Abstract: Aiming at the problem of difficult machining on the deep blind small hole of the aluminum alloy body of the cylinder combination valve,electrochemcial drilling method was applied.In order to improve the machining stability of electrochemical drilling of deep blind small holes in aluminum alloy,the distributions regularity of electric field and flow field in the machining gap under different electrode feed rates were simulated and analyzed. In order to study the effects of initial gap,electrode feed rate and electrode rotation on electrochemical drilling,the tube electrode with an inner diameter of 0.6 mm and an outer diameter of 1.0 mm was used for machining aluminum alloy 6061. Simulation and experimental results show that a too large or too small electrode feed rate is not conducive to the machining stability of deep blind small hole drilling. When the electrode feed rate is greater than 1.4 mm/min,the hole bottom is easy to form a protrusion,and when the electrode feed rate is less than 1.0 mm/min,the hole bottom is easy to form pits. The initial gap of 0.3 mm is benificial for the orifice morphology,and the electrode rotation facilitates the discharge of product and heat,thus improving processing accuracy. A hole array with the center distance of 2.46 mm and the averaged diameter of 1.28 mm was fabricated by using optimal parameters,and a deep blind small hole with the averaged diameter of 1.29 mm and the depth of 50 mm was obtained.

Key words: cylinder combination valve, electrochemcial drilling, deep blind small hole drilling, machining stability, machining gap, electrode rotation