I-016

Modeling of the Holding Force in an Electromagnetic

Authors: Alejandro Felix, Shreyes N. Melkote*, Yoichi Matsumoto**
Affiliation: *The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology
**The Timken Company

Abstract
This paper addresses the modeling and prediction of the holding force in an electromagnetic chuck used in precision machining. First, an analytic model termed the magnetic circuit model was developed and compared with experimental holding force data. It was found that this model, although simple in form, was limited in its ability to accurately predict the holding force over the entire range of conditions investigated. The discrepancies in the model were attributed to its inability to accurately model the leakage flux and non-uniform distribution of the magnetic flux. A three-dimensional finite element model was then developed to overcome these limitations. Predictions with this model were found to be in better agreement with experiments, yielding prediction errors within 25% for most cases. Furthermore, the finite element model also provided an explanation for the observed decrease in the measured holding force at current values beyond a certain threshold.

Shreyes N. Melkote
The George W. Woodruff School of Mechanical Engineering
Georgia Institute of Technology
Atlanta, Georgia 30332-0405
shreyes.melkote@me.gatech.edu