Abstract Designing and manufacturing functional parts with enhanced mechanical property is a major goal of fused filament fabrication (FFF) for polymeric elastomers, which exhibits major advantages in producing such parts with a range of structures. But the unsatisfactory mechanical performance constrains greatly its real application and there is yet no consensus in the mechanical characterization of printed samples. This work takes the nozzle height as the considered factor and tests the tensile property of FFF-printed thermoplastic polyurethane (TPU). Rheological property of the TPU melt, represented here by die swell behavior and shear viscosity, were measured initially to obtain a preliminary assessment of the material suitability and an optimization of melt extrusion conditions for FFF processing. Then correlation between the cross-section profile of deposited bead and the tensile performance of printed sample were evaluated. Both the shape of deposited bead and the bonding strength of two adjacent beads are emphasized when explaining the measured tensile strength. The significance of molecular permeation efficiency at bead-bead interfaces, and bonding-releasing patterns between adjacent beads to the tensile failure of printed objects is discussed.

中文翻译：

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FFF印刷弹性体拉伸性能的实验分析

摘要 设计和制造具有增强机械性能的功能部件是聚合弹性体熔丝制造 (FFF) 的主要目标，其在生​​产具有一系列结构的此类部件方面具有主要优势。但不理想的机械性能极大地限制了其实际应用，并且在印刷样品的机械表征方面尚未达成共识。本工作以喷嘴高度为考虑因素，测试 FFF 印刷热塑性聚氨酯 (TPU) 的拉伸性能。最初测量 TPU 熔体的流变特性，在此由模头膨胀行为和剪切粘度表示，以获得材料适用性的初步评估和 FFF 加工熔体挤出条件的优化。然后评估沉积珠的横截面轮廓与印刷样品的拉伸性能之间的相关性。在解释测得的拉伸强度时，强调了沉积珠的形状和两个相邻珠的结合强度。讨论了珠-珠界面的分子渗透效率和相邻珠之间的键合-释放模式对印刷物体拉伸失效的重要性。