Design Of An Eccentric Cone Ultrasonic Elliptical Vibration Cutting Tool And Its Performance In Pure Iron Cutting

Ultrasonic elliptical vibration machining is an advanced cutting technology,especially suitable for cutting soft,sticky,hard and other difficult-to-cut materials.The working principle of the cutting technology is to create an elliptical vibration trajectory of the tool at the end of the ultrasonic elliptical vibration cutting device.The plane of this trajectory is formed by the cutting direction and the depth of cut direction.In ultrasonic elliptical vibration cutting,the tool intermittently cuts into and out of the workpiece,while the upward pull of the tool along the elliptical trajectory improves the forward inclination of the tool,which avoids the friction between the side of the tool and the machined surface of the workpiece and facilitates the vertical vibration movement of the tool to pull the chips away from the workpiece,thus significantly reducing the cutting force and cutting temperature.In order to be able to realize the advantages of ultrasonic elliptical vibration cutting and to obtain ultrasonic elliptical vibration tools with more compact and simple structures,the thesis proposed a single-excitation eccentric cone ultrasonic elliptical vibration tool on the basis of mechanical vibration theory,and carried out basic research on related cutting processing.The dimensions of the eccentric cone ultrasonic elliptical vibration tool were obtained by combining theoretical calculation and finite element analysis(FEA);Impedance analysis and vibration characteristics analysis were performed on the tool to verify the rationality of the tool design;The cutting performance of the eccentric cone ultrasonic elliptical vibration tool was verified by cutting experiments on pure iron DT8 workpiece.The main research work completed as follows:(1)The theoretical analysis of single-excitation elliptical vibration trajectory was carried out to obtain the formation conditions of elliptical vibration trajectory,and the simulation analysis of single-excitation vibration by using Matlab software proved that eccentric cone structure horn single-excitation vibration can synthesize elliptical vibration trajectory.(2)The design of the overall structure of the eccentric cone ultrasonic elliptical vibration cutting device was completed.The design process of the tool was described,and the preliminary dimensional parameters of the tool were obtained by theoretical calculations.Based on the theoretical calculation results,the modal analysis,harmonic response analysis and display dynamics analysis of the eccentric cone ultrasonic elliptical vibration tool were carried out.Based on the theoretical calculation and finite element analysis,the prototype of the ultrasonic elliptical vibrating tool with eccentric cone was developed,and we designed a tool shell.(3)The impedance characteristic analysis of the eccentric cone ultrasonic elliptical vibration tool was carried out,and the resonant frequency F_s=28.04k Hz and other parameters were obtained,as well as the trajectory curves of the conductance circle and G-B with frequency.The displacement characteristic analysis of the eccentric cone ultrasonic elliptical vibration tool was carried out,and the amplitude of the tool in the Z direction(longitudinal vibration)was 6.2μm,and the amplitude in the Y direction(bending vibration)was 4.9μm,and the phase difference was about 1.34π.(4)The cutting performance of this eccentric cone ultrasonic elliptical vibration tool was verified by cutting experiments on pure iron DT8.The tool can make fundamental changes in the microscopic shape of the workpiece surface and effectively reduce the cutting force,cutting temperature,roughness and tool wear.Based on the above experiments,further cutting experiments on pure iron DT8 workpiece were conducted to verify the effects of corner radius,rounded cutting edge radius,wiper and cutting fluid on cutting force,cutting temperature and roughness in ultrasonic elliptical vibration cutting.