Experimental Investigation of Wire Electrical Discharge Machining of NdFeB Permanent Magnets with an RC-Type Machine
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This paper focuses on wire electrical discharge machining (WEDM) of devices made from commercially available sintered neodymium-iron-boron (NdFeB) rare-earth magnets that have been magnetized before machining. We conduct an experimental study to quantify the effects of the voltage and capacitance of an RC-type WEDM machine, as well as the magnet polarity, on slicing rate, mean kerf, and variation in kerf. We find that voltage and capacitance affect slicing rate, that voltage affects mean kerf, that no parameters tested affect the variation in kerf, and that the polarity of the magnet being machined does not affect the machining process. Linear regression is used to fit simple predictive models to the data with good agreement. Further analysis is performed to characterize the loss in permanent magnetization on the surface of the magnet due to heating during the machining process, and it is found that the outer layer of approximately 35 μm in depth is demagnetized when using the highest voltage and capacitance values tested.
Keywordsdemagnetization EDM kerf magnetization slicing rate
This material is based upon work supported by the National Science Foundation under Grant Nos. 0952718 and 0654414.
- 4.L. Li, D. Wang, Z.W. Niu, and J.H. Zhang, Investigation of Material Removal Mechanism in EDM of Sintered NdFeB Permanent Magnet, Key Eng. Mater., 2007, 334–335, p 937–940Google Scholar
- 5.L. Li, R. Gou, and G. Yuan, A New Erosion Protection Machining Method for Sintered NdFeB Permanent Magnet, J. Aust. Ceram. Soc., 2008, 44(1), p 31–33Google Scholar
- 8.L. Li, Z.W. Niu, and G. Yuan, Effect of Ultrasonic Vibration of Tool on Electrical Discharge Machining of Sintered NdFeB Magnet, Prog. Mach. Technol., 2009, 407–408, p 628–631Google Scholar
- 9.P.J. Ross, Taguchi Techniques for Quality Engineering: Loss Function, Orthogonal Experiments, Parameter and Tolerance Design, McGraw-Hill, New York, 1988Google Scholar
- 11.J.M.D. Coey, Rare-Earth Iron Permanent Magnets, Oxford University Press, Oxford, 1996Google Scholar
- 15.C. Orino, D. Rakwal, J.D. Jorgensen, and E. Bamberg, Development of a precision, low-cost, small footprint wire electron discharge machine (WEDM), Proc. ASPE Conf., 2006, p 239–242.Google Scholar
- 18.D. Rakwal, and E. Bamberg, Using Taguchi Methods to Optimize the Slicing Rate and Surface Roughness for Wire Electrical Discharge Machining of p-type Germanium, Proc. 15th Int Symp Electromachining (ISEM XV), Pittsburg, PA, 2007, p 127–132Google Scholar
- 19.J. Greer, Wire Electrical Discharge Machining of Helical Devices from Permanent Magnets. Master’s Thesis, Department of Mechanical Engineering, University of Utah, Salt Lake City, Utah, 2011Google Scholar
- 21.R.C. O’Handley, Modern Magnetic Materials: Principles and Applications, Wiley, New York, 2000Google Scholar
- 23.L. Li, Z. Niu, F. Yin, and Y. Liu, Surface Integrity of Sintered NdFeB Permanent Magnet After EDM, Adv. Mater. Res., 2012, 503–504, p 27–30Google Scholar