Investigating Dynamics of Machine Tool Spindles under Operational Conditions

Chatter is one of the major problems in machining and can be avoided by stability diagrams which are generated using frequency response functions (FRF) at the tool tip. During cutting operations, discrepancies between the stability diagrams obtained by using FRFs measured at the idle state and the actual stability of the process are frequently observed. These deviations can be attributed to the changes of machine dynamics under cutting conditions. In this paper, the effects of the cutting process on the spindle dynamics are investigated both experimentally and analytically. The variations in the spindle dynamics are attributed to the changes in the bearing parameters. FRFs under cutting conditions are obtained through the input-output relations of the cutting forces and the vibration response which are measured simultaneously. Experimentally and analytically obtained FRFs are then used in the identification of the bearing parameters under cutting conditions. Thus, bearing properties obtained at idle and cutting conditions are compared and variations in their values are obtained.

[1]  J. Bendat,et al.  Random Data: Analysis and Measurement Procedures , 1971 .

[2]  Victor Songmene,et al.  Estimation of machine-tool dynamic parameters during machining operation through operational modal analysis , 2009 .

[3]  Julius S. Bendat,et al.  Engineering Applications of Correlation and Spectral Analysis , 1980 .

[4]  V. T. Portman.  Stiffness and Damping in Mechanical Design , 2000 .

[5]  J. R. BELL,et al.  Rotational vibration measurements using laser doppler vibrometry: comprehensive theory and practical application , 2000 .

[6]  Erhan Budak,et al.  Selection of design and operational parameters in spindle–holder–tool assemblies for maximum chatter stability by using a new analytical model , 2007 .

[7]  Erhan Budak,et al.  Analytical modeling of spindle-tool dynamics on machine tools using Timoshenko beam model and receptance coupling for the prediction of tool point FRF , 2006 .

[8]  Kihong Shin,et al.  Fundamentals of Signal Processing for Sound and Vibration Engineers , 2008 .

[9]  Yusuf Altintas,et al.  Analytical Prediction of Chatter Stability in Milling—Part I: General Formulation , 1998 .

[10]  Matti Rantatalo,et al.  Laser vibrometry measurements of an optically smooth rotating spindle , 2007 .

[11]  Pascal Ray,et al.  Stability-based spindle speed control during flexible workpiece high-speed milling , 2008 .

[12]  G. L. Xiong,et al.  Study of the gyroscopic effect of the spindle on the stability characteristics of the milling system , 2003 .

[13]  Yusuf Altintas,et al.  Virtual Design and Optimization of Machine Tool Spindles , 2005 .

[14]  B. J. Stone.  The State of the Art in the Measurement of the Stiffness and Damping of Rolling Element Bearings , 1982 .

[15]  Mohammad R. Movahhedy,et al.  Prediction of chatter in high speed milling including gyroscopic effects , 2006 .

[16]  H. Nevzat Özgüven,et al.  Structural modifications using frequency response functions , 1990 .

[17]  Ioannis Minis,et al.  Analysis of Linear and Nonlinear Chatter in Milling , 1990 .

[18]  Steve Rothberg,et al.  On the application of laser vibrometry to translational and rotational vibration measurements on rotating shafts , 2004 .

[19]  Eugene I. Rivin,et al.  Stiffness and Damping in Mechanical Design , 1999 .

[20]  Yusuf Altintas,et al.  Analytical Prediction of Stability Lobes in Milling , 1995 .

[21]  Hongqi Li,et al.  Analysis of bearing configuration effects on high speed spindles using an integrated dynamic thermo-mechanical spindle model , 2004 .

[22]  Chi-Wei Lin,et al.  An integrated thermo-mechanical-dynamic model to characterize motorized machine tool spindles during very high speed rotation , 2003 .

[23]  Steve Rothberg,et al.  Laser vibrometry: Pseudo-vibrations , 1989 .

[24]  Steve Rothberg,et al.  Speckle noise reduction in laser vibrometry: experimental and numerical optimisation , 1996, Other Conferences.

[25]  Steve Rothberg,et al.  LASER VIBROMETERS AND CONTACTING TRANSDUCERS, TARGET ROTATION AND SIX DEGREE-OF-FREEDOM VIBRATION: WHAT DO WE REALLY MEASURE? , 2000 .

[26]  Per Gren,et al.  Measurement of milling tool vibrations during cutting using laser vibrometry , 2008 .