Experimental Research Of Piezoelectric Electrostatic Micro Liquid Point Injection System

The research and development of micro liquid point injection has a history of many years.With the rapid development of computer,communication and consumer electronic products to miniaturization,integration and portability,more and more micro liquid point injection processes are involved in the electronic manufacturing process,and the requirements for micro liquid point injection technology in the aspects of miniaturity,precision,uniformity and reliability are also higher and higher A variety of forms and categories of micro liquid point injection technology and equipment have been formed.For micro liquid point injection technology,the technology does not need z-axis movement,does not contact with the workpiece,can dispensing in a very small gap,has the advantages of high dispensing accuracy,fast speed,good consistency and so on,and has achieved rapid development,becoming one of the most important high-tech and equipment in the field of electronic manufacturing in recent years.The piezoelectric electrostatic micro liquid point injection system uses the circular piezoelectric vibrator as the driving element,through the regular vibration of the piezoelectric vibrator to change the volume of the control chamber,so that the fluid pressure in the chamber changes,and then the liquid morphology at the nozzle changes,forming the micro liquid point on-demand injection.With piezoelectric vibrator as the driving element,it has the advantages of rapid deformation,high precision and small volume,which can realize the precise control of micro liquid point injection process.This paper focuses on the simulation analysis and experimental research of the piezoelectric electrostatic micro droplet injection technology.Firstly,the piezoelectric control module of the piezoelectric electrostatic micro droplet injection system is described,the performance of the piezoelectric vibrator is analyzed theoretically andsimulated,and the optimal height of the chamber is determined through the test.Based on the theory of hydrodynamics and electrodynamics,the process of piezoelectric electrostatic micro liquid point injection is analyzed,and the mathematical model of piezoelectric electrostatic micro liquid point injection is established.Based on the mathematical model,the injection process of the micro liquid point is simulated and analyzed by using COMSOL software in the way of multi physical field coupling.The influence rules between the diameter of the micro liquid point and the amplitude,frequency and electrostatic field voltage of the piezoelectric vibrator are obtained by analyzing the data,which provides the theoretical basis and basis for the design of the piezoelectric electrostatic micro liquid point injection system.Finally,the effects of the amplitude,frequency and electrostatic field voltage of the piezoelectric vibrator on the diameter of the microdroplet are studied by orthogonal experiment.High viscosity liquid methyl silicone oil was chosen as the injection object.The piezoelectric vibrator driven by pulse signal was used in the experiment of micro liquid injection.The test results show that the pressure at the inlet is 80 Pa,the voltage at the nozzle is 5kV,the output displacement of piezoelectric vibrator is 0.03 mm,and the output frequency is 200 Hz.The diameter of the injection point is the smallest,and the average diameter of the micro liquid point produced by the injection is 53.5mm.