In order to pursue excellent performance, especially in aerospace and weapon equipment industry, components with complex structure made of difficult-to-cut material (stainless steel, titanium alloy, high-temperature alloy etc.) are more and more applied. From the rough to the finished product, the material removal rate (ranging from 10% to 90%) may be large, the machining efficiency and material utilization are low, and the machining cost would be high using traditional milling or grinding method. One kind of thin hollow cathode having high strength is developed for electrochemical machining of complex structure. This cathode is expected to improve the machining efficiency and reduce the cost. The flow field design is a key problem to be solved. Fluid dynamics numerical analysis is used to optimize the cathode structure, and the design rules of cathode are given. Experiments are carried out to prove the correctness of the numerical analysis, cutting stability, accuracy, and surface quality are improved. Finally, different structures are successfully machined on the material of TB6 by thin hollow cathodes.

TB6 titanium alloy is extensively applied in lightweight vehicles, biomedicine, and other domains because of its high specific strength, excellent fracture toughness, and excellent corrosion resistance. Electrochemical machining is a non-contact processing technology that has significant advantages in processing materials that are difficult to cut, such as cemented carbide, high-temperature alloys, and titanium alloys. To improve the consistency of deep narrow slots fabricated in TB6 titanium alloy via electrochemical machining, a sheet cathode design and experimental studies were carried out in this work. Based on a unidirectional fluid–structure coupling simulation, the influence of the stiffener arrangement on the cathode rigidity and flow-velocity distribution was studied. Furthermore, by modifying the geometry of the stiffener, the cathode deformation was significantly reduced, and flow-velocity uniformity at the cathode outlet was improved. The influence of a superimposed low-frequency oscillation on the gap distribution and the profile error of a deep narrow slot was investigated experimentally. The results revealed that when an applied voltage of 24 V, an oscillation frequency of 50 Hz, and an amplitude of 0.05 mm were adopted, a highly homogeneous deep narrow slot with an entrance gap of 0.24 mm and a side gap of 0.33 mm was machined into the TB6 titanium alloy.