Mechanical characterization of TPMS cellular structures produced using the lost pla method

This work investigates the design, manufacturing, and mechanical behavior of metallic lattice structures produced via the Lost-PLA replication technique. A parametric unit cell inspired by Triply Periodic Minimal Surfaces (TPMS) was defined, and two configurations were generated by varying a geometric parameter (b = 1.2 vs b = 0.8), resulting in different porosities (82% and 68%). The specimens were fabricated in AA6082 Al alloy using investment casting with sacrificial PLA models produced by FFF 3D printing. Dimensional characterization showed good agreement between CAD-estimated and experimental weights, confirming the accuracy and repeatability of the process. Static compression tests were performed on cylindrical specimens (60 mm × 46.5 mm) at 2 mm/min crosshead speed. The stress–strain curves revealed the characteristic response of cellular solids: an initial elastic regime, followed by a collapse plateau and final densification. Significant differences emerged between the two structures: the higher porosity configuration (Structure 1) displayed a stable plateau and absorbed on average 3.9 J/cm³ up to 60% strain, while the denser configuration (Structure 2) absorbed 30.9 J/cm³. These results highlight the strong influence of unit cell geometry on energy absorption capacity. The findings are consistent with the Gibson–Ashby model and with literature data on TPMS-based lattices fabricated by additive manufacturing, confirming that Lost-PLA is a suitable and cost-effective alternative for producing advanced cellular materials. The study demonstrates the potential of parameter-driven design to tailor mechanical performance, suggesting applications in lightweight protective components, crash absorbers and energy dissipating systems.