Actuator Structural Optimization And Waveform Design Of Piezoelectric Inkjet Print-head

Inkjet printing technology has become an indispensable technology in the modern industrial manufacturing market due to its unique advantages.However,the inkjet print-head researched and developed independently by Chinese is still relatively few.And most of the core component of the print-head would rely on imports.China is long-term blockade by foreign technology in the field due to lack of the core technology of nozzle manufacturing.This paper mainly studied the structure of the piezoelectric actuator and the waveform design method of piezoelectric inkjet print-head.The following is the main contents of this paper:(1)The related theory of piezoelectric inkjet printing was introduced,including the property and function of the piezoelectric actuator,the vibration mechanism of the piezoelectric actuator,the fluid injection theory,the droplet formation process,the ink characteristic analysis and the mechanism of the actuating waveform acting on the droplet ejection.All of these provided the theoretical basis for the optimization of the structure and size of the piezoelectric actuator and for the design of the actuating waveform.(2)The peak of the displacement of the vibrating plate is used as the main criterion for evaluating the performance of the piezoelectric actuator.The structure and size of each part of the piezoelectric actuator were simulated and optimized,and the displacement amplitude of the vibration plate with different structural parameters was measured by the Laser Doppler Vibrometer to verify the simulation results.Eventually,the structure and size of piezoelectric actuator were determined: the lead zirconate titanate(PZT)thin films were designed as spring structure by the numerical simulation and experimental verification.The width of PZT has three different sizes,which are 90?m,100?m and 110?m,respectively.The thickness of PZT is 1?m.The corresponding width of the SiO2 is 110?m,120?m and 130?m,respectively.The thickness of SiO2 is 0.9?m.The width of the Parylene protective layer is the same as that of SiO2.The thickness of Parylene is 0.7?m.(3)The actuating waveform of the piezoelectric print-head was designed and optimized.Both numerical simulation and experimental results show that the unipolar single-trapezoidal waveform with the parameters tr=3?s,td=16?s,and tf =3?s was the ideal actuating waveform of the inkjet print-head studied in this paper.When the piezoelectric print-head was actuated by the optimized waveform,the print-head was continuous injection with a jetting velocity of5.6 m/s and droplet size of 11 pL.That verified the effectiveness of the waveform design method and the rationality of structure of piezoelectric actuator.