Investigation of material removal mechanisms in EDM of composite ceramic materials

Ceramic materials have become important for various industrial applications. Many types have these materials have been developed. However, research and development of ceramic materials, especially suited for electrical discharge machining (EDM), is still limited. This paper presents a detailed investigation of the material removal mechanisms of some commercially available electrical conductive ceramic materials through analysis of the debris and the surface/sub-surface quality. ZrO2-based, Si3N4-based and Al2O3-based ceramic materials, with additions of electrical conductive phases like TiN and TiCN, have been studied. This paper points out that besides the typical EDM material removal mechanisms, such as melting/evaporation and spalling, other mechanisms can occur such as oxidation and dissolution of the base material.