EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Metal Additive Manufacturing (MAM) processes are becoming widely used not only at Lab scale but also at production level. The most used MAM methods are Laser Powder Bed Fusion (LPBF) and Direct Energy Deposition (DED). The feedstock material for both additive manufacturing methods is metal powder. The quality of the powders has to be characterized before printing to reduce process uncertainty and optimize the printed products. Hence, size distribution and shape of the metallic particles are key physical properties to evaluate. Several characterization techniques exist to measure those properties. However, due to the nature of each method, different values may be obtained even for the same sample. The present study analyses experimental 2D and 3D characterization methods. Laser Diffraction (LD), Scanning Electron Microscopy (SEM) and High-Resolution X-Ray Computed Tomography (CT) are used to analyze different Stainless-Steel 316L powders. The image analysis related to the SEM and X-Ray CT methods are strongly affected by the post-processing route. This study analyzes the images using different strategies and software (ImageJ and Matlab) followed by a comparison to the LD method with the aim of increasing the accuracy of the measurements.
The result of the study proposes a robust measurement strategy for characterizing particle size distribution and morphology that fulfills the requirements of the MAM process, and guidelines to overcome the shortcomings of the different techniques are established.