<p>Using virtual prototyping and numerical simulation, this study presents the optimization of the feeding system employed in an unconventional investment casting process, which applies centrifugal force perpendicular to the rotation axis to inject molten metal into refractory plaster molds. The objective is to enhance the manufacturing of a miniaturized S-shaped auxetic structure. Auxetic structures, known for their negative Poisson’s ratio, are widely used across various industries, and their complex geometry requires a high-precision casting process. The metal alloy used is an aluminum bronze with shape memory functionality (Cu–Al–Mn SMA). Numerical simulation was performed using a commercial simulation software, ProCAST^®, and experimental parameters as input data. In this analysis, ten design of casting models were proposed, with the fifth model proving ideal, eliminating shrinkage defects, filling failures, and unwanted circulation, while also reducing injection time.</p>