Mechanism clarification and realization of scanning electrochemical machining of titanium alloys

Abstract

Electrochemical machining (ECM) is a noncontact removal machining method based on electrolytic action, can be effectively used to remove metallic materials, regardless of the material hardness. Due to its excellent features, ECM is usually used to realize the shape generation of difficult-to-cut metallic materials. However, when processing certain typical difficult-to-cut materials, such as titanium alloy and tungsten carbide, an oxide film is formed on the workpiece surface, which hinders the further dissolution of the material. Passivation due to oxide film formation generally occurs under a low current density. During the generation of a complicated shape through small tool electrode scanning, the low-current-density area around the peripheral area of the tool eventually covers the complete machining area. Consequently, the passivation becomes highly intense, and a suitable shape may not be generated. To solve this problem and realize the shape generation of titanium alloys in scanning ECM, the characteristics of the oxide film and its influence on material dissolution when using a suction tool were investigated based on current distribution calculations and machining experiments. A model for the scanning ECM of titanium alloys and guidelines for designing the scanning tool and determining machining conditions were proposed. The effectiveness of the proposed model and guidelines were validated through experiments with a suction tool.