Flexural, pull-out, and fractured surface characterization for multi-material 3D printed functionally graded prototype

This paper reports the flexural, pull-out, and fractured surface characterization for multi-material three-dimensional printed functionally graded prototypes, which is prepared on fused deposition modeling setup. The work is an extension of previously reported study in which different thermoplastic matrices of polylactic acid blended with polyvinyl chloride, wood dust, and Fe3O4 powder (as multiple blended feedstock filaments) have been prepared separately with twin screw extrusion for possible three-dimensional printing. Finally, functionally graded prototypes with alternative layers of polylactic acid (01 layer), polylactic acid + polyvinyl chloride (01 layer), polylactic acid + wood dust (02 layers), and polylactic acid + Fe3O4 (02 layers) were three-dimensional printed on fused deposition modeling for flexural samples as per ASTM D790. With regard to process parameters of fused deposition modeling (in this case study), infill density of 100%, infill angle of 45 degrees, and infill speed of 50 mm/s were the optimized processing conditions. The results of study suggest that maximum flexural strength 26.92 MPa and pull-out strength 18.11 MPa were observed for functionally graded multi-material three-dimensional printed prototypes. From fractured surface analysis and hardness result, it has been ascertained that higher infill density and lower infill angle lead to better diffusion of material in layer-by-layer fashion resulting into less void formation and better flexural and pull-out performances. The novelty of this work lies in accessing the behavior of three-dimensional printed prototypes having different functional ability for each layer, with a potential to replace hybrid blend-based prototypes.