Dynamic Model Of Mirror Cutting About Thin-walled Cylinder Workpiece And Research On Servo Support

Thin-walled cylinder workpiece is widely used in aerospace and other fields.However,due to the poor rigidity and high elastic-plasticity of thin-walled cylinder workpiece,it is very easy to generate vibration in the process of machining,which not only seriously affects the surface quality and dimensional accuracy of thin-walled cylinder workpiece,but also influences the precision of machine tool and the life of tool.Therefore,it is of great theoretical and engineering significance to research the mechanism of cutting vibration of thin-walled cylinder workpiece and put forward effective measures to suppress the cutting vibration.The machining residual wall thickness of thin-walled cylinder workpiece studied in this paper is only 1mm,which is obviously more difficult than that of ordinary thin plate and thin-walled curved workpiece.Aiming at the machining problem of thin-walled cylinder workpiece,a method of mirror cutting method with servo support is proposed.In mirror cutting,the radial cutting force of the inner boring tool and the outer turning tool can partially offset,which has achieved the purpose of suppressing vibration.The servo support can move synchronously with the cutting process and provide support force in real time.At the same time,the support area can cover the outer surface of the whole thin-walled cylinder workpiece,ensuring the machining surface of the whole thin-walled cylinder workpiece to reach a relatively uniform surface quality and dimensional accuracy.The main contents are as follows:1.Dynamic analysis and modeling of thin-walled cylinder workpiece and boring bar are carried out respectively by using Kirchhoff-Love shell theory and Euler-Bernoulli beam theory.Considering the dynamic change of cutting depth in mirror machining,a dynamic model of mirror machining of thin-walled cylinder workpiece is established.Based on the modal superposition method,the dynamic simulation of the cutting vibration of thin-walled cylinder workpiece is carried out,and the accuracy of the dynamic model is verified by comparing with the experimental signal.2.The dynamic model of mirror machining of thin-walled cylinder workpiece with servo support is established.The influence of the support position and support parameters on the vibration suppression effect of the servo support is analyzed by using contour diagram.Select the appropriate parameters and carry out the dynamic simulation of the cutting vibration of the thin-walled cylinder workpiece based on the modal superposition method.The accuracy of the dynamic model is verified by experiments.Finally,by comparing the changes of cutting vibration of thin-walled cylinder workpiece with or without servo support,the actual effect of servo support is verified.3.Optimization model of the servo support parameters is established,and determine the optimization objective.Through DOE experiment,the influence of the parameters of the servo support on the optimization objective is analyzed.The intelligent algorithm integrated in Isight is applied to combine with Matlab software to carry out multi-objective optimization of servo support parameters to obtain the best combination of parameters.By means of unit impulse function,unit step function and simulated cutting,the superiority of the optimal parameter set are proved.4.Semi-active control servo support head is designed.Ansys Electronics software is applied to carry out electromagnetic simulation on the magnetic circuit of the servo support head.The final structural parameters that meet the requirements of magnetic circuit are determined by the comprehensive comparison of magnetic field line distribution diagram and magnetic induction intensity cloud map.