Fluid-solid Coupling Dynamic Simulation Analysis And Experimental Study Of Piezoelectric Stacks Driven Jetting Dispenser With A Diamond Amplifying Structure

Piezoelectric Stack driven jetting dispenser is widely used in microelectronics packaging.In the dispensing process of jetting dispenser,there is fluid-solid coupling effect between the needle and the glue,and this fluid-solid coupling effect is decisive to the dispensing process of jetting dispenser.Only by mastering the fluid-solid coupling law between the needle and the glue,can we fully know the performance of the jetting dispenser and judge under what conditions the jetting dispenser can accomplish the dispensing process successfully.This is of great significance to the design and improvement of jetting dispenser,and can also provide guidance for experimental research and practical use of jetting dispenser.However,in the available literature,the fluid-solid effect between the needle and the glue in the dispensing process is not fully considered in the study of jetting dispenser.To solve this problem,based on a Piezoelectric Stacks Driven Jetting Dispenser with a Diamond Amplifying Structure,the fluid-solid coupling process between the needle and the glue in the dispensing process of the jetting dispenser was explored in this paper,and a fluid-solid coupling dynamic simulation analysis method of the jetting dispenser was proposed,which was verified by experiments.Simulation analysis of fluid-solid coupling dynamics of the dispenser: Firstly,the ADAMS-Simulink co-simulation model of the mechanical system of the jetting dispenser and FLUENT simulation model of the fluid system of the jetting dispenser are established.There is no existing interface for fluid-solid coupling dynamics analysis between the ADAMS-Simulink co-simulation model and FLUENT fluid simulation model,so the coupling force between the needle and glue needs to be solved as a link to combine the two parts of the simulation.Secondly,the coupling force between the needle and glue was studied.The FLUENT simulation was used to determine the influencing factors of the coupling force between the needle and glue,which include the speed of the needle,the relative position between needle and nozzle and the viscosity of glue.The interpolation function of coupling force is defined based on FLUENT simulation results.Thirdly,by combining the ADAMS-Simulink co-simulation model of the mechanical system of the jetting dispenser and FLUENT simulation model of the fluid system of the jetting dispenser,the fluid-solid coupling dynamics simulation model of jetting dispenser was established.Based on the model,the influence of different initial conditions on jetting dispenser was analyzed.Finally,the dispensing results of the jetting dispenser at 200 Hz frequency under different initial conditions was summarized,and two necessary conditions for the successful dispensing were put forward: Firstly,only when the mass of the droplet is larger than a certain value,can the jetting dispenser dispense successfully.This certain value changes with the change of the viscosity of the glue,and for the glue with a viscosity of 0.5Pa.s,the mass of the droplet must be larger than 8.283 ug.Secondly,only when the viscosity of glue is larger than 0.02 Pa.s and lesser than 1.5Pa.s,can the jetting dispenser dispense successfully.Experimental study of the jetting dispenser: the experimental platform of the jetting dispenser was built.Firstly,the displacement curve,velocity curve of the needle and the mass of the droplets were measured at different duty cycle,different inlet pressure of the glue and different viscosity of the glue when the jetting dispenser was applied at a frequency of 200 Hz.The experimental results show that the influence of changing inlet pressure of the glue on the fluid-solid coupling dynamic response of the mechanical system of the jetting dispenser can be ignored,and the influence of changing duty cycle and the viscosity of glue on the fluid-solid coupling dynamic response of the mechanical system of the jetting dispenser is significant.The mass of the droplets increases with the increase of the inlet pressure of the glue,and decreases with the increase of the duty cycle and the viscosity of the glue,which is consistent with the results obtained from the fluid-solid coupling dynamic analysis of the jetting dispenser.Secondly,the initial conditions of the jetting dispenser in the experiment and simulation are consistent.The displacement curve and velocity curve of the needle are measured respectively through the simulation and experiment,and the mass of the droplets are recorded.The displacement curves of needle obtained from experiment and simulation are almost identical.Furthermore,the comparison between the experimental and simulated velocity curves of the needle shows that they almost coincide,indicating that the fluid-solid coupling dynamic simulation model of the jetting dispenser can accurately simulate the actual dynamic response of the mechanical system of the jetting dispenser.Finally,the minimum mass of droplets with a viscosity of 0.5022 Pa.s was measured under experimental conditions.It was 16.52 ug,which was larger than 8.283 ug.The viscosity range of the glue in which the jetting dispenser can dispense successfully is 0.1154 Pa.s≤μ≤0.9732 Pa.s,which was within the range of0.02 Pa.s≤μ≤1.5Pa.s.