The effect of cutting parameters in CNC milling on mechanical properties of 3D-printed polylactic acid tensile test samples: axis speed, cutting direction and number of cutting tool teeth

Polylactic acid (PLA) filament is the most commonly used material in three-dimensional printers produced using the fused filament fabrication method. Studies on determining and developing the mechanical properties of 3D-printed PLA materials according to printing parameters continue in the literature. The innovation of this study is to determine the optimum cutting parameters with CNC (computer numerical control) milling of the test samples to determine the real mechanical properties of 3D-printed PLA tensile test samples. For this purpose, tensile test samples were produced using PLA filament with a 3D-printer, and the side edges of the produced samples were cut with a CNC milling machine using different cutting parameters. The cutting temperature, masses, surface roughness, and hardness of the products produced with this method were measured, and SEM images were taken from the cutting surfaces. As a result, it was determined that cutting temperatures and arithmetic average roughness values increased as the feed per tooth increased. It was determined that there was a 4 ~ 5 times increase in the elongation-at-break of the tensile test samples whose side surfaces were cut with a CNC milling machine. Among the parameters that are cut with CNC milling, the 5-4-500-Cl parameter, which has the lowest cutting temperature, feed per tooth, and the lowest arithmetic average roughness value, was chosen as the most suitable parameter for PLA material milling. The tensile modulus of the test sample in the selected parameter was determined to be 2.777 GPa, tensile strength was 48.442 MPa, and elongation-at-break was 15.043%.

Graphical abstract