1. Experimental investigations on micro-EDM milling of niobium carbide-nickel based cermet using statistical and empirical techniques.
- Author
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Ye, Long, Saxena, Krishna Kumar, Huang, Shuigen, Qian, Jun, Vleugels, Jef, and Reynaerts, Dominiek
- Abstract
Niobium Carbide (NbC) based cermet is a relatively less explored wear resistant material which has potential applications in moulds for ceramic injection moulding as well as cutting tool inserts. The NbC-Ni based cermets exhibit similar hardness as WC-Co cemented carbide but show better wear resistance and chemical stability against iron or steel. The demand for Ni bonded NbC cermets is forecasted to increase due to the rising cost of Co in conventional WC-Co cemented carbides. This poses additional challenges for existing mechanical micromachining processes such as frequent tool failure, higher tool wear and poor surface quality. Therefore, electrically conductive sintered NbC matrix cermets with a Ni binder have been developed which makes it suitable to machine them using electro discharge machining (EDM) and electrochemical machining (ECM) operations. This work presents experimental investigations using micro-EDM milling operation on NbC-Ni workpieces. A combination of empirical and statistical studies is employed to determine the suitable processing window for this material. The empirical study involves microstructural analysis and surface topography characterization using scanning electron microscopy (SEM) and confocal microscopy, respectively. The microstructural features such as micro-cracks, micro-cavities, micro-voids and micro-globules are identified and related to the major material removal mode of melting/vaporization. The statistical study involves parameter optimization and process monitoring. Material removal rate (MRR) of 0.091 mm
3 /min and tool wear rate (TWR) of 0.048 mm3 /min can be achieved to its optimality and tracking the change in sparks frequency, shorts frequency and feed-rate enables to detect the suddenly accumulated debris. In this way, this holistic approach has been demonstrated to achieve an improvement in understanding and optimizing the machining process for novel NbC matrix cermet using micro-EDM technology. [ABSTRACT FROM AUTHOR]- Published
- 2022
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