Evaluation of surface profiles of sloped pockets machined on Si3N4-TiN via micro-EDM milling

In this paper, the study of tridimensional 45°-sloped pockets realized in Si3N4-TiN ceramic composite machined via micro-EDM milling is reported. The experimental results obtained by measurements performed directly on the micro-EDM milling machine show that most of the errors of the inclined surface manufacturing are detected in the first part of the erosion process. Our analysis shows that the surface imperfections are related to the energy used in the process, the frequency of electrical touches done to detect tool wear and feature depth error, the initial values of the parameter set to compensate tool wear and the layer thickness set to implement the layer-by-layer strategy. Morphological measurements, performed using Axio CSM 700 confocal microscope, have confirmed that the surfaces of the inclined walls suffer of some defects on the top of the pockets. However, the surface profiles are quite good and no step-like trends have been detected.