Research On Piezoelectricl Inkjet Jet Characteristics And Residual Oscillation Suppression

In recent years,with the improvement of science and technology,digital printing technology has achieved tremendous development.As one of its important branches,piezoelectric inkjet printing technology is widely used in large-scale inkjet printing,printed electronics,biomedicine,additive manufacturing and many other industrial fields due to its high precision,good stability and strong adaptability.In piezoelectric inkjet,the drive generation of droplets and the state of ink droplet ejection all play an important role in the quality of printing.Therefore,this paper takes the bending piezoelectric drive system as the research object,and deeply researches the influence of the structural parameters of the print head and the drive waveform parameters of the system on the stability of the ink droplet ejection dynamics.The specific content is as follows:(1)Optimize the structural parameters of the print head and analyze its dynamic performance.The numerical model of piezoelectric actuator and print head is established by using COMSOL software.The displacement of the driver and the average velocity of the fluid at the nozzle hole were used as the evaluation criteria to optimize the size of the piezoelectric print head.The best structure size and driving waveform of each part of the piezoelectric print head.(2)A complete piezoelectric inkjet system model was established to study the jet forming process of ink droplets.The established nozzle two-phase flow analysis model is coupled with the piezoelectric print head model,and the characteristics of the ink on the process of droplet formation are studied.Finally,the optimal parameter values of ink properties and nozzle hole shape and size are determined.(3)Aiming at the residual oscillation problem in the system,the driving waveform was designed and optimized,and the limited suppression of the residual oscillation was realized.The established finite element analysis model was used to simulate and analyze the time components of the trapezoidal drive waveform,and the best parameters of each component of the positive polarity single trapezoidal wave were obtained(voltage rise time trise=4 μs,voltage dwell time tdell=8 μs and voltage drop Time tfall=3 μs),and the influence of driving voltage amplitude,voltage dwell time and operating frequency parameters on the ink droplet ejection process is studied;a composite driving waveform that suppresses residual oscillation is designed using the principle of wave superposition.The research results show that the use of This driving waveform can quickly attenuate the residual pressure wave in the print head,shortening the time from 106 μs to 55 μs,improving system efficiency and jetting stability.(4)An ink droplet ejection experiment platform was built to study and analyze the influence of driving voltage amplitude,voltage residence time,and operating frequency on ink droplet ejection characteristics.The simulation results are compared with the experimental results to verify its correctness.