Optimization of fused deposition modelling process parameters and the effect on residual stresses of built parts

Abstract

Fused deposition modelling (FDM) is one of the most used additive manufacturing techniques for the fabrication of functional parts from composite filaments. Despite the widespread application spectra, FDM is still limited in its applicability due to inherent problems, one of which is the significant accumulation of residual stresses during part building. Residual stresses are generated due to thermo-cyclic loading in subsequent layers. The effect of residual stresses is significant for the mechanical integrity of the manufactured parts. Since it is impossible to manufacture parts without internal residual stresses, it is prudent to optimize the process parameters that would result in minimal residual stresses. In this study, Digimat additive manufacturing 2020 software with Taguchi design of experiment was used to predict the effect of printing temperature, layer thickness, and print speed on the generated residual stresses. Generic algorithm was used to determine the optimum combination levels for the minimum residual stresses. Results showed a near convergence between simulation and experimental residual stress values with an error of 3.7 %. The mechanical properties of 3D printed carbon fiber composite products were found to have tensile strength; 71.48 MPa, compressive strength; 135.8 MPa, Young’s Modulus; 7.6 GPa, and percentage elongation; 1.86 %. These properties fell within the acceptable range for the actual parts to be replaced. The results of this study will serve as a pragmatic approach to 3D printing of components devoid of trial and error strategies that have currently slowed the adoption of the FDM technique as a rapid prototyping tool for enhanced manufacturing.