The Theory Analysis And Research On Workpiece Roundness Erorr Of Ultrasonic Vibration Turning

Roundness accuracy, one of the most common shape accuracy,proposes accuracy requirements on cylindrical,conical,cylindrical and bore.How to ensure accuracy, reducing roundness error is the classic puzzle in traditional turning field. For the process of turning is mainly impacted by cutting force, cutting heat and stiffness change, ultrasonic vibration turning is brought in and the roundness error mathematical model is established.Based on the common lathe, ultrasonic vibration turning system is built.The influence of cutting parameter on roundness error is achieved and its empirical formula is established.According to the positional relationship,the mathematical model of cutting force is set up with certain assumptions,system stiffness is reasonable calculated, the theoretical relationship model between roundness error and cutting parameter under ultrasonic vibration turning is deduced.During the numerical simulation, compared with the common turning,the influence of cutting parameter on roundness error is studied.In order to establish experiment system,selection and design of ultrasonic generator, transducer, horn and special turret is done.The rigidity of whole ultrasonic vibration system is analyzed,the result shows that rigidity of the system can meet the demand. Ultrasonic vibration experiment system established is tested to achieve optimum working condition.The single factor contrast experiments of ultrasonic vibration and common turning are conducted and the influence of cutting parameter and amplitude is studied. The differences between two turning ways in the aspect of roundness curve,surface roughness and chip appearance are contradicted. The empirical formula of roundness error and cutting parameter is achieved by orthogonal experiment.The good-of-fit test, regression equation test and regression coefficient test for the empirical formula of roundness error are conducted.The result of experiment shows that ultrasonic vibration turning can remarkably decrease roundness error under the experimental conditions and the established empirical formula is accurate and reliable,which owes practical significance.