Optimization of the control process parameters for PETG reinforced with short milled glass fiber in MEX additive manufacturing: impact on tensile and bending metrics

Abstract The increasing use of Material Extrusion (MEX) 3D printing for creating structural components has increased the need to improve the mechanical performance of the utilized materials. Herein, polyethylene terephthalate glycol (PETG) was reinforced with glass fibers, an efficient, cost-effective additive. The mechanical properties of such composites are sensitive to the printing parameters used, indicating that there is a need for systematic optimization of the printing process. This research focused on optimizing the mechanical performance of PETG/glass fiber composite parts manufactured with MEX 3D printing using a Taguchi design and a regression models (linear and reduced quadratic). The effect of raster deposition angle (RDA), nozzle temperature, layer height, and strand width on tensile and flexural properties of the composite parts was assessed. Of the four parameters, RDA was the highest ranked parameter affecting the mechanical metrics evaluated, but this was not the same for all the mechanical responses studied; the highest ranked parameter varied between the responses. Optimization resulted in significant improvements in mechanical properties; specifically, increases of 11% in tensile strength (45.5 MPa), 21% in Young’s modulus (237.75 MPa), 61% in flexural strength (89.86 MPa), and 56% in flexural modulus (1910.61 MPa). The tensile toughness improved by an impressive 92%, and the energy absorbed up to the prescribed flexural strain (in accordance with the respective standard ASTM D790) increased by 54%. The R 2 values were in the range of 82%-98%, while the confirmation runs deviation was less than 5%, confirming the accuracy of the proposed optimization framework. These results provide significant process optimization guidelines for the manufacturing of PETG/glass fiber parts using MEX for structural components.