Phase-resolved partial discharge patterns are a valuable, non-destructive tool in determining defects of electrical insulation systems. One of the most frequent defects of polymer insulation is air voids inside the insulation material. Studies have been done previously to synthetically fabricate artificial air voids in polymer insulation materials to analyze phase-resolved partial discharge (PRPD) patterns using several different methods. It is useful to study the effect of the different sizes, shapes, and orientations of the void on PRPD patterns. In this study, poly-carbonate samples with incorporated air voids were fabricated using 3D printing techniques. Visualization and quantitative analysis of the fabricated air voids and the uniformity of the printed material were obtained by X-ray microtomography. PRPD patterns were obtained for different orientations of similarly-shaped air voids. This study opens up a novel fabrication method to prepare sample polymer insulation material with predetermined sizes, shapes, and orientations. Benchmark PRPD patterns are presented for several air void types.