Optimal milling modes identification of a jet-engine blade using time-domain technique

Abstract

This paper considers a method of determining a chatter-free milling mode using time-domain milling dynamics simulation. The simulation is using a depth-buffer algorithm, an adaptive finite element model of the in-process workpiece, and a phenomenological model of cutting forces. The frequency characteristics of the in-process workpiece are obtained from the experimental modal analysis. The simulation analyzes the in-process workpiece vibration and actual cutting forces for the specified machining trajectory, as well as part surface quality after machining. The chatter-free milling mode is determined using a milling map produced by a multiple simulation for different spindle speed values. The milling map specifies regions where chatter may occur during milling and indicates the variation of the optimal spindle speed along the machining trajectory. The proposed method is used to determine a chatter-free milling mode for the finish milling of a jet-engine compressor blade. The blade is machined under the chatter-free milling mode, and it has good surface finish quality without chatter marks, whereas a blade machined under constant spindle speed contains chatter marks. The method can be used to engineer milling processes for other thin-walled workpieces with complex geometry and low stiffness.