Fan Congze, Shan Zhongde, Zou Guisheng, Zhan Li, Yan Dongdong
Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China.
State Key Laboratory of Advanced Forming Technology and Equipment, China Academy of Machinery Science & Technology, Beijing 100044, China.
Materials (Basel). 2020 Jun 26;13(12):2868. doi: 10.3390/ma13122868.
To further improve the mechanical properties of thermoplastic resin in additive manufacturing (AM), this paper presents a novel method to directly and quantitatively place the short fibers (SFs) between two printing process of resin layers. The printed composite parts with SFs between the layers was reinforced. The effects of single-layer fiber content, multi-layer fiber content and the length of fibers on the mechanical properties of printed specimens were studied. The distribution of fibers and quality of interlayer bonding were assessed using mechanical property testing and microstructure examination. The results showed that the tensile strength of the single-layered specimen with 0.5 wt% interlayered SFs increased by 18.82%. However, when the content of SFs continued to increase, the mechanical properties declined because of the increasing interlayered gap and the poor bonding quality. In addition, when the interlayered SFs length was 0.5-1 mm, the best reinforcement was obtained. To improve the interfacial bonding quality between the fiber and the resin, post-treatment and laser-assisted preheating printing was used. This method is effective for the enhancement of the interfacial bonding to obtain better mechanical properties. The research proves that adding SFs by placement can reduce the wear and breakage of the fibers compared to the conventional forming process. Therefore, the precise control of the length and content of SFs was realized in the specimen. In summary, SFs placement combined with post-treatment and laser-assisted preheating is a new method in AM to improve the performance of thermoplastic resin.
为了进一步提高增材制造（AM）中热塑性树脂的机械性能，本文提出了一种新颖的方法，可在树脂层的两个打印过程之间直接且定量地放置短纤维（SFs）。层间带有SFs的打印复合部件得到了增强。研究了单层纤维含量、多层纤维含量和纤维长度对打印试样机械性能的影响。使用机械性能测试和微观结构检查评估了纤维的分布和层间结合质量。结果表明，层间含0.5 wt% SFs的单层试样的拉伸强度提高了18.82%。然而，当SFs含量继续增加时，由于层间间隙增大和结合质量差，机械性能下降。此外，当层间SFs长度为0.5 - 1毫米时，获得了最佳增强效果。为了提高纤维与树脂之间的界面结合质量，采用了后处理和激光辅助预热打印。该方法对于增强界面结合以获得更好的机械性能是有效的。研究证明，与传统成型工艺相比，通过放置添加SFs可以减少纤维的磨损和断裂。因此，在试样中实现了对SFs长度和含量的精确控制。总之，SFs放置与后处理和激光辅助预热相结合是增材制造中提高热塑性树脂性能的一种新方法。
