Abstract: Ni-based superalloy GH4169 is a material frequently used for aeroengine blades. To obtain the characteristics of the ηω-i curve of GH4169 precisely, a new method called the cathode speed control method is adopted to control the machining gap so that the machining process can reach an equilibrium state quickly. Electrochemical machining (ECM) experiments are conducted by means of this method and the ηω-i curve is drawn after a series of calculation. The curve shows that when current density i is below 6 A/cm2, the ηω value approaches 0; and when i is above 50 A/cm2, the ηω keeps constant at the point of 1.28 mm3/(A·min). In the final part of this article, two cathodes are designed respectively in light of a certain aeroengine blade and their different ηω-i curves drawn respectively by the speed control method and the unchanged speed method. Then, contrastive experiments between them are carried out. The results show that the cathode designed according to the ηω-i curve by the speed control method achieves better duplication accuracy, and the overall blade accuracy is increased by 0.03 mm. Therefore, the characteristics of the ηω-i curve obtained by this new method are more satisfactory.

Key words: speed control, electrochemical machining, ηω-i curve, current density, blade, cathode design