Investigation of the mechanical behavior of samples with different filling pattern and filling density produced from carbon fiber filament in 3D printer

In this study, tensile and compression tests were conducted to investigate the mechanical properties of carbon fiber samples produced using a three-dimensional (3D) printer. In the experiments, 5 different filling densities (20%, 40%, 60%, 80% and 100%) and 4 different pattern types (gyroid, triangle, zig-zag and grid) were used. Due to the difficulty of creating lattice structures with design programs, pattern types found in the device library have been used to provide ease of design for the user. Additionally, these patterns were chosen for comparison with studies done with other materials besides carbon fiber. Sample sizes were determined according to ASTM D638 for tensile tests and ASTM D695 for compressive tests. For the experimental sample material, ESUN brand EPA-CF 1.75 mm natural carbon fiber infused filament has been used. The printing parameters for the production of the samples with a 3D printer have been determined as follows: printing temperature of 265 ℃, build plate temperature of 85 ℃, and layer height of 0.2 mm. As a result, in studies conducted with 5 different filling ratios and 4 different pattern types, it was observed that as the filling ratio increased, the values of tensile stress, elastic modulus, yield stress, resilience modulus, and breaking stress also increased in the tensile test results. As the filler ratio decreased, an increase in elongation during rupture and elongation during tensile testing was observed. According to the results of the compression tests, the elastic modulus, resilience modulus, and yield strength values of the samples with 100% and 80% filler ratios were measured to be higher than those of the samples with 60%, 40%, and 20% filler ratios. When comparing tensile and compression tests, it was observed that the compression yield stresses were higher than the tensile yield stresses.