Robust optimization of machining parameters based on edge theorem

Traditional mathematic models for predicting milling stability assume that dynamic parameters of machine tools remain constant. However, these parameters such as natural frequencies and cutting force coefficients vary under operational state, reducing accuracies of the chatter prediction and related machining parameters optimization. In this study, the edge theorem and the zero exclusion condition are used to extend the traditional stability model for considering the effects of the uncertain parameters. Thus, robust combinations of the spindle speed and axial cutting depth are predicted. They are the inputs of the optimization model to obtain the maximum material remove rate MMR based on the particle swarm optimization method. The proposed machining parameters optimization method was applied on a real vertical machining center, and its effectiveness was validated by the chatter tests.