Electrochemical machining of a narrow slit by cathodic compound feeding

Abstract

Narrow slits are widely used in aerospace, instrument and meter, and heat-transfer equipment. Electrochemical machining (ECM) has the advantage of being free of tool wear, heat-affected zone, and machining deformation, and is suitable for high-precision machining of narrow slits. However, conventional cathodic continuous linear feeding causes serious stray removal at the narrow slit side wall and results in poor forming precision. This paper presents a new compound feeding method with vibration superimposed on a continuous linear feeding method and investigates the electrochemical machining of a narrow slit using this method. Its influence on narrow slit formation based on the numerical analysis of an electric field is studied as well. The results indicate that compound feeding is superior to linear feeding in terms of less stray removal and a smaller slit width. Comparative experiments of the compound and linear feeding with voltage pulses are also conducted based on a self-developed ECM system, with vibration frequencies from 0 to 50 Hz and vibration amplitudes from 0 to 2 mm. The results demonstrate that not only the average slit width and side-wall slope are smaller, but also the localization of the narrow slit electrochemical machining can be significantly enhanced by compound feeding.