| The bar whose length-to-diameter ratio is more than20is called slender bar. It is widely used in the industry of aerospace, automobile, construction machinery and military. Because of its low radial rigidity, it is easily bending under cutting force when it is turned causing drum-shaped deformation. In order to solve the problem that slender bar is difficult to turn, using aluminum alloy6061as research subject, the new technique ultrasonic vibration is brought in and flexure deformation mathematical model of ultrasonic vibration cutting slender bar is built; Based on modifying the common lathe, ultrasonic vibration turning system is built and the relative experiment is conducted and the influence of cutting parameter on the flexure deformation of slender bar is achieved and its empirical formula is established.Flexure deformation mathematical model of slender bar under cutting force is established. By using the method of orthogonal experiment the empirical formula of radial turning force in ultrasonic vibration turning slender bar is established. Combining the two formulas the flexure deformation mathematical model of slender bar using ultrasonic vibration turning is achieved. The influence of cutting parameter as well as length-to-diameter ratio on flexure deformation of slender bar is studied and numerical simulation is conducted. Meanwhile by using finite element analysis software the result of numerical simulation is tested and verified.In order to establish ultrasonic vibration turning system, how to choose lathe, ultrasonic generator, cutting tool is analyzed. Energy transducer as well as a kind of amplitude transformer horn with multi sections is designed. Model analysis as well as Harmonic response analysis of the designed horn is conducted. The influence of tool nose’s stretch length, tool clearance, tool material and tool shape on resonance frequency of horn is studied. A kind of special blade adapter for ultrasonic vibration turning is designed. The rigidity of whole ultrasonic vibration system is analyzed using finite element analysis method getting the result that its rigidity can satisfy the demand. Ultrasonic vibration experiment system is established and tested in order to achieve its optimum working condition.The experiment of ultrasonic vibration turning slender bar is conducted and the influence of cutting parameter and length-to-diameter on flexure deformation of slender bar in the position of tool nose is studied. The difference between common turning and ultrasonic vibration turning in the aspect of deformation in the position of tool nose, surface roughness, and chip appearance is contradicted. The empirical formula of maximum flexure deformation in the position of tool nose and cutting parameter is achieved and regression tested. The result of experiment shows that ultrasonic vibration turning can remarkably decrease flexure deformation and surface roughness. |
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