Applied Fundamental Research On Precise ECM Of Diamond-hole Grille

With the advance of aerospace technology,aerospace vehicles are ever more dependent on the structure performance and light weight.Therefore,a lightweight and efficient structural form is pursued all along by countries around the world.Grilles with special-shaped holes,lightweight and efficient structures,with their significant wave absorbing performance and radar wave shielding ability,are considered an ideal structure for Aerospace vehicle and stealth aircraft.Compared to conventional machining,electrochemical machining(ECM)is a superior method for creating the needed shapes,as it can provide the needed surface quality,and efficiently shape complicated contours and profiles on hard metals while remaining free of tool wear,residual stress and a metamorphic layer.The outstanding technical and economic effects of mass production of these grilles shows the possible implications of this technique.However,the drawbacks of electrochemical machining,such as its complexity,instability,and that it is subject to multiply factors,restrict its wide application.In view of the question concerning the low precision and stability of the electrochemical machining of special holes,this paper,taking diamond holes as the research object,performed experimental study on precise electrochemical machining of diamond holes with the self-developed experimental system.The main researches include the following aspects:(1)Development of the overall plan for the process of electrochemical machining of diamond holes.Based on the theory of electrochemical anodic dissolution,the factors affecting the accuracy and stability of electrochemical machining of diamond holes were analyzed combining with the characteristics and the machining difficulties of diamond holes.The measures to improve the accuracy and stability of electrochemical machining of diamond holes were discussed,which provides a theoretical basis for the experimental research of the precision electrochemical machining of diamond holes.(2)Design of the fixture for the electrochemical machining of diamond holes.The cathode and groove structure was designed.In view of the question concerning the non-uniform flow field in the machining gap,the groove structure and the inlet and outlet pressure of electrolyte was optimized.The cathode connecting rod and back pressure cavity was designed reasonably according to the test condition of diamond-hole electrochemical machining.Finally the fixture could meet the requirements of the tests.(3)The process experiments of precise electrochemical machining of diamond holes were carried out.The single-factor comparative tests between pulse electrochemical machining,composite feed electrochemical machining and packet pulse-matched electrochemical machining modes were conducted.The trial machining of diamond holes was carried out with optimal machining mode and the combination of process parameters base on the results of process tests,and good results were obtained.Results indicated that the packet pulse-matched ECM mode with its capacity to dramatically advance the stability and localization of ECM is proven to be the optimal choice for precise ECM in the future.