Experimental Research On Processing Parameters Optimization In Two-dimensional Ultrasonic Polishing Without Abrasives

Surface polishing machining of metal material, whether it is the traditional grinding, polishing or non-traditional finishing methods, such as ultrasonic lapping, magnetic grinding polishing, ultrasonic EDM polishing, are the material removing process which can only reduce the value of surface roughness, can't improve the surface hardness. Polishing without abrasives is a non-material-removing process that may significantly reduce the value of surface roughness and improve surface hardness. But the parts may be easily scratched, peeled and damaged. Two-dimensional ultrasonic machining is new processing technology in recent years, and has been proved to achieve better quality than single vibration mode machining, so that is applied in polishing without abrasives in order to obtain better processing quality.The processing mechanism and technology of two-dimensional ultrasonic polishing without abrasives are studied in this thesis. Firstly, longitudinal bending vibration device was developed, and the formation condition of two-dimensional vibration is analyzed in theory. The dynamic analysis of acoustic systems were analyzed to study the transient response and steady-state response of acoustic system under the exciting of cosine of the displacement, which proved that elliptical vibration may be achieved by the designed acoustic system. Then processing mechanism of two-dimensional ultrasonic polishing without abrasives was analyzed. The influencing order of parameters on surface roughness and surface hardness was presented, the optimum polishing parameters of ultrasonic vibration polishing were put forward by the orthogonal test, and the experimental formula of the surface roughness and hardness were given using multiple linear regression method. Lastly, the micro-structure and three-dimensional topography of the machined surface were obtained by microscope and the white light interferometer, the processing mechanism of two-dimensional ultrasonic polishing without abrasives were analyzed further.The research results are helpful to reveal the processing mechanism of two-dimensional ultrasonic polishing without abrasives, develop the new technology of the metal parts finishing, and further promote the application of ultrasonic polishing without abrasives.