Hybrid high speed machining (HSM): System design and experimental results for grinding/HSM and EDM/HSM

Point grinding and electrical discharge machining (EDM) are detailed on high speed machining centres. A Taguchi design was employed to evaluate operating parameters when point grinding (plunge) nickel-based superalloys with 15 mm diameter electroplated diamond and cubic boron nitride (CBN) wheels using speeds up to 60,000 rpm provided by an ancillary spindle. Material removal of up to 120 cm(3) and roughness values down to 1.2 mum Ra were obtained when machining Inconel 718. A retrofit EDM servo head unit was designed for die sinking and workpiece surface texturing. When texturing 2D and 3D workpieces, surfaces were produced with an Ra of 1-10 mum, depending on operating parameters.