X-ray computed tomography (CT) is a nondestructive technique that provides a unique means for the quantitative characterization of sand molds. Information relative to both the formation and performance of these molds can be gathered in a quantitative and reproducible way. The goal of the current study was to extend previous work in order to establish a quantitative correlation between the mass density of sand molds and scanned density, as measured by CT A quantified description of sand-mold uniformity is critical to an improved understanding of mold performance during casting operations. This requires the development of appropriate procedures for accurate and repeatable quantification. Grade 1L5W lake sand was used to prepare samples for the CT-density calibration. We deliberately chose to process this material into different types of standards that spanned a wide density range and produced an accurate, highly linear calibration quite similar to the forms previously derived for alumina and zinc oxide. We then sought the more aggressive application of this technique to a complex step cone mold. CT provided a clear visualization of the three-dimensional distribution of low and high densities within the scanned volume. Density gradients in molds formed by blowing sand appear to depend on (1) restrictions in flow, (2) the density of active flows at the end of the blow molding process and (3) the distance of the flow from the source of the system pressure.
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