Comparison of X-ray computed tomography and conventional methods for the geometrical characterization of metal powder for additive manufacturing

Among additive manufacturing technologies, laser powder bed fusion (LPBF) has experienced extensive interest in recent years from a wide range of industrial sectors, including aerospace and biomedical. One important aspect influencing the performances of processes and products is the quality of the feedstock material. In particular, metal powder used in LPBF should have shape and size promoting good flowability and packing behaviour, which have a direct impact on density, surface finish and mechanical properties of the fabricated parts. X-ray computed tomography (CT) is an advanced technique that enables holistic three-dimensional characterizations of metal powder, with simultaneous measurement of size and shape. The geometrical measurement accuracy of X-ray CT powder characterization is investigated and enhanced in this work, starting from the comparison with laser diffraction and scanning electron microscopy.