Mechanical performance of thin-walled TPMS structures fabricated via mSLA for advanced heat exchangers: Influence of geometry and resin

Triply Periodic Minimal Surface (TPMS) structures are gaining momentum in the development of next-generation heat exchangers, owing to their high surface-area-to-volume ratio and continuous cellular geometry. This study investigates the mechanical response of three TPMS geometries - Gyroid, Fischer-Koch S, and I-WP - manufactured via Masked Stereolithography Apparatus (mSLA) with minimal wall thicknesses (∼0.3 mm), enabling relative densities as low as 15%. Two commercial photopolymer resins were evaluated: a high-stiffness, glass-filled Rigid 10K resin, and a High Temp resin with enhanced thermal stability. Compression tests, designed to simulate hydrostatic load conditions, revealed marked differences in failure modes and mechanical behavior depending on both geometry and material. The Gyroid structure showed the highest peak specific stress and a progressive failure mechanism, while the Fischer-Koch S structure offered the best performance with the High Temp resin. Analysis of variance (ANOVA) confirmed a statistically significant interaction between geometry and material. These findings highlight the critical role of material-geometry synergy in designing TPMS-based heat exchangers capable of balancing strength, thermal resistance, and manufacturability.