Manufacturing parameters’ effects on the flexural properties of 3D-printed PLA

Abstract In this study, the effects of infill ratio, layer thickness, nozzle temperature, and raster angle on the flexural strength of polylactic acid material were investigated through microstructural analysis. A total of 10 different sample groups were produced, changing the parameters of the filling ratio (20, 40, 60, 80 %), layer thickness (0.15, 0.20, 0.25, 0.30 mm), nozzle temperature (210, 220, 230 °C), and raster angle (±45°, 0/90°). Three-point bending tests were conducted using the Shimadzu bending machine, and the results were used to calculate maximum bending stress, modulus of elasticity, and strain values. The results showed that the values of maximum bending stress and modulus of elasticity vary significantly with changes in layer thickness, filling ratio, nozzle temperature, and raster angle. The Scanning Electron Microscopy (SEM) images were obtained from the longitudinal cross-section of the samples in the failure area. The obtained images were used to identify the gaps between beads, voids, porosity, filament rapture, pull-out breakage, elongation, and necking patterns on the samples. The variations in flexural properties were verified by using SEM micrographs in the failure area.