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Abstract Two types of defects that plague metal castings are hot tears and hot cracks, which necessitate repairs or rejection of the part. These defects form when high tensile stresses are present in the casting. Hot tears occur when the liquid metal film ruptures just prior to complete local solidification. Hot cracks form after complete local solidification. Alloy selection plays a role in forming these defects; however, the interaction between the casting and the mold is also important. Specifically, when the mold or core does not allow the casting to freely move, tensile stresses are formed within the casting. If high enough, these tensile stresses will cause a tear or crack within the cast metal. Hot tears or hot cracks are especially common when the casting geometry locks around a section of the mold or core. One method to deal with these conditions is to use lower strength sand in those regions prone to being locked in by the casting geometry. A potential method for achieving this objective is the use of an embedded lattice structure within the sand. This concept relies on sand having periodic voids that lower the sand’s effective strength compared to a fully solid section of bonded sand. A simple lattice structure was evaluated here having a regular pattern of parallel, evenly spaced rectangular holes in printed, furan-bonded silica sand. Evaluation of the concept involved a two-step process. First, a series of silica sand blocks having a regular pattern of through holes was printed and then tested by applying a compressive load until the sand blocks ruptured. The designs selected showed as much as an 89% reduction in mold compressive strength over solid sand blocks. Next, A206 (a hot-tear-sensitive aluminum alloy) I-beam castings were made. The web of these castings had a bulge at its mid-span to induce hot cracks or hot tears. X-ray images revealed cracks in most of the castings. The results showed that lattice geometry and casting thickness primarily controlled crack formation. Second-order effects, including quadratic effects and interactions among the various factors, provided an empirical model that consistently correlated to the measured length of hot tears/cracks. The findings demonstrate the ability of sand-embedded lattice structures to reduce or eliminate hot tears or hot cracks in castings. Finally, a brief discussion is presented on the impact of the lattice-structure design on casting distortion.