Dou Hao, Cheng Yunyong, Ye Wenguang, Zhang Dinghua, Li Junjie, Miao Zhoujun, Rudykh Stephan
School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an 710072, China.
Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
Materials (Basel). 2020 Aug 31;13(17):3850. doi: 10.3390/ma13173850.
Three-dimensional (3D) printing continuous carbon fiber-reinforced polylactic acid (PLA) composites offer excellent tensile mechanical properties. The present study aimed to research the effect of process parameters on the tensile mechanical properties of 3D printing composite specimens through a series of mechanical experiments. The main printing parameters, including layer height, extrusion width, printing temperature, and printing speed are changed to manufacture specimens based on the modified fused filament fabrication 3D printer, and the tensile mechanical properties of 3D printing continuous carbon fiber-reinforced PLA composites are presented. By comparing the outcomes of experiments, the results show that relative fiber content has a significant impact on mechanical properties and the ratio of carbon fibers in composites is influenced by layer height and extrusion width. The tensile mechanical properties of continuous carbon fiber-reinforced composites gradually decrease with an increase of layer height and extrusion width. In addition, printing temperature and speed also affect the fiber matrix interface, i.e., tensile mechanical properties increase as the printing temperature rises, while the tensile mechanical properties decrease when the printing speed increases. Furthermore, the strengthening mechanism on the tensile mechanical properties is that external loads subjected to the components can be transferred to the carbon fibers through the fiber-matrix interface. Additionally, SEM images suggest that the main weakness of continuous carbon fiber-reinforced 3D printing composites exists in the fiber-matrix interface, and the main failure is the pull-out of the fiber caused by the interface destruction.
三维（3D）打印连续碳纤维增强聚乳酸（PLA）复合材料具有优异的拉伸力学性能。本研究旨在通过一系列力学实验研究工艺参数对3D打印复合材料试样拉伸力学性能的影响。基于改进的熔融长丝制造3D打印机，改变包括层高、挤出宽度、打印温度和打印速度在内的主要打印参数来制造试样，并给出了3D打印连续碳纤维增强PLA复合材料的拉伸力学性能。通过比较实验结果表明，相对纤维含量对力学性能有显著影响，复合材料中碳纤维的比例受层高和挤出宽度的影响。连续碳纤维增强复合材料的拉伸力学性能随着层高和挤出宽度的增加而逐渐降低。此外，打印温度和速度也会影响纤维基体界面，即拉伸力学性能随着打印温度的升高而增加，而当打印速度增加时拉伸力学性能降低。此外，拉伸力学性能的强化机制是部件承受的外部载荷可以通过纤维基体界面传递到碳纤维上。另外，扫描电子显微镜图像表明，连续碳纤维增强3D打印复合材料的主要薄弱环节存在于纤维基体界面，主要失效形式是由界面破坏导致的纤维拔出。
