Electrochemical discharge machining of small diameter holes

Electrochemical discharge machining (ECDM) is considered to be a hybrid machining method where material removal is based on two phenomena: electrochemical dissolution of the material and thermal erosion by electrical discharges that occur between the electrodes. Obtaining holes of small diameter in hard materials is one challenge also for this machining method. The paper contains some results obtained by trying to achieve small diameters holes by electrochemical discharge machining using an aqueous solution of sodium silicate as working liquid. Identifying an optimized system for mechanical and electrical equipment was one of the targets of this research. By assuring a relative motion between the electrodes, holes (diameter <1 mm) in cutting steel workpieces were obtained.