Investigating the effect of fused deposition modeling processing parameters using Taguchi design of experiment method

Fused Deposition Modeling (FDM) is an Additive Manufacturing (AM) technique that fabricates parts layer upon layer. The recent development of AM technologies is driving FDM from rapid prototyping to rapid manufacturing. However, building end-user functional parts using FDM proved to be a challenging task, which is due to having many processing parameters that may influence the parts' quality. It is challenging to use full factorial Design of Experiments (DOE) to investigate the influence when there are many processing parameters, especially when the processing parameters are not expected to behave linearly. In addition, to fully exploit the accurate processing parameters influence a large number of sample sets are required. In this paper, Taguchi's DOE is used to investigate the main effects of four processing parameters in the FDM process, those are the infill percentage, infill pattern, layer thickness, and extrusion temperature. The processing parameters influence is expressed in terms of the mechanical properties and dimensional accuracy of FDM parts fabricated. The material under interest is PLA filament fabricated using a commercial FDM 3D printer. In the presented work, we used Taguchi's L9 array that had 9 runs with 3 repeated specimens for each, hence a total of 27 specimens were fabricated using varying processing parameters. The dimensions of the fabricated specimens were compared with the 3D CAD model and then tested according to the ASTM D638 standard. The results showed that for generally better dimensional accuracy, a lower extrusion temperature, smaller layer thickness, lower infill percentage, and hexagonal infill pattern were required. In addition, current FDM fabrication process usually generates parts with larger dimensions as compared to the CAD model. On the other hand, to increase the strength of FDM parts, a higher extrusion temperature, an optimized layer thickness, a triangular infill pattern, and a higher infill percentage are required. Ductility can be improved by switching to rectilinear infill pattern and by increasing the layer thickness.