Characterization of defects/porosity in additive manufactured components using computer tomography

The key barrier for many industries in adopting additive manufacturing technologies is the lack of quality assurance and repeatability. Defect/porosity analysis is the most important inspection step for any additively manufactured components.
This paper presents a method for the detection of defects/porosity in additive manufactured components using computer tomography. A Nikon XTH225 industrial CT was used to analyse the relative size and location of the defects and assess the capability of the inspection process based on different levels of X-ray detector magnification. To reduce the number of process variables, all the measurement process parameters, such as filament current, acceleration voltage and X-ray filtering material and thickness, are kept constant. The acquired data processing, surface determination process and defect analysis was carried out using the VgStudio Max (Volume Graphics, Germany) software package.
One Ti6AL4V component built using an Arcam Q10 electron beam melting machine (EBM) was used. The results obtained from the XCT scan are compared to the physical defect analysis, by sectioning the component and confirming pore size and location using focus variation interferometry. The effect of surface determination, repeatability and results’ accuracy are discussed. The main focus of the study is on providing best practice regarding the selection of inspection parameters such as magnification to accurately perform the defect detection.