No abstract

Accurate characterization of the mass transport properties of additively processed sand molds is essential in order to achieve reproducibility of the produced castings and control of gas defects in foundry industries. The present work highlights the potential use of X-ray microcomputed tomography (µ-CT) to characterize the evolution of permeability and some major microstructural features of such additively processed sand molds. The evolution of mass transport properties of sand mold samples under specific processing conditions met in additive manufacturing and its influence on the porosity, the permeability, the tortuosity, and the pore and throat size distributions were characterized from 3D images provided by X-Ray µ-CT. The obtained results showed that the mass transport properties of additively processed sand molds can be closely predicted by using non-destructive in situ methods, such that improvements to the casting can be made to create more optimized 3D printed structures for foundry applications.

We propose a multiresolution X-ray imaging method designed for non-destructive testing/evaluation (NDT/NDE) applications which can also be used for small animal imaging studies. Two sets of projections taken at different magnifications are combined and a multiresolution image is reconstructed. A geometrical relation is introduced in order to combine properly the two sets of data and the processing using wavelet transforms is described. The accuracy of the reconstruction procedure is verified through a comparison to the standard filtered backprojection (FBP) algorithm on simulated data.

We propose a method for multiresolution image reconstruction in X-ray micro computed tomography (microCT). It can have a variety of applications, from material characterization to small animal imaging studies. The main idea is to recover an overall image of the sample with a coarse resolution, and with a fine resolution for a region-of-interest (ROI). In a zoomin CT type setup, two sets of data are used, taken at different magnifications ratios. They are combined with the help of an analytical relation and the reconstruction is an extension of the filtered back-projection (FBP) algorithm. We present results with simulated data, some performance aspects and a simple noise analysis.