Research On Microcantilever Machined By Micro Ultrasonic Machining And Its Mechanical Properties

Microcantilever is a common structure in Micro Electro Mechanical System(MEMS),which is widely used in micro modulator,micro brake,micro energy collector,micro mechanical switch and other micro devices and equipment.Traditional microcantilever beam processing mostly adopts silicon micromachining technology,which has high production cost,complicated process,environmental pollution caused by corrosive agents used in the preparation process and difficult control of corrosion precision.Ultra-thin glass is widely used in indoor buildings,wearable devices,smart phones,tablet computers,energy storage and other fields due to its light weight,high light transmittance,good photoelectric performance,corrosion resistance and other advantages,but it is rarely reported as a substrate material for microcantilevers.In order to solve the problem of preparing ultra-thin glass microcantilever,a micro ultrasonic machining system based on equivalent impedance control strategy of ultrasonic vibration system is constructed in this thesis.Ultra-thin glass microcantilever is prepared by micro ultrasonic machining method,and PBZ ferroelectric thin film is prepared by using ultra-thin glass microcantilever as substrate.The mechanical properties of ultra-thin glass microcantilever are studied by using inverse piezoelectric effect.The innovative research work completed in this thesis mainly includes:(1)The load characteristics of micro ultrasonic machining power supply are analyzed,and a programmable constant current ultrasonic power supply for micro ultrasonic machining based on DSP with power of 100W and output current peak-to-peak value of 0?1200m A is independently developed.The performance test results show that the power supply can meet the requirements of microcantilever micro ultrasonic machining in terms of frequency tracking,power adjustment,current output and impedance matching.(2)The relationship between equivalent impedance of ultrasonic vibration system,machining force and machining gap is analyzed.Combined with the automatic feed adjustment characteristic of ultrasonic machining,an automatic feed control strategy for micro ultrasonic machining based on equivalent impedance of ultrasonic vibration system is proposed,and the basic principle of the control strategy is expounded.On this basis,an automatic feed adjustment system based on the control strategy is designed and implemented.The test results show that the automatic feed adjustment system has fast response speed and high processing stability.(3)The load impedance characteristics of the ultrasonic vibration system are studied,and the ultrasonic vibration system(piezoelectric transducer,ultrasonic horn and tool head)for microcantilever ultrasonic machining is designed and manufactured.The modal of the ultrasonic horn is analyzed by ANSYS software.The test results show that the deviation between the resonant frequency of the assembled ultrasonic vibration system and the design simulation results is less than0.5%.(4)Based on the above research results,an ultra-thin glass microcantilever micro ultrasonic machining system is constructed,and an ultra-thin glass microcantilever array with an aspect size of less than 1000?m and a minimum thickness of 180?m is prepared.The impedance control law of micro ultrasonic machining system based on equivalent impedance control strategy is studied through micro ultrasonic micro-hole machining test and ultra-thin glass microcantilever preparation test.(5)A process route for preparing piezoelectric films on ultra-thin glass microcantilever substrates by sol-gel method is proposed.The electrical performance test results of the piezoelectric films show that the PBZ-La Ni O₃ structure has an ideal hysteresis loop.The effects of the thickness of the microcantilever substrate and the thickness of the piezoelectric film on the natural frequency of the microcantilever are simulated by ANSYS software.The variation trend of the simulation results is basically consistent with the test results based on inverse piezoelectric effect,which provides experimental basis for the wide application of ultra-thin glass piezoelectric microcantilever in MEMS field.