Systematic approach for the characterization of additive manufactured and injection molded short carbon fiber-reinforced polymers under tensile loading

摘要

Material extrusion-based additive manufacturing techniques such as fused deposition modeling or fused filament fabrication are developing from prototyping applications to serial components. The aim of this study is to properly characterize an additively manufactured polymer with the corresponding process-induced defects. To this effect, varied manufacturing orientations of fused filament fabrication were tested with a single-batch material manufactured by injection molding serving as a reference. Scans were carried out via micro-computed tomography to assess the void content and distribution with respect to quality. Local material performance was investigated via quasi-static and cyclic tests under tensile loading. The quasi-static tensile tests indicated a significant reduction of Young's modulus, tensile strength, and strain at fracture for the additively manufactured polymer. The mechanical investigations with cyclic loading intensified this trend of clear reduced mechanical properties due to process-induced defects. The quality assessment revealed void volume contents of the additively manufactured polymer of up to 6.5% and a void distribution dependent on manufacturing orientation. The results of this study are valuable as design guidelines for highly stressed components and serve as a basis for further characterizations of process-induced defects.