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 0.00144mm 2 /min.