Collaborative Research: Unified Three-Dimensional Dynamic Modeling for Drilling and Milling Tool Assemblies (STaRC-3D)

University Of Florida, Gainesville FL

Investigators

Abstract

The research objective of this collaborative research project is to derive and integrate (1) the spectral-Tchebychev technique for modeling drill/endmill dynamics, including the actual fluted geometry, and holders; and (2) the extended receptance coupling substructure analysis technique, for joining tool-holder dynamics to spindle-machine dynamics. The approach to meet this objective includes four primary tasks. First, unified models for three-dimensional dynamics (coupled torsional/axial and bending) of milling and drilling tools, with actual cross-sectional geometry and twist, and holders will be derived using the spectral-Tchebychev technique. Second, the receptance coupling substructure analysis method will be extended to enable the prediction of three-dimensional torsional, axial, and non-axisymmetric bending dynamics. Third, the tool-holder dynamics will be coupled to the spindle-machine dynamics. Fourth, the integrated approach will be verified experimentally. If successful, this work will advance the drilling/milling modeling community by making available a new analytical framework for predicting the coupled torsional/axial and non-axisymmetric bending dynamics of drilling/milling tool-holder-spindle-machine assemblies in an accurate and numerically efficient fashion. This capability does not currently exist and is necessary when modal testing is inconvenient (measurement of many tools in production environments) or impossible (torsional measurements of twist drill-holder-spindle-machine responses or micro-scale tool dynamics). Knowledge of the assembly dynamics will enable a priori selection of optimized operating parameters, which will have immediate application to the aerospace industry (a Boeing 747 airplane has 1.3 million drilled holes) and the US economy (126,000 US companies use 2 milling machine tools and employ 1 million machinists, programmers, and related personnel).