Optimization of printing parameters for polyethylene terephthalate glycol thin honeycomb structures with shape-memory behaviors

This study investigates the optimization of 3D printing parameters for creating thin honeycomb lattice structures using polyethylene terephthalate glycol (PETG), a material known for its shape-memory capabilities. Experimental results demonstrate PETG’s high shape recovery, with elastic returns exceeding 95%, and underscore the critical influence of layer thickness and printing angle on both production efficiency and mechanical performance of printed structures. Increasing layer thickness notably enhanced stiffness and shape recovery due to fewer Z-axis discontinuities, reducing printing time. Conversely, adjustments to printing angle influenced printing speed and mechanical properties, with lower angles (particularly 0∘) yielding greater material continuity along the y-axis, leading to improved recovery after cyclic stress. Lower printing angles also prolonged exposure to heat, facilitating material homogenization. Cyclic tensile and flexural tests revealed that shape recovery improves in the second stress cycle due to residual stress accumulation, but declines in the third cycle as microfractures emerge. These microfractures, pronounced in thin lattice structures, highlight vulnerabilities associated with fine geometries. In summary, the combination of layer thickness and printing angle plays a crucial role in optimizing PETG lattice structures, with a 0∘ and a layer thickness of 0.3 mm providing the most favorable balance of mechanical performance and production efficiency.