Multi - Objective Topology Optimization and Microstructural Characterization of Additively Manufactured PLA, PETG and ABS for Progressive Weight Reduction

This study investigates the effect of topology optimization (0-50% weight reduction) on the mechanical performance of fused deposition modelling (FDM) fabricated polylactic acid (PLA), polyethylene terephthalate glycol (PETG), and acrylonitrile butadiene styrene (ABS) for lightweight biomedical structural applications. Standardized specimens were manufactured and evaluated through tensile, compressive and flexural testing, supported by finite element analysis and scanning electron microscopy (SEM) to examine structural behavior and microstructural characteristics. The results indicate that PLA exhibited the highest tensile (60 MPa) and flexural strength (90 MPa), while ABS showed relatively stable compressive performance. At full material density (100%), PLA showed the highest tensile strength (60 MPa), followed by PETG (55 MPa) and ABS (45 MPa). With a 50% weight reduction, tensile strength decreased to 36 MPa for PLA and PETG and 32 MPa for ABS. In compression, ABS retained a compressive strength of 49 MPa even after 50% material removal through topology optimization, while PLA decreased from 70 MPa to 49 MPa and PETG from 68 MPa to 50 MPa. A similar decreasing trend was observed in flexural strength, where PLA reduced from 90 MPa to 58 MPa, PETG from 85 MPa to 58 MPa and ABS from 80 MPa to 58 MPa. An optimal topology optimization range of 30–40% was identified, achieving substantial weight reduction while maintaining mechanical performance. This study provides a systematic multi-material comparison and identifies an optimal topology optimization range for lightweight polymer structures intended for future biomedical applications.