On stability prediction for low radial immersion milling

Stability boundaries for milling are predicted by the zeroth-order approximation (ZOA) and the semi-discretization (SD) methods. For high radial immersions, the methods predict similar stability boundaries. As radial immersion is decreased, the disagreement between the predictions of the two methods grows considerably. The most prominent difference is an additional type of instability predicted only by the SD method. The experiments confirm the predictions of the SD method. Three different types of tool motion are observed: periodic chatter-free, quasiperiodic chatter, and periodic chatter motion. Tool displacements recorded during each of the three motion types are analyzed.