THREE-DIMENSIONALLY PRINTED CRYSTAL MODELS

Minerals are formed in one of six crystal systems: Triclinic, Monoclinic, Orthorhombic, Tetragonal, Hexagonal, Isometric. Models of the six crystal systems are utilized in a Mineralogy course at Wilkes University. Rising enrollment coupled with deteriorating Krantz precision-cut wood crystal models have created a need to replace and expand the inventory of models. As an alternative to the highly priced and easy to damage precision-cut wood models, replica models were researched using 3D printing technology. To begin, seven models were chosen for replication. Each model represented the highest symmetry crystal class within the six crystal systems (including Trignal subsystem): Pinacoidal (Triclinic), Prismatic (Monoclinic), Rhombic-dipyramidal (Orthorhombic), Ditetragonal-dipyramidal (Tetragonal), Dihexagonal-dipyramidal (Hexagonal), Hexagonal-scalenohedral (Hexagonal), Hexoctahedral (Isometric). Each of the seven models was drawn using Autodesk’s 3D Modeling AutoCAD drawing program. Measurements for the drawings were determined using the original wood models, a caliper, unit cell parameters, and the crystallographic symmetry elements of each model. The AutoCAD drawing files were converted to a file compatible with the university’s Dimension 3D Printer: SST 768 using commands in the AutoCAD program. Those files were loaded into the university’s 3D printer software. The software determined which orientation was best for the printer to create each model and a batch of models was printed in solid plastic over 9 to 12-hour blocks of time. A symmetry analysis of each printed model was performed to ensure accurate replication of the corresponding wood model. Our results indicate that 3D printing is an accurate and viable alternative to standard wood-cut models.