Basic Research On Process Art Of Electrochemical Machining Of Integral Closed Impeller

In modern manufacturing process, closed impeller is produced by welding. Thermal stress from welding process inducing geometrical distortion of the impeller, causing accuracy error , affecting the aerodynamic performances and serviceable life. Electrochemical machining (ECM), is one of the non-traditional machining processes, which is an anodic dissolution process of workpiece in a flowing electrolyte where the shape of the tool as cathode is copied into the workpiece as anode with the removal of the anode ion by ion. it generates no residual stress or distortion into workpiece. ECM is widely used to machine integral turbo of aeroengine, the structure of closed impeller is similar to integral turbo, the paper researches on how to use ECM to machine the closed impeller.The way ECM of closed impeller has connections with hole ECM. To find out the major factor that will affect the process of ECM impeller, an ECM rectangle hole experiment is designed. According to the results, a conclusion is made that the major factor of unstable ECM process is unequal flow distribution. Computational fluid Dynamics software FLUENT is used to simulate the flow model of the experiment process. Numerical Simulation and Experiment are unification, and an optimization method of the tool electrode structure is given.According to the structure of F8 impeller, the paper give an ECM processing art and design the fixer and tool electrode. It can shape the workpiece in one feed movement with single tool electrode. FLUENT is used to simulate the process flow of the art. The results indicate that there is vortex in the machining gap, which may cause accumulation products of the electrolysis and induce short circuit between the two electrodes. So this art is unfeasible for ECM of F8 impeller.To resolve the problem, tool electrode and feed mode are improved, two new processing arts are given. Based on the simulation of machining flow for the two processing arts, both of them can be used for the ECM of F8 impeller, because the flow distribution is equal for both.