Continuous fiber-reinforced composites 3D printing can significantly improve strength but make materialize recycling more difficult. This study explores the feasibility of recycling and remanufacturing in practical applications by simulating the change in mechanical properties during outdoor aging of continuous aramid fiber-reinforced 3D printed parts. First, a Fermat's Spiral based globally continuous path was used to fabricate recyclable fiber-reinforced prints. Then, the continuous aramid fiber-reinforced PLA (CF/PLA) composites were recycled from the printed parts and re-impregnated in the subsequent production. Finally, the CF/PLA composite specimens were exposed to UV irradiation and moisture cycling in an aging test chamber, and the aging process of the whole experiment lasted for 516 h. It was found that for the first recycled and remanufactured specimens, the tensile strength was 204 MPa, which was higher than that of the originally printed specimens (196 MPa), and the flexural strength and modulus were 159 MPa and 6.4 GPa, higher than those of original specimens, which were 141 MPa and 5.6 GPa, an increase of 12.77% and 14.29%, respectively. For the specimens aged 172, 344, and 516 h, the tensile strength increased by 4.32%, 3.60%, and 17.36%, respectively after recycling and remanufacturing. The reduction rate of the tensile strength of the remanufactured specimens was 15.3% lower than that of the raw materials in the aging process. Our experiments estimated the change in properties of remanufactured specimens from recycled fiber-reinforced materials after natural aging, demonstrating the feasibility of the manufacturing process for recycled fiber-reinforced materials in practical applications.

中文翻译：

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可回收纤维增强 3D 打印性能变化的实验研究

连续纤维增强复合材料 3D 打印可以显着提高强度，但使回收变得更加困难。本研究通过模拟连续芳纶纤维增强 3D 打印部件户外老化过程中机械性能的变化，探索回收和再制造在实际应用中的可行性。首先，使用基于 Fermat 螺旋的全局连续路径来制造可回收的纤维增强印刷品。然后，连续芳纶纤维增强 PLA (CF/PLA) 复合材料从打印部件中回收，并在后续生产中重新浸渍。最后，CF/PLA 复合材料试样在老化试验箱中进行紫外线照射和水分循环，整个实验的老化过程持续 516 h。结果发现，对于第一个回收再制造的试件，抗拉强度为 204 MPa，高于最初打印的试件（196 MPa），弯曲强度和模量分别为 159 MPa 和 6.4 GPa，高于那些原始试样的压力为 141 MPa 和 5.6 GPa，分别增加了 12.77% 和 14.29%。对于时效为 172、344 和 516 h 的试件，在回收和再制造后，抗拉强度分别提高了 4.32%、3.60% 和 17.36%。再制造试样在时效过程中抗拉强度的降低率比原材料降低15.3%。我们的实验估计了再生纤维增强材料在自然老化后再制造试样的性能变化，