Measuring the Impact of Infill Pattern and Infill Density on the Properties of 3D-Printed PLA via FDM

In this research, 16 different infill patterns and 5 infill densities for each infill pattern (a total of 80 unique samples) were fabricated to be tested on microhardness, surface deformation and tensile tests. These samples were also simulated using finite element analysis in ANSYS for tensile tests for comparison with the experimental values. The change in values of microhardness and surface deformation across the samples was insignificant, indicating that these two parameters do not play a significant role in influencing these mechanical properties of the 3D-printed samples. The tensile strength of the samples experienced a steady increase as the infill density increased, with quarter cubic pattern demonstrating highest strength at 34.1 MPa for 100% density, while the lowest strength was recorded for lightning pattern at 10.9 MPa for 20% density. The difference between the experimental and simulated results was found to be 12%. Scanning electron microscopy was carried out to determine the reasons behind this difference, which revealed the presence of raster gap voids, partial neck growth voids and intra-bead voids, which form as melt flow and solidification characteristics of the filament are unable to sustain the ideal conditions for more than a few seconds in real life.