Impact of process parameters and heat treatment on fused filament fabricated PLA and PLA-CF

The fused filament fabrication 3D printing technique yields low mechanical strength components as a result of the layer-by-layer building process. The choice of appropriate pre-processing and post-processing procedures resulted in a significant improvement in the mechanical attributes. In this work, the effects of process parameters namely infill density, pattern, extruder temperature, layer thickness, and print speed on the ultimate tensile strength of polylactic acid and carbon fiber polylactic acid components were analyzed. For both the filaments, the maximum mechanical strength was found at 90% infill volume for the gyroid infill with a layer height of 0.1 mm at a print speed of 30 mm/s. The tensile properties were higher in carbon fiber reinforced tensile samples than in standard polylactic acid. The influence of thermal annealing on the mechanical strength of tensile samples (ASTM D638 Type IV) was also examined. Annealing polylactic acid samples at 95 °C for 60 min demonstrated a maximum tensile strength of 38.27 MPa, representing a 23.02% increase. Similarly, annealing reinforced thermoplastic samples at 95 °C for 120 min resulted in ultimate tensile strength of 42.49 MPa, representing a 14.01% increase. Heat treatment settings that are optimized can considerably improve the mechanical characteristics of the fused filament fabricated end-use products thereby enhancing the potential of the 3D printing sector.