Abstract:

At present, the research of machining stability mostly focuses on the stability of different machining methods or cutting conditions. Maximum depth of cut within stable zone is proposed as optimal cutting parameters, but the incorporation of stability and optimization model is ignored. A new cutting parameter optimization model under constrain of milling stability is proposed. The objective function is constructed with material removal rate (MRR) and TL (tool life) to realize comprehensive optimization of efficiency and cost with quality control. Through the analysis of zero order analytical (ZOA) solution of chatter stability in milling, the influence of cutting force model, tool point frequency response function (FRF), and cutting parameters to stability zone are discussed. The change of stability lobe is studied which led to the conclusion that maximum depth of cut within stable zone dose not guarantee maximum MRR. Genetic algorithm is introduced to realize global optimization of cutting parameters under constrain of stability and machine limitations. To solve the difficulty of weight setting in multi-objective optimization, MRR and TL expectations are used to make the optimization model quantitative and adjustable. Based on impact test and cutting test on machining center VMC850, optimization trials are conducted using different sets of parameters. Results show that the cutting parameter is in the stable zone and optimization direction is manipulable.

Key words: cutting parameter optimization, genetic algorithm, objective function, machining stabilit