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A comparison of three-dimensional–printed porous rocks with nano x-ray computed tomography: Silica sand, gypsum powder, and resin

To date, a variety of 3-D printing methods and materials have been utilized to replicate natural rocks, yet no study has compared their outputs. Such work can enable us to select the most appropriate printing technique and material combinations to ensure better results when natural rocks are substituted with replicas. The present study compares binder jetting and stereolithographic (SLA) 3-D printing methods in the manufacturing of a porous rock model. The materials employed are gypsum powder and silica sand for the binder jetting technique, and resin for the SLA method. First, a digital rock model based on Berea Sandstone was created with computed microtomography imaging, then the image was printed using the aforementioned methods and materials. The replicas were examined by computed nanotomography imaging to compare the resemblance of internal pore structures to the natural specimen. It was found that powder-based printing with gypsum created an output that was comparable only on the exterior portions to the reference model, silica sand failed in the interior boundaries because of loosely packed particles, and the resin-based model was the most similar to the reference in terms of pore shape and geometry. Ultimately, this study should help lay out general guidelines in selecting appropriate purpose-based printing techniques and materials to benefit the field of geosciences.