Weight reduction in material extrusion composite parts: pin-bearing behavior analysis

This study investigated the performance of lightweight samples in pin-bearing tests. The samples were manufactured through Material Extrusion technology of nylon reinforced with short carbon fibers. Their design was based on infill strategy, density, and raster angle. Load–displacement curves and failure mechanisms were analyzed across configurations, with statistical methods applied to evaluate the influence of design factors on maximum stress, relative displacement, and stiffness. Results reveal distinct load–displacement behaviors and failure mechanisms, with deposition strategies tailored to specific final purposes. Specifically, the study identifies gyroid infill, 50% density, and a raster angle of 45° as the optimal solution for maximizing bearing stress. This configuration exhibits a weight and printing time reduction of 40% and 8% concerning the full sample, and a performance reduction in the range of 30–56%, considering both stress (28.2 MPa vs 65.8 MPa) and displacement reduction (9.4 mm vs 15.1 mm). Conversely, rectangular infill, 50% density and raster angle of 0° emerge as the optimal solution for minimizing displacement and maximizing stiffness. This configuration exhibits a weight and printing time reduction of 39% and 34%, in comparison to the full sample, and a performance reduction of about 65–70% (displacement of 4.6 mm at a maximum stress of 23.7 MPa). The triangular strategy can be used to reach elevated values for all output parameters (up to 25.9 MPa as maximum stress, 9.4 mm as maximum displacement, and 242.4 MPa for stiffness), with weight and printing time saving in the range of 41–54% and 34–36% respectively.