Research On Discharge State Recognition And Processing Technology Of Liquid Phase Electrode

In the field of micro-electro-discharge machining(?EDM),friction losses in the solid electrode machining will negatively influence the precision and efficiency of the processing.Besides,micro electrode manufacturing artifacts are sophisticated and with high costs.Facing with this problem,our lab suggests replacing solid electrode with liquid metal soft electrode to machine,and making micro electrode friction selfcompensation by means of the flow characteristic of liquid.At present,this method has yielded some fruits.This essay focuses on gap discharge signal detecting system and identifying method of discharge state,the rule of terminal electrode forming under the pressure.Furthermore,it is applied to subsidiary machining processing of multi-physics to further improve machining precision and efficiency.In the detection of gap discharge signals,gap discharge voltage and gap discharge current detection system based on the high-speed data acquisition card is set up.The theoretical calculation and Multisim simulation analysis are carried out on the key parts of the system.Finally,using set-up system into the actual acquisition task can achieve up to the sampling rate of 100 k Hz.In the discharge state recognition,the sort of liquid metal micro EDM discharge state under RC power are confirmed in the first place,which,only short-circuit state,open-circuit state and spark discharge state are considered under the condition of kerosene working fluid.By analyzing the development tendency of the existing discharge state recognition methods and actual machining condition,this essay introduces the Temporal Convolution Networks(TCN)model to complete the classification task of gap discharge signal sequence in a period of time.The classification accuracy can reach 98%.Combining with the statistic model,spark rate,short-circuit rate and open-circuit rate of the corresponding time period can be obtained.In the forming of liquid metal terminal electrode,the hydrodynamical model based on Navier-Strokes Equation and Cahn-Hilliard Equation is introduced to describe the forming process and movement of terminal electrode.COMSOL Multiphysics software is used to complete the simulation.At last,the relationship among the inlet pressure,regularity of terminal forms and velocity field within pinhead is acquired by calculation.Finally,machining experiments which is assisted with multi-physics fields are carried out based on the detecting system and recognition methods.Multi-physics fields includes high-voltage electric field and rotating magnetic field.Experiments aims to find out the influence of using multi-physics field on machining precision,and come to a conclusion that both the high-voltage electric field and rotating magnetic field have positive effects on the machining precision within certain limits.