Optimization of non-uniform allowance process of thin-walled parts based on eigenvalue sensitivity

Abstract

In the numerical control machining of thin-walled parts, the quality and stiffness of the thin-walled structure will change continuously, due to the removal of the material. The cutting characteristics will also change significantly. One of the chatters in cutting process is a serious problem. Presently, the main solutions are to achieve steady cutting from the process route, the external process stiffness, the clamping scheme, the optimization of the dynamic parameters, and the adoption of new processes. In light of the chatter problem of thin-walled parts, it is based on the structural stiffness and modal finite element analysis of thin-walled workpiece. The allowance distribution state of thin-walled workpiece is determined and optimized in semi-finishing machining, based on eigenvalue sensitivity analysis method. The goal is to minimize the structural allowance, and the non-uniform allowance design method is achieved by optimizing the thickness of the grid allowance in the premise of ensuring its thin-walled stiffness and other modal characteristics. The goal of improving the process its own rigidity of the thin-walled parts is realized. Finally, the comparison of the experimental results between the uniform allowance process distribution and the non-uniform allowance process scheme is made. The results indicate that the non-uniform allowance of optimization program based on eigenvalue sensitivity can improve both the stiffness and the main modal frequency of the thin-walled structure, which can guarantee the stability of the cutting process.