Linear improvement of the machining stability lobes and application in milling process prediction

Abstract

Aiming at an in-depth understanding of the machine tool-cutting tool dynamics and its integrated contribution to the machining process stability, this paper presents an improved linear approach for milling process stability prediction. Via modal decoupling and reconstruction, the dominant modes of the machine tool-cutting tool combination are reallocated and chatter criteria are redefined. Using optimally identified pole-pairs and residues, the experimentally measured frequency response function (FRF) at the cutting edge is renormalized, to achieve an improved calibration standard for calculation of the stability lobes. In addition, the cross-term modal coupling effects are introduced into the calculation of the orientated transfer function (OTF), which gives a better theoretical integrity and higher prediction precision. Using these theoretical improvements, software is developed and experimentally validated. This includes automatic trimming of stability lobes, acoustic validation of chatter vibration occurrence, etc. The effectiveness and applicability of the method developed are also discussed.