Effects of process parameters on surface characteristics in micro-EDM performed on ceramic materials

The present research is focused on the application micro-EDM technology on conductive ceramic materials. Nowadays, ceramics are very attractive materials because of their excellent mechanical and thermal properties, but they are extremely difficult to be machined using conventional cutting processes because of their very high hardness. Micro Electro Discharge Machining (micro-EDM) is a non-conventional technology in which the material is removed from the workpiece by the electrical discharges generated in the gap between the workpiece and the tool electrode and it is widely used to realize micro components with complex shapes. Also EDM is limited in machining ceramics because of the high electrical resistivity of these materials. However, even though common ceramic materials cannot be easily machined by EDM, the combination of the basic ceramic materials with other conductive materials may result in a more effective EDM process. In this study three different types of conductive ceramic materials were used as workpiece and a simple micro pocket was chosen as reference shape for the micro-EDM milling. A qualitative analysis of both shape and surface of the pockets was performed using a scanning electron microscope (SEM) while a quantitative surface roughness analysis was executed by means of a measurement system with interferometric sensor. The process performances were evaluated by collecting machining time, tool wear and energy consumption.