Influence of the Composition of WC-Based Cermets on Manufacturability by Wire-EDM

Tungsten carbide (WC) based cermets are widely used in applications where the demand for high-performance materials is essential. These materials are machined either by grinding or wire-EDM. In contrast to grinding, wire-EDM can be highly automated and allows the machining of complex shapes. A recent trend in the development of WC-based cermets is grain size refinement and more narrow grain size distributions of the starting powder material (WC, Co, Ni), which gives a higher hardness and abrasive wear resistance.This paper describes the influence of composition and grain size (coarse …, micron) of WC-based cermets on manufacturability by wire-EDM. It is shown that the cutting rate decreases with increasing WC-grain size, which can be explained mainly by the change in thermal conductivity of the material. Further, the toughness of the base material has an important influence on the bending strength of the EDM-machined samples. Finally, the experiments show that for all investigated materials, the EDM material removal mechanism is mainly melting, while other mechanisms like spalling have not been recognized.