Research On Numerically Electrical Machining Of3D-Flow Closed Impeller

3D-Flow closed impellers have many advantages, such as, good performance at strength andrigidity, high efficiency and high dependability, so this kind of impeller increasingly is being used inmore frequently in the design of advanced turbomachines, which are used in aerospace and advancedthe field of turbo machinery. However, due to the complexity, poor machining reachability, and theextensive use of hard-to-cut materials, integral production of3D-Flow closed impellers has become acommon technical problem in the advanced manufacturing.Based on existing typical electrical discharge machining (EDM) technology of big size3D-Flowclosed impeller, research the overall manufacturing process technology of small size3D-Flow closedimpeller with splitter blades and quite crankle channel. After discussing its structural characteristics,developed a numerically controlled electrical discharge machining (NC-EDM) process plan formachining complex curved3D-cavities; a multi-part, multi-electrode, multi-step electrical machiningtechnique is proposed. The study focused on several key technologies for NC-EDM of the3D-Flowclosed impeller. The topics in this thesis include but not limited to: division of the3D-Flow cavity,choice of the way of electrode orbiting, design and production of electrodes for near-profiled tools,design and production of the special fixture for NC-EDM, arrangement of processing procedures,machining allowance distribution among the processing procedures, and NC programs coordination.Combine the NC-EDM and digital technology to a new machining technology and it focus ondigital modeling and simulation during the process of production. Digital technology was usedthroughout the whole design and machining process of study. By using uniform production standardsand data transformation and redevelopment software on UG, an uniform model for digital simulationwas built up, and have achieved: dynamic assembly of electrodes and the fixture; simulation for theprocess of EDM; quick correction of electrodes and their NC-tracks; greatly improved the efficiencyof product design; reduced the amount of testing work.Based on the above process technology study, the trial-manufactured of a typical3D-Flow closedimpeller with is completed. By conducting trial-manufacture, we thoroughly studied the problemsrelated to several key steps during this process, such as parameter determination, fixtures installationand location, the tool-electrode setting accurately, digital tests on the products, and data analysis, andproposed solution for each problem. The testing results from measurement showed that the final3D-Flow closed impeller product produced in our test trial perfectly meets all the designedrequirements.