Numerical Simulation Of Thermally Assisted Electrohydrodynamic Jet And Experimental Research

Electrohydrodynamic jet(E-Jet)printing is a printing manufacturing technology based on the electric hydrodynamic effect,which has prominent advantages in the printing manufacturing of micro-nano three-dimensional structure and has become a hot research topic for domestic and foreign experts.It has been widely used in micro-nano sensors,tissue engineering,new-generation electronic products and other fields.However,due to the limitation of the surface morphology and internal interface of 3D structure built layer by layer by traditional printing method,the quality of 3D structures is reduced.In addition,there are many factors affecting the results of E-Jet printing,and it is difficult to summarize the influence rules of these factors in the experiment,resulting in long experiment cycle and difficulties.Therefore,the simulation research of a thermal field assisted E-Jet printing was carried out in this paper,according to the thermal field assisted E-Jet printing mechanism,the thermal field auxiliary device was designed,through the simulation analysis of the key parameters on the printing results,the thermal field assisted E-Jet printing experiment was carried out,and the micron scale 3D structures were printed.Firstly,the force analysis of thermal field auxiliary E-Jet printing was carried out based on the theory of "Leaky-Dielectric",and the influence of each force on the jet was analyzed.The mechanism of thermal field assisted E-Jet printing was explored,and a printingsolidification-forming printing process was proposed.According to this,a thermally assisted E-Jet printing equipment was built.From the aspects of material selection and structural design,the thermal field assisted E-Jet printing device was developed.With the electric power dragging to form stable ink jet,the precise control of the substrate temperature and the in-situ rapid curing molding function were realized,the auxiliary function of the thermal field of E-Jet printing was realized.Then,the numerical simulation of thermal field assisted E-Jet printing was carried out.Fluid motion equations,thermal field equations,electric field equations and interface tracking equations were deduced using Navier-stokes equation and Maxwell stress method.Through the steps of establishing geometric model,setting boundary conditions,meshing and solving calculation,the simulation model was built by using COMSOL software.The effects of different key parameters on jet diameter were analyzed,and the results show that the size of the printing structure is inversely proportional to the voltage and temperature,and directly proportional to the flow rate.Finally,the experiment was carried out.By comparing the simulation results with the experimental results,the correctness of the simulation model was verified.The control system of thermal field assisted E-Jet printing equipment was developed,and the cooperative control of each function module was realized.The current measurement device was designed to ensure the stability of the printing process.The results of simulation analysis were used to guide the printing experiment,the key printing parameters were optimized,and the thermal field assisted E-Jet printing experiment was carried out.The needle with an inner diameter of 50 um was used.At last,using PZT sol as the printing material,the 3D PZT microstructure with a height of 2mm and a diameter of 25 um was fabricated.