Optimizing 3D-Printed Auxetic Structures for Tensile Performance: Taguchi Method Application on Cell Size and Shape Orientation

Auxetic structures are characterized by their unique mechanical property of exhibiting a negative Poisson's ratio, which means they expand laterally when stretched and contract laterally when compressed, contrary to conventional materials. This distinctive behavior enables auxetic materials to possess enhanced mechanical properties such as improved energy absorption, shear resistance, and indentation resistance. This study is of special novelty as it is one of the few investigations examining the effect and optimization of shape orientation and cell size on tensile mechanical properties. For this reason, a total of nine different specimens were produced using three different cell sizes (3 mm, 2 mm, 1.5 mm) and three different shape orientations (0º, 45º, 90º) using a masked stereolithography (MSLA) printer, and their tension mechanical properties were investigated. The best cell size and shape orientation were determined by Taguchi's maximum signal-to-noise ratio (S/N) analysis, and the data was analyzed with the Analysis of Variance (ANOVA) test. Specifically, a cell size of 1.5 mm and a shape orientation of 90º delivered the best performance, with a maximum fracture force of 348.44 N and energy absorption of 224.91 J. This research contributes to optimizing 3D printing for improved mechanical performance and to the field of additive manufacturing.