On Overlapping the Pulses on Cumulative Microjets Stage at Ultrasonically Aided Electrical Discharge Machining

Abstract:

The paper deals with a solution to increase the machining rate at electrical discharge machining aided by ultrasonics (EDM+US), i.e. the overlapping the voltage pulses provided by EDM generator on the cumulative microjets stage (CMS), which occurs at every final of an ultrasonic period by collective implosion of the gas bubbles from the working gap. This overlapping moves the limit of the removed material by a discharge from the boiling isothermal (at classic EDM) to melting isothermal (at EDM+US) as it is emphasized by the results of finite element analysis. The preliminary experimental data analyzed in the paper are obtained in case of random overlapping at ultrasonic frequency of 20 kHz. They demonstrate an increase of machining rate with more than 300% at EDM+US in comparison with classic EDM in the same working conditions.

• Periodical: Applied Mechanics and Materials (Volume 834)
• Pages: 126-131
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.834.126
• Online since: April 2016
• Authors: Daniel Ghiculescu*, Niculae Marinescu, Ovidiu Alupei
• Keywords: Cumulative Microjets Stage, Electrical Discharge Machining, Ultrasonics

References

[1] B. C. Khatri, P. Rathod and J. B Valaki, Ultrasonic vibration–assisted electric discharge machining: A research review, Proceedings of the Institution of Mechanical Engineers, Part B, Journal of Engineering Manufacture, March (2015) 1-12.

DOI: 10.1177/0954405415573061

[2] S. Z. Chavoshi, X. Luo, Hybrid micro-machining processes: A review, Precision Engineering, 41 (2015) 1-23.

DOI: 10.1016/j.precisioneng.2015.03.001

[3] T. Endo, T. Tsujimoto, K. Mitsui, Study of vibration-assisted micro-EDM, The effect of vibration on machining time and stability of discharge, Precision Engineering 32(4) (2008) 269–277.

DOI: 10.1016/j.precisioneng.2007.09.003

[4] Z.Y. Yu, Y. Zhang, J. Li, J. Luan, F. Zhao, D. Guo, High aspect ratio microhole drilling aided with ultrasonic vibration and planetary movement of electrode by micro-EDM, CIRP Annals: Manufacturing Technology, 58 (2009) 213–216.

DOI: 10.1016/j.cirp.2009.03.111

[5] K. Suzuki, T. Takada, Z. R. Zhou, T. Okamichi, M. Iwai, S. Ninomiya, Effects of Ultrasonic Vibrations Given to an Electrode on the EDM Performance in Processing PCD, Advanced Materials Research, 565 (2012) 394-399.

DOI: 10.4028/www.scientific.net/amr.565.394

[6] M.T. Shervani-Tabar, K. Maghsoudi, M.R. Shabgard, Effects of simultaneous ultrasonic vibration of the tool and the workpiece in ultrasonic assisted EDM, Int. J. Comput. Meth. Eng. Sci. Mech., 14(1) (2013) 1–9.

DOI: 10.1080/15502287.2012.698696

[7] V.S.R. Murthi, P.K. Philip, Pulse train analysis in ultrasonic assisted EDM, International Journal of Machine Tools and Manufacture, 27(4) (1987) 469–477.

DOI: 10.1016/s0890-6955(87)80019-6

[8] H. -P. Schulze, G. Wollenberg, R. Herms, K. Mecke, Gas bubble morphology in small working gaps at spark erosion, 2004 Annual report Conference on Electrical Insulation and Dielectric Phenomena, Boulder, Colorado, USA, 16-20, October (2004).

DOI: 10.1109/ceidp.2004.1364305

[9] D. Ghiculescu, N.I. Marinescu, G. Varga, S. Nanu, FEM study of thermal front dynamics at micro-electrical discharge machining aided and not aided by ultrasonics, Nonconventional Technologies Review, Vol. 18(3) (2014) 43-48.