A Comparative Study on the Effects of Material Extrusion Processing Parameters on the Mechanical Behavior of Recycled Polylactic Acid and Polyethylene Terephthalate Glycol

ABSTRACT In recent years, the importance of recycling in mitigating harm to ecosystems and supporting sustainability has been growing worldwide. This study presents the effects of different material extrusion parameters on hardness, ultimate tensile strength (UTS), resilience, toughness, and modulus of elasticity in recycled polylactic acid (rPLA) and polyethylene terephthalate glycol (rPETG) samples produced via additive manufacturing. Regression analyses were performed to evaluate the effects of infill rate, layer height, and raster orientation. Subsequently, the samples were retested to verify the accuracy of the parameters obtained from the analysis. The most sensitive parameters for hardness were layer height and infill rate while UTS and toughness were directly proportional to the infill rate. The highest toughness, UTS and resilience values were obtained at 90° raster orientation, 0.1 mm layer height and 100% infill rate for both materials. These values were 286 MJ/m 3 , 57 MPa, and 85.5286 MJ/m 3 for rPLA and 232 MJ/m 3 , 53.8 MPa, and 139.88 MJ/m 3 for rPETG. In addition, the regression analysis revealed that the relative maximum error values for the validation sample were 10% for toughness, UTS, and resilience.