Speed-controlled printing strategy for functionally graded TPMS structures: A process optimization perspective

This work introduces a novel, process-driven strategy for manufacturing functionally graded Triply Periodic Minimal Surface (TPMS) structures via fused filament fabrication, based on controlling local density through printhead speed modulation. Unlike conventional approaches that rely on geometric variation or toolpath complexity, this method maintains a constant slicing geometry while adjusting the printhead velocity to vary material deposition rate: slower speeds generate higher density, while faster speeds result in reduced material accumulation. Compared with uniform counterparts, the graded specimen reduced build time by ∼28 %. Moreover, for the same target density map, replacing line-multiplication grading with speed-modulation can yield up to ∼80 % shorter slicer-estimated build time. Mechanical behavior was assessed through three-point bending tests on specimens with constant densities (10 %, 20 %, 30 %) and on functionally graded samples with an average density of 10 %. Results show that graded structures, despite their low material content, achieved significantly improved performance over uniform low-density samples, approaching the strength and stiffness of denser configurations. These findings highlight the potential of velocity-based deposition control as an effective tool for rapid manufacturing of lightweight, architected materials with tailored mechanical properties. The approach provides a transferable insight into process optimization for additive manufacturing, supporting the development of faster and more efficient design-to-production workflows.