufacturing (AM) process, which enables the efficient fabrication of metallic parts with high geometric complexity and functional interior structures. The process is already established in high revenue industries such as aerospace and medical engineering. These industries are however highly regulated and require meticulous quality assurance. Currently, there are many different methods to investigate individual quality aspects of SLM produced parts. Due to the high complexity of these components, conventional nondestructive testing methods only deliver information limited to the investigated regions of the part, which are insufficient for providing statements on the overall quality. Furthermore, these investigations are very time consuming and require different measuring instruments. An abridged measurement procedure is therefore needed to increase the industrial application of the SLM-process. In this paper, a measurement procedure for simultaneous determination of structural and geometrical properties by means of X-ray microcomputed tomography (microCT) is conceptualized. The investigation considers structural properties such as porosity and defects along with geometrical properties, including dimensional and shape accuracy as well as surface quality. By combining all these investigations into one single, holistic quality inspection, significant time savings are expected. A miniaturized test geometry is designed and evaluated regarding the feasibility of the suggested approach. Limitations due to atomic mass and physical density of the sample material in accordance with the used microCT are discussed. It is further noted that the proposed holistic measurement procedure is applicable to other materials such as plastics and other AM processes.