Design and Fabrication of an Aerodynamic Micro-Air Journal Bearing Using Micro-Wire Electrical Discharge Machining

Abstract:

This paper proposed a removal analysis and a contouring strategy of accurate micro-WEDM processing for an aerodynamic micro-air journal bearing for micro-gas turbine engine. It is designed based on aerodynamic theory and can be self-acting by the compressed air pressure. The rotor is stably rotated in a relatively low speed which is below one hundred thousand revolutions per minute, and is much lower than other references. The extended and trimmed tool path is adopted in this paper, and the cusp at the corner of the micro-air journal bearing is obtained by this method which is better than the common arc tool path. The inner and outer diameter of the micro-air journal bearing with a satisfactory shape and good surface quality is 1.068mm and 1.165mm, respectively. The minimum radius at the bottom of wedged-structure is 15.9μm. The kerf of the blanking is 43μm, and the machining discharge gap is 18μm under this machining conditions. The MRR calculated by experimental data is 0.00144mm²/min.

• Periodical: Key Engineering Materials (Volumes 562-565)
• Pages: 8-12
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.562-565.8
• Online since: July 2013
• Authors: Yu Kui Wang, Zhao Qi Zeng, Zhen Long Wang, Xiao Long He
• Keywords: Micro-Air Journal Bearing, Micro-Wire Electrical Discharge Machining, Tool Path

References

[1] A.H. Epstein, S.D. Senturia, O.Al-Midani, et al. Micro-heat engines, gas turbines, and rocket engines-The MIT microengine project. Proceedings of the 28th AIAA Fluid Dynamics Conference. (1997) June 29; pp.97-1773.

DOI: 10.2514/6.1997-1773

[2] A.H. Epstein. Millimeter-scale, MEMS gas turbine engines. Proc. ASME Turbo Expo 2003, Power for Land, Sea, and Air. (2003), GT-2003-38866.

DOI: 10.1115/gt2003-38866

[3] S. Kang, J.P. Johnston, T. Arima, et al. Micro-scale radial-flow compressor impeller made of silicon nitride-manufacturing and performance. Proc. ASME Turbo Expo 2003, Power for Land, Sea, and Air, (2003), GT2003-38933.

DOI: 10.1115/gt2003-38933

[4] K. Isomura, S. Tanaka, M. Murayama, et al. Development of micro-turbo charger and micro-combustor as feasibility studies of three-dimensional gas turbine at micro-scale. Pro. ASME Turbo Expo 2003, Power for Land, Sea, and Air. (2003), GT2003-38151.

DOI: 10.1115/gt2003-38151

[5] A.H. Epstein. Millimeter-scale, micro-electro-mechanical systems gas turbine engines, ASME Journal of Engineering for Gas Turbines and Power, Vol. 126 (2004), pp.205-226.

DOI: 10.1115/1.1739245

[6] Micro power generation based on micro gas turbines: a challenge, mstnews, No.4/05, August (2005), pp.37-39.

[7] Jun Qu, Albert J. Shih, Ronald O. Scattergood. Development of the Cylindrical Wire Electrical Discharge Machining Process, Part 1: Concept, Design, and Material Removal Rate. Journal of Manufacturing Science and Engineering, Vol.124, August (2002), pp.702-707.

DOI: 10.1115/1.1475321