Optimization and experimental study on cathode structure of electrochemical machining titanium alloy inner helix

In order to solve the problem of gap flow field divergence and poor forming accuracy in the electrochemical machining (ECM) titanium alloy inner helix, the pull reverse flow and pull downstream cathode physical models as well as the simulation models of machining gap flow field are established respectively in this paper. Different inclination angles of the liquid supply hole effected on the pull downstream cathode rotational flow field uniformity were explored. The results showed that the gap flow field distribution of the pull downstream cathode is better than pull reverse flow cathode, and the distribution of the rotational flow field formed when the inclination angle of the liquid supply hole achieves 40° is relatively uniform. Under the condition of voltage 12 V, cathode feed speed 15 mm/min, composite electrolyte 3%NaCl + 10%NaNO3 + 6%NaClO3, electrolyte temperature 30 °C, and electrolyte inlet pressure 2 MPa, the 800-mm length of titanium alloy inner helix sample was machined stably and reliably by the pull downstream cathode structure, which surface roughness is Ra0.8 μm.