Investigation of Mechanical and Surface Properties of 3D-Printed Parts Aged Under Different Conditions (Coolant and Xenon Arc)

Predicting the changes in the performance of polymer-based 3D printing materials over time under industrial operating conditions is of critical importance. In particular, the chemicals present in the environments to which these materials are exposed and the duration of exposure directly affect their structural integrity and durability. In this study, the structural changes occurring in 3D-printed PLA Pro material as a result of aging in different environments (three different coolants used in the manufacturing industry and Xenon arc exposure) were investigated. The experiments were conducted using various analysis methods, including tensile and flexural tests, hardness, gloss, surface roughness, color, and mass measurements. The initial mass uptake behavior during the first 24 h of immersion was also evaluated. Finally, the changes in tensile strength (UTS) and flexural force of 3D-printed PLA Pro samples exposed to three different coolants for four different durations, and also subjected to 600 h of Xenon Arc aging, were evaluated using ANOVA. As a result, changes in the mechanical properties were observed under the different aging conditions.. Compared with the reference specimen (41.9 MPa), the highest tensile strength was obtained for the specimens immersed in the water-based fully synthetic Rhenus TY108S coolant for two weeks (48.4 MPa), while the lowest tensile strength was observed for the specimens immersed in the semi-synthetic FU51 coolant for one week (39.9 MPa). Following Xenon arc aging, the tensile strength was determined to be 47.5 MPa. Regarding the maximum flexural force results, an increase was observed in the specimens aged under Xenon arc exposure, whereas a decrease was observed in the specimens aged in the coolants. Hardness generally decreased with increasing immersion time in the coolants; however, the hardness values remained higher than that of the reference PLA Pro specimen throughout the aging period. The highest color change occurred in the Xenon arc-aged specimens, while no significant color change was observed in the specimens exposed to the coolants. The surface gloss of all specimens was classified as matte to semi-matte. Surface roughness increased following exposure to the coolants, whereas it decreased after Xenon arc aging. The mass of the specimens was more strongly affected by coolant exposure.