Analysis and optimizing of the special-shaped flow field during co-rotating electrochemical machining of rib structures on the inner wall

In aerospace, there are many large thin-walled circinate parts that are usually made of difficult-to-process materials such as superalloys, nickel-based alloys, and titanium alloys, and their inner walls have complex structures. Inwall co-rotating electrochemical machining (ICRECM) is a novel machining method to manufacture these parts with high efficiency and precision. In ICRECM, the processing area is extremely narrow inside the anode workpiece and the relative motion of the electrodes is complex, resulting in a very tortuous and changeable flow channel. Therefore, it is a challenge to make the electrolyte flow quickly and evenly through the processing area to carry away electrolytic products and heat. According to the characteristics of the special shaped flow field, four kinds of electrolyte supply methods were proposed, including unilateral electrolyte supply, bilateral electrolyte supply, bilateral alternating electrolyte supply, and the combination of bilateral alternating electrolyte supply and auxiliary supply of electrolyte from the cathode. The simulation analysis and experimental verification of the four electrolyte supply methods were carried out, respectively. The flow field distribution of unilateral electrolyte supply and bilateral electrolyte supply is poor, which cannot meet the processing requirements. The method of bilateral alternating electrolyte supply ensures that the flow velocity on both sides of rib structures is the same within one cycle, which solves the problem of uneven material dissolution on both sides of rib structures. The combination of bilateral alternating electrolyte supply and auxiliary supply of electrolyte from the cathode has an excellent flow field distribution. The height of the processed rib structure is as high as 9.6 mm, and the symmetry deviation of the profile is less than 0.06 mm. This fully demonstrates that high rib structures with good profile symmetry can be machined by ICRECM.