A TWO-DIAMETER HELICAL ENDMILL BEAM MODEL FOR TOOL TIP DYNAMICS PREDICTION WITH APPLICATION TO MILLING

The aim of this dissertation is to describe the dynamic response of helical endmill geometries to enable the use of receptance coupling substructure analysis (RCSA) to predict the tool tip vibration response of arbitrary tool-holder-spindle-machine combinations. The tool tip vibration response, or receptance, is a key input for milling stability prediction. Currently, a measurement is required to determine the tool tip receptance for each tool-holder-spindle-machine combination, which may not be possible in production environments. In the RCSA approach, the spindle receptances are measured once and archived, while the tool and holder are modeled. Tool tip receptances are predicted by analytically coupling the tool and holder models, described as equivalent diameter Timoshenko beams, to the archived spindle receptances. In this study, a two-diameter Timoshenko beam model approach is derived and applied to predict the dynamic response of the fluted portion of the endmill geometry.