Digital Light Processing 3D Printed TPMS Foams With Uniform and Graded Struts: Impact of Polymer Infiltration and Aging on Mechanical Performance

This study investigates the design, fabrication, and mechanical characterization of triply periodic minimal surface (TPMS)‐based gyroid foams with uniform and graded strut architectures fabricated via Digital Light Projection (DLP) 3D printing. The printed thermoset polymeric foams were subsequently infiltrated with polylactic acid (PLA) using a solvent‐assisted approach and evaluated under 1‐day and 7‐day aging conditions to understand the role of infiltration and aging on the mechanical behavior. Compression testing revealed a transition from ductile elastic–plastic deformation in the as‐printed foams to brittle fracture in the infiltrated counterparts, accompanied by significant reductions in compressive strength and energy absorption capacity. The strength degradation was attributed to the chemical interaction between the solvent and printed matrix, leading to embrittlement and microstructural weakening over time. Graded foams exhibited superior energy absorption compared to uniform counterparts with minimum strut sizes, despite their comparable densities. Dimensional deviations, morphological features, and failure mechanisms were examined using SEM and optical microscopy. These findings underscore the critical influence of solvent‐induced degradation and strut topology on the mechanical performance of infiltrated polymeric TPMS structures, highlighting the need for optimized infiltration strategies in future multi‐material additive manufacturing applications.