Eryildiz, MeltemKosa, ErginAkgün, İsmail CemYavuzer, Bekir2026-01-312026-01-3120250892-7057https://doi.org/10.1177/08927057241259761https://hdl.handle.net/20.500.12662/10504This study investigates a novel post-processing technique aimed at enhancing the mechanical properties of 3D-printed polypropylene-carbon fiber (PP-CF) composite parts. The method involves printing components with internal voids to reduce weight and printing time, subsequently filling these voids with a low-cost resin known for its superior mechanical properties. Through systematic experimentation varying infill density and pattern, key quantitative findings were obtained. Tensile strength generally increased with higher infill density, reaching a maximum of 55.664 MPa for the resin-filled triangle infill pattern with 60% infill density. Impact energy showed a decreasing trend with increasing infill density, with the highest impact energy of 0.5 J recorded for the resin-filled triangle infill pattern with 60% infill density. Microstructural analysis revealed that the triangle infill pattern at 60% infill density exhibited the most effective resin penetration, contributing to superior mechanical performance. These findings emphasize the importance of infill pattern selection in resin distribution and mechanical enhancement in 3D-printed composite materials. © The Author(s) 2024.eninfo:eu-repo/semantics/closedAccess3D printinginfill patternpolypropylene-carbon fiber compositepost-processingresin-filling techniqueArticle10.1177/089270572412597612-s2.0-1050017941148923Q187838