Titanium alloy TC4 is widely used as the material of aero-engine blade, which is a typical difficult-to-process material. Electrochemical machining (ECM) is the preferred processing technology for titanium alloy TC4 because it does not depend on the strength and hardness of the material itself, high processing efficiency, and good surface quality. In this paper, the flow field characteristics and experiments of ECM of titanium alloy TC4 twisted blades are studied. According to the characteristics of the blade itself, the lateral flow tangential inlet flow field and the corresponding complex fixture and tool electrode are designed. The theoretical and geometric models of the flow field simulation are established, and the finite element simulation analysis of the flow field is carried out. The results show that the electrolyte flow rate in the new flow field is high and evenly distributed, and there is no shortage of liquid and vortex defects, which can meet the needs of ECM. The experiments of ECM parameters optimization are carried out, and it is found that pulse frequency and duty cycle have a key effect on the surface quality of titanium alloy TC4 blade. The experimental results show that the machining process is very stable under the new flow field mode and optimized machining parameters. The surface of the titanium alloy TC4 blade is bright and without defects. The surface roughness of the concave and the convex are Ra 0.44 μm and Ra 0.47 μm, respectively. The profile accuracy of concave and convex were -0.008 ~ +0.057 mm and -0.002 ~ +0.059 mm, respectively.

Improvements in aero-engine performance have made the structures of the aero-engine components increasingly complex. To better adapt to the processing requirements of narrow twisted channels such as an integral shrouded blisk, this study proposes an innovative method of electrochemical cutting in which a flexible tube electrode is controlled by online deformation during processing. In this study, the processing principle of electrochemical cutting with a flexible electrode for controlled online deformation (FECC) was revealed for the first time. The online deformation process of flexible electrodes and the machining process of profiles were analysed in depth, and the corresponding theoretical models were established. Conventional electrochemical machining (ECM) is a multi-physical field-coupled process involving electric and flow fields. In FECC, classical mechanics are introduced into the tool cathode, which must be loaded at all times during the machining process. Therefore, in this study, before and after the deformation of the flexible electrode, a corresponding simulation study was conducted to understand the influence of the online deformation of the flexible electrode on the flow and electric fields. The feasibility of flexible electrodes for online deformation and the validity of the theoretical model were verified by deformation measurements and in situ observation experiments. Finally, the method was successfully applied to the machining of nickel-based high-temperature alloys, and different specifications of flexible electrodes were used to complete the machining of the corresponding complex profiles, thereby verifying the feasibility and versatility of the method. The method proposed in this study breaks the tradition of using a non-deformable cathode for ECM and adopts a flexible electrode that can be deformed during the machining process as the tool cathode, which improves machining flexibility and provides a valuable reference to promote the ECM of complex profiles.

With the increasing requirements for accuracy and integrity of machining under severe application environment, electrochemical discharge machining (ECDM) has evolved continuously for fabricating micro-holes. The method can be categorized into two types based on whether the material being machined is electrically conductive or non-conductive. Most research to date has been focused on non-conductive materials, with numerous introductory review articles. However, despite a growing number of studies of machining conductive materials, there is a lack of systematic analyses and summaries. Therefore, the purpose of this paper is to fill an important gap in the literature by presenting a comprehensive review of the research and development of ECDM technology for processing conductive materials, especially micro-holes. First, the characteristics of this method are summarized. Second, the development of this method and the mechanism of discharge are compared and analyzed. Third, a discussion is given on how machining performance is affected by parameters such as solution conductivity, electrical parameters, tool electrode structure, and workpiece material. Also, to enhance the machining quality, some auxiliary ECDM measures are presented. Finally, future prospects and trends of ECDM are identified.