Micromachining Of Ceramics Bearing Components For Turbomachinery Applications

This paper addresses the production by micro Electrical Discharge Machining (EDM) milling of ceramics thrust bearing surfaces to be inserted in an air bearing unit for high speed (up to 500 krpm) turbomachinery applications. A ZrO2-TiN electrical conductive ceramic composite is here selected as structural material in order to fulfil the functional requirements of the component and allow its accurate and flexible machining via EDM. EDM experiments are firstly conducted towards the definition of suitable machining conditions. The components are realized by applying a layer-by layer milling strategy. The surface quality and geometrical accuracy are finally evaluated; the surface roughness obtained is 0.23 mm and the overall accuracy is within 2 mm.