The Simulation Of Electrohydrodynamic Jet And The Printing Experiments Of Piezoelectric Thick Film Micro Structures

Electrohydrodynamic jet printing is a kind of additive manufacturing technology based on the electric hydrodynamic effect, which uses the stable and fine jet to realize material printing. The jet is generated by the fluid under the effect of electric field force and mechanical force. Electrohydrodynamic jet printing has many advantages, such as normal pressure and temperature, high resolution, and wide material adaptability. These advantages make it have a wide application prospect in the micro-nano devices, flexible electronics and biological structures. In this paper, the simulation analysis of the electric fluid movement process was demonstrated, the influence of the electrohydrodynamic jet printing parameters on the jet size was discussed, and the PZT composite suspension was prepared to study the electrohydrodynamic jet printing of PZT thick film micro-scale structures.First, the force analysis of the electrohydrodynamic jet movement process and the numerical analysis of the electrohydrodynamic jet simulation was carried out based on the theory of Leaky-Dielectric. Fluid motion equations, electric field equations and track equations of gas-liquid interface during the formation of electrohydrodynamic jet were deduced. The electrohydrodynamic jet simulation model was built, and the experiments of electrohydrodynamic jet were taken to verify the correctness of the simulation model. Based on this model, the influence of key parameters (voltage, flow rate and height) on jet diameter was analyzed. The results show that flow rate and height have high influence on the jet diameter, while the voltage has less effect on it.Then, the influence of the ball milling conditions on PZT particle size was studied during the preparation of PZT composite suspension. The PZT particle size reduced from 800 nm to 200 nm after 40 hours of ball milling. Moreover, the comparison between the PZT suspension with ball-milling and the PZT suspension with simply mixing was made. The results show that the stratification is obviously decreased and the stability is clearly improved in the suspension with ball-milling. The properties of PZT composite suspension were tested. The results conform with the physical conditions of forming stable "cone-jet" mode. It shows that the PZT composite suspension prepared is suitable for electrohydrodynamic jet printing. Similarly, the electrohydrodynamic jet simulation of PZT composite suspension was carried out to obtain the influence trend of key parameters on jet diameter. Finally, the printing experiments of PZT thick film micro-scale structures were carried out using the electrohydrodynamic jet printing platform and PZT composite suspension. According to the results of the electrohydrodynamic jet simulation analysis, the PZT microstructures with line width variations were produced by changing the height between the nozzle and the substrate, the PZT microstructures with gap variations were produced by adjusting the parameters of X-Y sport platform. The influence of the printing layer number on the PZT thick film cracks was studied in the process of printing PZT thick film. By heat treatment of single printing layer, the organic solvent and residual stress were removed, and the cracks of PZT thick film microstructure were significantly reduced. The piezoelectric and dielectric properties of PZT thick film by electrohydrodynamic jet printing were tested and analyzed. When the polarization voltage was 11 V μm-1, the piezoelectric constant of PZT thick film was 66 p CN-1. When the frequency was 50 Hz, the relative dielectric constant of PZT thick film was 233.