Research On Dynamic Modeling And Printing Process Of A Piezoelectric Micro-droplet Jetting 3D Printing Head

In recent years,piezoelectric microdroplet jetting 3D printing technology has made significant progress in cutting-edge fields of science and technology due to its advantages of high resolution,high speed,and high precision.However,this technology still faces challenges in predicting the droplet jetting process and controlling printing quality.This paper focuses on the industrial-grade micro-droplet inkjet 3D printing head and elaborates in detail the working principle of the piezoelectric micro-droplet inkjet printing head.Specifically,the Newton’s laws of motion and the N-S equations are used to describe the changes in the ink chamber of the printing head.Based on the theory of pressure wave propagation,the micro-droplet formation process is explained.In addition,the spreading process of droplets is theoretically analyzed from the perspective of energy conservation,and the penetration process of droplets is analyzed from the perspective of porous media and mass transfer.These theories provide a theoretical basis for establishing a finite element model and conducting simulation calculations in Chapter 3 of this paper.This paper establishes a fully coupled micro-droplet ejection dynamic model of the printing head,which combines the physical quantities of the piezoelectric effect,fluid-solid coupling,and gas-liquid two-phase flow subsystems into an integrated model to improve the accuracy of the computational results and facilitate the exploration of the influencing factors of micro-droplet ejection process.Meanwhile,the spreading model of droplets and the infiltration model of droplets are established,and the simulation analysis is carried out to obtain the volume fraction image of the fluid at different times during the printing process,the pressure image inside the printing head,the ejection velocity image,the droplet spreading image,and the droplet infiltration image.The model’s correctness is validated by performing experiments and comparing the simulation results with experimental results.This paper presents an in-depth study of the bending deformation of the piezoelectric actuator and droplet ejection process based on a fully coupled model.The effects of factors such as driving voltage amplitude,voltage waveform,ink properties,and nozzle diameter on droplet formation and ejection are investigated,and their underlying reasons are theoretically analyzed.Additionally,the droplet spreading process is thoroughly studied based on the droplet spreading model,and the effects of droplet properties,falling velocity,and substrate friction on spreading are analyzed.Furthermore,the droplet infiltration process and the effects of porosity and ink viscosity on infiltration are investigated based on the droplet infiltration model.The obtained conclusions provide valuable references for the development of piezoelectric droplet printing technology.