3D printing polymers via fused filament fabrication (FFF) exhibits significant advantages such as low cost and high efficiency, thus FFF has become one of the most popular production methods in the 3D printing field. For a printing using a soft filament feedstock, it is important to understand how to optimize its fabrication process when attempting to improve the packing morphology of deposited melt strand and thus enhance the mechanical performance. This work intends to be a step forward obtaining a strategy for high-quality FFF printing without compromising printing efficiency for those filaments with low stiffness as well as low feeding stress. Using a commercial desktop printer, a facile method to reduce the porosity of FFF-printed thermoplastic polyurethane (TPU) parts was proposed by controlling printing parameters using specific TPU filaments with varying hardness. Tensile strength and tear resistance of the printed parts were measured to assess the optimization printing (OP) strategy. Owing to the significant reduction of porosity, less thermal degradation and higher molecular orientation in FFF, the tensile strength and tear resistance of the OP-printed parts were approximately 95% and 126.8% of those of parts fabricated via injection molding, respectively. Compared with the standard printing (SP) method, OP strategy was found to be effective in improving mechanical performance. The mechanism was then analyzed in terms of nozzle moving trajectory and filament loading ratio, with particular emphasis on feedstock in the continuity and stability of melt strand deposition. In addition, the correlation between residual porosity and mechanical performance of FFF-printed parts was established, providing direction for overcoming the practical limitations of FFF printing, thus paving a way to print high-quality elastomeric materials.

通过熔丝制造（FFF）3D打印聚合物具有低成本、高效率等显着优势，因此FFF已成为3D打印领域最受欢迎的生产方法之一。对于使用软丝原料的印刷，重要的是要了解如何在尝试改善沉积熔体线束的堆积形态时优化其制造工艺，从而提高机械性能。这项工作旨在在不影响低刚度和低进给应力的长丝的打印效率的情况下，获得高质量 FFF 打印的策略。使用商用桌面打印机，通过使用具有不同硬度的特定 TPU 长丝控制打印参数，提出了一种减少 FFF 打印的热塑性聚氨酯 (TPU) 部件孔隙率的简便方法。测量打印部件的拉伸强度和抗撕裂性以评估优化打印 (OP) 策略。由于 FFF 的孔隙率显着降低、热降解更少和分子取向更高，OP 打印部件的拉伸强度和抗撕裂性分别约为注塑成型部件的 95% 和 126.8%。与标准印刷 (SP) 方法相比，发现 OP 策略可有效提高机械性能。然后从喷嘴移动轨迹和灯丝加载比方面分析该机制，特别强调熔体流沉积的连续性和稳定性中的原料。此外，建立了FFF打印部件的残余孔隙率与机械性能之间的相关性，为克服FFF打印的实际局限性提供了方向，从而为打印高质量弹性材料铺平了道路。