Evaluation of the mechanical behavior of fused deposition modeling (FDM)-printed virgin and recycled PLA parts using factorial design

This work evaluated the mechanical behavior of FDM-printed parts of virgin (v-PLA) and recycled PLA (r-PLA) based on a factorial design, with ultimate tensile strength (UTS) as the response variable and PLA type, geometric pattern (linear, tridimensional, and hexagonal), and infill percentage (33%, 66%, and 100%) as factors. The v-PLA results showed that the strength increased as the infill was greater or with the geometric pattern change from tridimensional (25–37 MPa) to linear (31–44 MPa) and hexagonal (35–46 MPa); however, r-PLA showed minimal variation in UTS regardless of the factors and levels evaluated (1723 MPa). The optimal UTS (46 MPa) was achieved with v-PLA, hexagonal pattern and 100% infill, while fracture analysis indicated high concentration of air bubbles in r-PLA. Understanding the mechanical behavior of r-PLA based on statistical reliability contributes to the advancement of efficient design and sustainable manufacturing technologies.