Research On Composite Ultrasonic Energy Transmission Mechanism With Parallel Structure

Ultrasonic technology has been widely used in the advanced manufacture field such as Micro-Electronics, Photo-Electronics and Micro-Electromechanical Systems. It can effectively clear the surface impurities such as the oxide, lower the heating temperature while bonding, reducing the residual stress for the thermal deformation, and improved the bonding strengthen.The composite ultrasonic energy transmission mechanism, which takes advantage of a new composite ultrasonic horn with parallel structure, can effectively produce greater vibration amplitude. This can increase the average density of ultrasonic energy with the vibration frequency unchanged. Meanwhile, different vibration loci distributions are obtained by means of adjust the vibration parameters so that atom proliferation and atomic lattice dislocations happen in larger area, forming uniform bonding between atoms. Therefore, this reduces bonding time and improves bonding efficiency and strength.The structure and design method of the composite ultrasonic energy transmission mechanism with parallel structure are deeply analyzed in this project.First, the principles and formulations of the ultrasonic horn and the piezoelectric ultrasonic transducer, which are the two vital parts of the ultrasonic transmission mechanism, are analyzed. Based on Force and Electric Analog Method, the PZT ultrasonic transducer is analyzed and the formulations for size calculation are obtained according the half-wavelength principle. Based on the Ultrasonic Transfer Matrix Method, the formulations of the composite horn with different cross-section are deduced. Many expression of the acoustic parameters such as the magnification ratio and the frequency equation are obtained. The performance of the horn considering the load effect is also under research.Second, the structure and calculation method of the composite vibration mechanism, including the horn with parallel structure and PZT transducer, are analyzed, and the formulation of the ultrasonic energy average density is deduced. Also, the locus of the end of the composite horn is simulated by software. The transfer matrix coefficients of the composite horn with rectangular cross-section are solved. The lengthen of the horn is optimized according to the relationship of the magnification ratio and the ratio of the horn lengthen. Meanwhile, aiming at the rectangular cross-section, research on the horn considering the load effect is made and a structure for the clamping beam, weakening the horizontal deflection stiffness, is presented to weakening the coupling effects which exists in most parallel structures. By means of the self-locking wedge, the piezoelectric ceramics are effectively preload.Finally, the calculations of the horn lengthen and the PZT ultrasonic transducer are carried out by MATLAB and the whole mechanism is simulated by the ANSYS. Vibration experiments of the mechanism are done to verify the accuracy and precision of the theories.The result of this paper not only provides worthy theory and practical experiment, but also presents a new method to improve the bonding efficiency and strength, finding a new research direction for the bonding equipment.