ROTATING TOOL POINT FREQUENCY RESPONSE PREDICTION USING RCSA

Abstract

This article describes the prediction of rotating tool point frequency response functions using receptance coupling substructure analysis (RCSA). In this approach, the at-speed spindle-machine dynamics are identified by impact tests of a rotating cylindrical standard artifact. After removing the portion of the artifact beyond the holder flange in simulation, models of arbitrary tool-holder combinations are coupled to the spindle response to predict the speed-dependent tool point frequency response. Given this information, process dynamics predictions for spindles that exhibit dynamic changes with rotating speed are made possible without detailed knowledge of the spindle geometry, assembly tolerances, etc. Experimental results and comparisons with prediction are provided.

Keywords:

• Dynamic
• Milling
• Receptance
• Spindle
• Stability
• Variance

ACKNOWLEDGMENTS

The authors gratefully acknowledge support of this research by the National Science Foundation (Grant No. DMI-0238019). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of this agency.

Notes

¹Frequency response functions are also referred to as receptances. A direct receptance is obtained when the excitation and measurement locations coincide. A cross-receptance is obtained when they do not.

²The outer diameter for section I accounts for the reduced second area moment of inertia due to the fluted portion of the endmill, Duncan (2006).