Mechanical Characterization of FDM Printed Fiber Reinforced Polymer

Abstract

Additive manufacturing with fused filament fabrication (FFF) is becoming a highly adopted method for production of lightweight polymer components with complex geometries. Regardless of its advantages, the process still involves dimensional deviations that limit the application of the polymers produced by FFF in accuracy-sensitive fields. PETG (Polyethylene terephthalate glycol) can be reinforced with continuous carbon fiber (CCF). The reinforcement further enables the enhancement of stiffness and strength but the influence of CCF on dimensional accuracy and mechanical performance of printed parts were not yet deeply investigated. The project measures the geometrical accuracy and the mechanical behavior of PETG and continuous carbon fiber reinforced PETG (CCF -PETG) printed using an Anisoprint A4 system. A dimensional analysis on the artifact 80 x 80 x 4 mm was held using ZEISS T-scan. First experiments used a Taguchi based experimental design to determine the influence of printing speed and extrusion temperature on dimensional accuracy. Initial results show that CCF-PETG always depicts a smaller dimensional deviation on all axes compared to PETG. These advancements have been correlated with slower print speeds, the greater rigidity of continuous fibers, and alleviated thermal deformation during co-extrusion. Tensile testing of continuous carbon fiber-reinforced PETG (CCF-PETG) specimens printed at 0°, 15°, 30°, 45°, and contour-only fiber orientations revealed a strong dependence of mechanical properties on fiber angle, with 0° specimens achieving the highest mean ultimate tensile strength of 269.3 MPa and a Young's modulus of 44.62 GPa. Both UTS and stiffness decreased monotonically with increasing fiber angle. These results confirm that fiber orientation is an important parameter governing the mechanical performance of FFF-printed CCF-PETG, and that contour-only configurations provide substantial strength and stiffness improvements over the unreinforced polymer.