Luận văn Simulation And Fabrication Of Piezoelectric Mems Inkjet Print Head

Microelectromechanical systems (MEMS) have played an increasingly important role in sensor and actuator applications. And its key contribution is that it has enabled the integration of multi-components (i.e., electronics, mechanics, fluidics and etc) on a single chip and their integration has positive effects upon performance, reliability and cost. Compared to conventional electrostatic, thermal or magnetic actuating schemes, piezoelectric MEMS inkjet has the advantages of lower power consumption, lower voltage operation and relatively larger driving force. Based on the primary design and fabrication of piezoelectric MEMS inkjet (1stversion-InkjetVer1) done in our STD Lab, the computer simulation and validation of inkjet have been investigated, and then the 2nd version (InkjetVer2) with the modified nozzle shape was fabricated and characterized. In details, firstly the simulation of piezoelectric MEMS inkjet with the electro-mechanical-fluid interaction has been performed. In order to verify the simulation results, a fabrication and characterization ofactuator part consisting of PZT-based actuating membrane and ink chamber was carried out. These treatments are to determine how much “dynamic force”, in terms of membrane’s maximum displacement, maximum force and driving frequency, can be produced by the actuator membrane. Secondly, a simulation of microdroplet generation in inkjet has also been done. This work gives an understanding about the droplet generation process, and the effects of driving characteristics, fluid properties and geometrical parameters on droplet generation. Especially, this simulation helps to predict how much “dynamic force” is required to generate mirodroplets. The combination of both results (i.e., how much “dynamic force” produced and required) gives an effective guideline in designing inkjet structure. Thirdly, in the experimental work, the fabrication of InkjetVer2was carried out based on MEMS techniques. And then its electrical, mechanical characteristics as well as possibility of ink ejection were also tested.