| Thin-walled cylindrical shell is one of the typical hard-machining work pieces, easy to vibrate. The vibration and cutting stability are closely linked. Based on the dynamic characteristics of machine tools, on the one hand, the optimization of cutting parameters is studied, on the other hand, after the LMS experimental modal analysis and finite element analysis, structure of machining system is optimized. The main contents are as follows:(1) Considering the thin-walled cylindrical shell as flexible body and the tool as flexible body, the dynamic model of cutting thin-walled cylindrical shell is established. The mathematical model of spindle speed with respect to regenerative critical cutting width is derived. Furthermore, factors impacting cutting stability are analyzed.(2) The various parameters of the cutting system are identified through the use of experiments. According to the Euler - Bernoulli beam theory and the free vibration decay curve, the equivalent mass, the equivalent stiffness and equivalent damping of the cutter are obtained; The first-order natural frequency of the work piece is obtained by LMS modal analysis; Cutting force equation is obtained by the cutting test and multiple linear regression fitting, resulting in dynamic cutting stiffness.(3) The mathematical model is established, with cutting efficiency as the main goal, with cutting force, cutting power, surface roughness and stability as the constraints. Optimal cutting parameters are obtained by the application of particle swarm optimization. And the use of experiment is used to verify the effectiveness of the optimal cutting parameters.(4) By ANSYS, the static analysis and modal analysis are carried on stock tail. Then, PROE software and ANSYS software are integrated by ISIGHT. Key design variables are obtained by design of experiment. Finally, optimization is carried. |
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