Analytical Study and Experimental Verification of Shear-Thinning Ink Flow in Direct Ink Writing Process
Analytical Study and Experimental Verification of Shear-Thinning Ink Flow in Direct Ink Writing Process
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直写墨水剪切稀化流动的分析研究与实验验证
DOI：
10.1115/1.4056926
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Zhou, Chi
中科院分区：
文献类型：
--
作者：
Guo, Zipeng;Fei, Fan;Song, Xuan;Zhou, Chi
直接墨水写入（DIW）工艺是一种利用各种材料制造三维（3D）物体的简易增材制造技术。近年来，它的多功能性引起了学术界和工业界的极大兴趣。因此，为了优化处理分辨率和打印质量，在推进油墨流动行为方面投入了大量努力。然而，到目前为止，DIW过程中的物理现象并没有得到详细的揭示，在物理实验和其基础理论之间留下了研究空白。在这里，我们提出了一个全面的分析研究的非牛顿油墨流动行为在DIW过程中。不同的涡轮喷嘴的几何形状进行建模的比较案例研究。利用计算流体力学（CFD）模拟方法，揭示了油墨挤出过程中的剪切变稀特性。此外，我们还研究了粘性、剪切力和速度场，并分析了各种喷嘴模型的优缺点。在这些研究和分析的基础上，我们提出了一种改进的挤出喷嘴的几何形状，稳定的挤出和高印刷质量。一组DIW打印实验和流变特性进行了验证模拟研究。在这项工作中开发的结果提供了一个深入的了解，在DIW过程中的油墨流动行为，提供了宝贵的指导方针，优化物理DIW配置向高分辨率打印，从而提高DIW打印对象的性能。
Direct ink writing (DIW) process is a facile additive manufacturing technology to fabricate three-dimensional (3D) objects with various materials. Its versatility has attracted considerable interest in academia and industry in recent years. As such, upsurging endeavors are invested in advancing the ink flow behaviors in order to optimize the process resolution and the printing quality. However, so far, the physical phenomena during the DIW process are not revealed in detail, leaving a research gap between the physical experiments and its underlying theories. Here, we present a comprehensive analytical study of non-Newtonian ink flow behavior during the DIW process. Different syringe-nozzle geometries are modeled for the comparative case studies. By using the computational fluid dynamics (CFD) simulation method, we reveal the shear-thinning property during the ink extrusion process. Besides, we study the viscosity, shear stress, and velocity fields, and analyze the advantages and drawbacks of each syringe-nozzle model. On the basis of these investigations and analyses, we propose an improved syringe-nozzle geometry for stable extrusion and high printing quality. A set of DIW printing experiments and rheological characterizations are carried out to verify the simulation studies. The results developed in this work offer an in-depth understanding of the ink flow behavior in the DIW process, providing valuable guidelines for optimizing the physical DIW configuration toward high-resolution printing and, consequently, improving the performance of DIW-printed objects.