Design and Fabrication of a Lightweight Cantilever Beam Using Topology Optimization and Material-Extrusion Additive Manufacturing

Topology optimization (TO) combined with additive manufacturing (AM) enables the fabrication of lightweight structural components with prescribed load paths that are often difficult or impractical to achieve using conventional manufacturing. In this study, a cantilever-style beam subjected to a 0.5 kg end load was designed, optimized, and fabricated using material-extrusion additive manufacturing. A maximum-stiffness topology optimization with a prescribed mass-reduction constraint was performed using Altair Inspire, followed by manual CAD reconstruction to enforce manufacturability while preserving optimized load paths. The final design was fabricated with polylactic acid (PLA) using fused filament fabrication (FFF) without support structures. Finite element analysis predicted a peak von Mises stress of 7.02 MPa and a maximum displacement of 8.24 mm, corresponding to a factor of safety exceeding 7 relative to PLA yield strength. Compared to the initial design, the optimized beam achieved an 80% mass reduction while successfully supporting the applied load during physical testing. A comparative cost analysis further demonstrated that additive manufacturing reduced unit production cost by approximately 57% relative to conventional CNC machining for this geometry. The results highlight the effectiveness of integrating TO with extrusion-based additive manufacturing for producing structurally efficient, low-cost components.