Fabrication of a micro-tool in micro-EDM combined with co-deposited Ni-SiC composites for micro-hole machining

This paper presents an in situ process using a micro-tool in micro-electro-discharge-machining combined with co-deposited Ni-SiC composites to drill and finish micro-holes. During the machining process, a micro-tool is fabricated by wire electro-discharge grinding and electrodeposition. The experimental result shows that the suitable parameters obtained for fabricating micro-tools for Ni-SiC composite coatings are a current density of 7 A dm ^-2, positive ring hole diameter of 5 mm, SiC particle size of 4 νm, SiC particle concentration of 10 g l^-1, rotational speed of 15 rpm and surfactant cetyltrimethylammonium bromide concentration of 150 ppm. When using this method, the micro-tool is provided with a smooth Ni layer, uniform particle distribution and suitable particle adhesion quantity. Then, circular micro-holes are machined in high nickel alloy. Scanning electron microscopy micrographs and atomic force microscopy measurements show that micro-grinding can improve the surface roughness from 1.47 νm Rmax to 0.462 νm Rmax.