Effects of process parameter variation on the surface roughness of polylactic acid (PLA) materials using design of experiments (DOE)

Abstract

3D Printing (3DP) is an additive manufacturing technology used to rapidly build parts that are designed using 3D modeling software. 3DP builds a part by adding one layer of the working material at a time until the process is complete. One main concern with 3D printed samples is the high levels of surface roughness, which can result in the rejection of parts by many precision manufacturing companies. The objective of this research is to use the Design of Experiment (DOE) to analyze which factors influence the surface roughness of the part built from a 3D printer. In this research, a two-level, three-factor, full factorial design of experiment is used to select the best combination of factors that will minimize the surface roughness of parts made from Polylactic Acid (PLA) materials. The selected factors are printing orientation, nozzle diameter, and infill percentage. Based on the preliminary result, it is determined all the factors and their two-factor interactions are shown to significantly affect the surface roughness. However, it is shown that the nozzle diameter has had the most effect on surface roughness. These results will be explained in terms of the optical microscopy of the processed PLA test specimens.