Design of Flexible TPU-Based Lattice Structures for 3D Printing: A Comparative Analysis of Open-Cell Versus Closed-Cell Topologies

This study presents a comparative analysis of the influence of open-cell and closed-cell topologies on the manufacturing quality and resultant elasticity of 3D printed thermoplastic polyurethane (TPU) lattice structures. Lattice samples were designed based on various open-cell and closed-cell configurations, varying in unit cell size and fabricated using extrusion-based additive manufacturing (AM) techniques. A microscopic analysis was conducted to assess manufacturing defects, while mechanical compression tests were performed to characterize the elasticity of the samples. The correlation between the obtained results enabled the evaluation of the relationship between the manufacturability of lattice topologies and their stiffness. The findings reveal substantial differences in the manufacturability of the topologies, with open-cell structures exhibiting more pronounced defects. Additionally, the unit cell size and the resulting density of the samples were found to provide design advantages, as closed-cell topologies demonstrated superior load resistance. The accumulation of manufacturing defects was identified as a critical factor influencing deviations in stiffness measurements. This study establishes a foundational framework for lattice structural design, emphasizing the impact of cell topology and unit cell size on mechanical performance. The significance of this research lies in its contribution to the optimization of 3D printed TPU-based lattice structures, providing valuable insights for product design applications.