Basic Research Of Precision Electrochemical Broaching

With the continuous improvement of aero-engine performance,powder metallurgy super-alloy and other difficult cutting materials is widely used in mortise structure of turbine disk.The machining accuracy requirements of mortise structure are higher than before.The existing mortise processing technologies such as mechanical broaching have been unable to meet the manufacturing requirements.Electrochemical broaching has significant cost advantages because it has the characteristics of machining regardless of the mechanical properties of materials,no tool wear,high efficiency.However,the machining accuracy of conventional electrochemical broaching cannot meet the requirements of turbine disk mortises.So it is urgent to improve the machining accuracy of electrochemical broaching.In this paper,the method of precision electrochemical broaching is studied.The main research contents are as follows:(1)A high-precision electrochemical broaching with small machining gap was proposed.Through in-depth analysis of the electrochemical broaching model,the necessary conditions of electrochemical broaching with small machining gap were obtained.Reducing tool rase angle and increasing feed rate will help to reduce machining gap.The electric field simulation and multi-field coupling simulation of electrochemical broaching were carried out.The simulation results showed that the short electrolyte path length was conducive to improve the processing stability of electrochemical broaching.(2)The effect of machining gap on the machining accuracy and surface quality of precision electrochemical broaching enlarge holes were mastered.The experiments of precision electrochemical broaching enlarge round holes and oval holes were carried out.The experiment results show that with the increase of the feed rate of electrochemical broaching,the roundness and surface quality of the holes are significantly improved.Based on the analysis of the profile of the partially machined specimen,the evolution law on machining accuracy and surface quality of precision electrochemical broaching enlarge hoes were preliminarily grasped.The simulation analysis and experiments of the auxiliary anode in the precision electrochemical broaching were carried out.The results show that the auxiliary anode can effectively suppress the influence of the fringe electric field on the processed surface.(3)The experiments of precision electrochemical broaching mortise were carried out.Taking a blade mortise ratio as a research object,the fixture and cathode for machining mortise were designed.The experiments of precision electrochemical broaching were carried out at different feed rates.The results show that with high speed and small machining gap,the cross-section consistency of the mortise is improved.An precision electrochemical broaching machining mortise with auxiliary anode test was carried out.The suppression effect of the auxiliary anode on the fringe electric field was verified.