Nargis Rifat Ara, Jack David Abram
Department of Mechanical Engineering, Baylor University, Waco, TX 76798, USA.
Polymers (Basel). 2023 Jun 29;15(13):2871. doi: 10.3390/polym15132871.
Polymer-based additively manufactured parts are increasing in popularity for industrial applications due to their ease of manufacturing and design form freedom, but their structural and thermal performances are often limited to those of the base polymer system. These limitations can be mitigated by the addition of carbon fiber reinforcements to the polymer matrix, which enhances both the structural performance and the dimensional stability during cooling. The local fiber orientation within the processed beads directly impacts the mechanical and thermal performances, and correlating the orientation to processing parameter variations would lead to better part quality. This study presents a novel approach for analyzing the spatially varying fiber orientation through the use of scanning electron microscopy (SEM). This paper presents the sample preparation procedure including SEM image acquisition and analysis methods to quantify the internal fiber orientation of additively manufactured carbon fiber-reinforced composites. Large area additively manufactured beads with 13% by weight large aspect ratio carbon fiber-reinforced acrylonitrile butadiene styrene (ABS) pellets are the feedstock used in this study. Fiber orientation is quantified using the method of ellipses (MoE), and the spatial change in fiber orientation across the deposited bead cross-section is studied as a function of process parameters including extrusion speed, raster height, and extrusion temperature zones. The results in the present paper show the results from the novel use of SEM to obtain the local fiber orientation, and results show the variation in alignment within the individual processed bead as well as an overall aligned orientation state along the direction of deposition.
基于聚合物的增材制造零件因其易于制造和设计形式自由，在工业应用中越来越受欢迎，但它们的结构和热性能通常局限于基础聚合物体系。通过在聚合物基体中添加碳纤维增强材料，可以减轻这些限制，这既提高了结构性能，又增强了冷却过程中的尺寸稳定性。加工珠粒内的局部纤维取向直接影响机械和热性能，将取向与加工参数变化相关联将有助于提高零件质量。本研究提出了一种通过使用扫描电子显微镜（SEM）分析空间变化纤维取向的新方法。本文介绍了样品制备过程，包括SEM图像采集和分析方法，以量化增材制造的碳纤维增强复合材料的内部纤维取向。本研究使用的原料是大面积增材制造的珠粒，其由重量比为13%的大长径比碳纤维增强丙烯腈丁二烯苯乙烯（ABS）粒料制成。使用椭圆法（MoE）对纤维取向进行量化，并研究沉积珠粒横截面上纤维取向的空间变化与包括挤出速度、光栅高度和挤出温度区域在内的工艺参数的函数关系。本文的结果展示了利用SEM获取局部纤维取向的新成果，结果显示了单个加工珠粒内排列的变化以及沿沉积方向的整体排列取向状态。
