Optimization And Vibration Characteristic Anslysis For Major Components In Delicated Machining System

The thin-walled workpiece has been widely used in many fields includingaeronautics and astronautics, chemical engineering, nuclear energy, etc. And thedynamic characteristic of machining system of the delicated CNC machine tools usedfor machining thin-walled circular cylindrical shell has a significant effect on surfacequality and machining efficiency of the workpiece. In order to improve themachinability of thin-walled circular cylindrical shell, the major components ofmachining system (boring bar, tail-stock and external tool post) are researched bothfunctionally and structurally. It is of great value to study the vibration analysis andstructural optimization theoretically and practically.Based upon the pro-existing machining system and the analysis for dynamiccharacteristic experiment of delicated machining system, the common boring bar isreplaced by the damping boring bar and the dimension parameters of tail-stock andexternal tool post are optimized. Main research contents are: the parameters ofvibration absorbers are tuned using the energy method, a new tuning methodologyproposed in this paper; the cutting head of boring bar is designed and the method ofengineering application is discussed; the three major components of machiningsystem are modeled and analyzed using the software of3D modeling and FEA; pro/eand ansys are integrated by isight, which is used for dimension parametersoptimization of boring bar, tail-stock and external tool post.According to the vibration analysis and structural optimization, the conclusionsare drawn as follows:(1) The mathematical model of damping boring bar is established and theanalytical solutions are given. The energy equation of absorbers is deduced using theprincipal of energy consumption of viscous damping. The optimal parameters ofabsorbers are fitted aiming at maximum energy consumption at largest range offrequency.(2) Comparing the energy method to the traditional methods, the results ofdifferent optimal parameters are given corresponding to different design criterion. And the flowchart of energy consumption used for tuning parameters is drawn. Theworking process of vibration system is calculated numerically by Matlab, and theresults are verified by adams Multi-body dynamic software.(3) Research on the selection of vibration-block’s material, elastic-element’sform and material, damper’s materials, etc. The cutting head of boring bar is designedand the application of absorbers to the practical engineering is discussed. The boringbar, tail-stock and external tool post are modeled and analyzed. The majorcharacteristics of every vibration mode are discussed as well as the main reason andconresponding improved solutions.(4) The basic steps of isight software integrating pro/e and ansys are given andthe major components of machining system of delicated CNC machine tools areoptimized structurally, respectively.