Micro Electro Discharge Machining of Nonconductive Ceramic: The Issue of Spalling

  • Abstract
  • Keywords
  • References
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  • Abstract

    Nonconductive ceramic materials are used in many engineering applications such as car brake, turbine blade, and hip-bone replacement because of its high dimensional accuracy, corrosion and wear resistant, and biocompatibility. These materials are usually processed with diamond grinding and limited laser applications such as cutting, drilling and scribing. Specific shapes and profiles are still difficult and costly to machine using these processes. Electrical discharge machining (EDM), extensively used for various shapes and profiles on conductive materials having minimum electrical conductivity of 0.10 S.cm-1. It is not directly applicable on nonconductive ceramic materials due to its very low electrical conductivity (<10-10 S.cm-1). However, recently EDM is used on nonconductive materials with the aid of assisting electrode to initiate the spark between conductive tool electrode and nonconductive workpiece. The available material removal models of EDM are based on single spark erosion with uniform melting and vaporization of workpiece materials. However, in EDM of nonconductive ceramics, material removal is not uniform because of random spalling due to alternating thermal stress. In addition, it is difficult to create single spark erosion on a nonconductive ceramic workpiece as initial sparks are occurred between tool electrode and assisting electrode attached to workpiece. This paper presents the empirical factor for the estimation of spalling along with melting and vaporization through experimental study. Model of material removal rate as a function of capacitance and voltage are developed in micromachining of nonconductive zirconium oxide (ZrO2) using (R-C) pulse type micro-EDM. The single spark erosion volume is derived from the fundamental principle of melting and vaporization. An empirical correction factor is introduced to compensate random spalling and multi-spark erosion effect.



  • Keywords

    Assisting electrode; Carbonic dielectric fluid; Material removal; Micro-EDM; Nonconductive ceramic; Pyrolytic carbon; Spalling.

  • References

      [1] Chevalier, J., & Gremillard, L. (2009). Ceramics for medical applications: a picture for the next 20 years. Journal of the European Ceramic Society, 29 (7), 1245-1255.

      [2] Bonny, K., De Baets, P., Vleugels, J., Salehi, A., Van der Biest, O., Lauwers, B., & Liu, W. (2009). EDM machinability and fractional behavior of ZrO2-WC composites. International Journal of Advanced Manufacturing Technology, 41 (11-12), 1085-1093.

      [3] Hosel, T., Muller, C., & Reinecke, H. (2011). Spark erosive structuring of electrically nonconductive zirconia with an assisting electrode. CIRP Journal of Manufacturing Science and Technology, 4 (4), 357-361.

      [4] Hosel, T., Cvancara, P., Ganz, T., Muller, C., & Reinecke, H. (2011a). Characterization of high aspect ratio non-conductive ceramic microstructures made by spark erosion. Microsystem Technologies, 17 (2), 313-318.

      [5] Patel, K. M., Pandey, P. M., & Rao, P. V. (2010). Optimisation of process parameters for multi-performance characteristics in EDM of Al2O3 ceramic composite. International Journal of Advanced Manufacturing Technology, 47(9-12), 1137-1147.

      [6] Mohri, N., Fukuzawa, Y., Tani, T., Saito, N., & Furutani, K. (1996). Assisting electrode method for machining insulating ceramics. CIRP Annals-Manufacturing Technology, 45 (1), 201-204.

      [7] Banu, A., Ali, M. Y., & Rahman, M. A. (2014). Micro-electro discharge machining of non-conductive zirconia ceramic: investigation of MRR and recast layer hardness. International Journal of Advanced Manufacturing Technology, 75 (1-4), 257-267.

      [8] Chen, Y. F., Lin, Y. J., Lin, Y. C., Chen, S. L., & Hsu, L. R. (2010). Optimization of electrodischarge machining parameters on ZrO2 ceramic using the Taguchi method. Journal of Engineering Manufacture, 224 (2), 195-205.

      [9] Sabur, A., Moudood, A., Ali, M. Y., & Maleque, M. A. (2013). Investigation of surface roughness in micro-electro discharge machining of nonconductive ZrO2 for MEMS application. IOP Conference Series: Materials Science and Engineering, 53 (1), 012090.

      [10] Schubert, A., Zeidler, H., Wolf, N., & Hackert, M. (2011). Micro electro discharge machining of electrically nonconductive ceramics. AIP Conference Proceedings, 1353 (1), 1303-1308.

      [11] Schubert, A., Ziedler, H., Kuhn, R, & Hackert-Oschatzchen, M. (2015). Microelectrical discharge machining: a suitable process for machining ceramics. Journal of Ceramics, 2015.

      [12] Liu, Y. H., Ji, R. J., Li, X. P., Yu, L. L., & Zhang, H. F. (2008). Electric discharge milling of insulating ceramics. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 222 (2), 361-366.

      [13] Izquierdo, B., Sanchez, J. A., Plaza, S., Pombo, I., & Ortega, N. (2009). A numerical model of the EDM process considering the effect of multiple discharges. International Journal of Machine Tools and Manufacture, 49 (3), 220-229.

      [14] Salonitis, K., Stournaras, A., Stavropoulos, P., & Chryssolouris, G. (2009). Thermal modelling of the material removal rate and surface roughness for die-sinking EDM. International Journal of Advanced Manufacturing Technology, 40(3-4), 316-323.

      [15] Liu, Y. H., Yu, L. L., Xu, Y. L., Ji, R. J., & Li, Q. Y. (2009). Numerical simulation of single pulse discharge machining insulating Al2O3 ceramic. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 223 (1), 55-62.

      [16] Wong, Y. S., Rahman, M., Lim, H. S., Han, H., & Ravi, N. (2003). Investgation of micro-EDM material removal characteristics using single RC-pulse discharges. Journal of Materials Processing Technology, 140 (1), 303-307.

      [17] Zahiruddin, M. & Kunieda, M. (2012). Comparison of energy and removal efficencies between micro and macro EDM. CIRP Annals-Manufacturing Technology, 61 (1), 187-190.

      [18] Kiran, M. P. K. & Joshi, S. S. (2007). Modeling of surface roughness and the role of debris in micro-EDM. Journal of Manufacturing Science and Engineering, 129 (2), 265-273.

      [19] Alexander, C. K., Sadiku, M. N., & Sadiku, M. (2007). Fundamentals of Electric Circuits: McGraw-Hill Higher Education.

      [20] Liao, Y. S., Chang, T. Y., & Chuang, T. J. (2008). An on-line monitoring system for a micro electrical discharge machining (micro-EDM) process. Journal of Micromechanics and Microengineering, 18 (3), 035009.

      [21] Schubert, A., Zeidler, H., Hackert-Oschätzchen, M., Schneider, J., & Hahn, M. (2013). Enhancing micro-EDM using ultrasonic vibration and approaches for machining of nonconducting ceramics. Journal of Mechanical Engineering, 59(3), 156-164.

      [22] Aligiri, E., Yeo, S. H., & Tan, P. C. (2010). A new tool wear compensation method based on real-time estimation of material removal volume in micro-EDM. Journal of Materials Processing Technology, 210(15), 2292-2303.

      [23] Dhanik, S., & Joshi, S. S. (2005). Modeling of a single resistance capacitance pulse discharge in micro-electro discharge machining. Journal of Manufacturing Science and Engineering, 127 (4), 759-767.

      [24] Ji, R., Liu, Y., Zhang, Y., Wang, F., Cai, B., & Fu, X. (2012). Single discharge machining insulating Al2O3 ceramic with high instantaneous pulse energy in kerosene. Materials and Manufacturing Processes, 27 (6), 676-682.

      [25] Trueman, C. & Huddleston, J. (2000). Material removal by spalling during EDM of ceramics. Journal of the European Ceramic Society, 20 (10), 1629-1635.

      [26] Abbas, N. M., Solomon, D. G., & Bahari, M. F. (2007). A review on current research trends in electrical discharge machining (EDM). International Journal of Machine Tools and Manufacture, 47(7), 1214-1228.




Article ID: 17297
DOI: 10.14419/ijet.v7i3.24.17297

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