Peng Ju, Huang Jin, Wang Jianjun
Key Laboratory of Electronic Equipment Structure Design, Xidian University, Ministry of Education, Xi'an 710071, China.
Sensors (Basel). 2021 Apr 1;21(7):2441. doi: 10.3390/s21072441.
Piezoelectric three-dimensional inkjet printing has been used to manufacture heterogeneous objects due to its high level of flexibility. The materials used are non-Newtonian inks with complex rheological properties, and their behavior in the context of inkjet printing has not been fully understood: for example, the fact that the shear-thinning viscosity affects the droplet generation. Therefore, a control strategy coping with shear-thinning behaviors is needed to ensure printing consistency. In this paper, a novel model-based approach is presented to describe the shear-thinning ink dynamics inside the piezoelectric inkjet printhead, which provides the basis to design the excitation parameters in a systematic way. The dynamic equation is simplified into a quasi-one-dimensional equation through the combination of the boundary layer theory and the constitutive equation of the power-law fluid, of which the viscosity is shear-thinning. Based on this, a nonlinear time-varying equivalent circuit model is presented to simulate the power-law fluid flow rate inside the tube. The feasibility and effectiveness of this model can be evaluated by comparing the results of computational fluid dynamics and the experimental results.
由于具有高度的灵活性，压电三维喷墨打印已被用于制造异质物体。所使用的材料是具有复杂流变特性的非牛顿墨水，其在喷墨打印环境中的行为尚未得到充分理解：例如，剪切变稀粘度会影响液滴生成这一事实。因此，需要一种应对剪切变稀行为的控制策略来确保打印的一致性。本文提出了一种基于模型的新方法来描述压电喷墨打印头内部剪切变稀墨水的动力学，这为系统设计激励参数提供了基础。通过结合边界层理论和幂律流体的本构方程，将动力学方程简化为准一维方程，其中幂律流体的粘度是剪切变稀的。在此基础上，提出了一个非线性时变等效电路模型来模拟管内幂律流体的流速。该模型的可行性和有效性可以通过比较计算流体动力学结果和实验结果来评估。
