The Simulation Sutudy Of The Distribution Of Debris And Bubbles In The Gap During EDM

During the process of EDM,the movement and distribution of erosions and bubbles in the machining gap have a very important effect on the machining efficiency,electrode loss and surface quality.If the erosion in the processing gap can not be timely and effective discharge,the gap between the erosion and bubbles' concentration increases,it is prone to secondary discharge,drawing arc,short circuit,discharge concentration and so on.It will not only increase the electrode wear,affect the forming accuracy,reduce the processing rate,but also the processing can not continue seriously.Therefore,in the EDM process we should take effective measures to promote the erosion of the gap between the flow field.The knife movement is widely used as an effective way.Firstly,based on the mechanism of EDM,the three-dimensional solid-liquid-gas three-phase flow model of the gap flow field during EDM process is established.The discharge parameters were selected by experiment,and the discharge gap was estimated to establish the geometric model of the gap.Based on the experimental observation of the bubble generated by the pulse discharge,the generation and motion model of pulsed discharge bubbles are established in this paper.Through the measurement of the processing speed of the EDM,the size of the eroded product produced by the pulse discharge is calculated and the generation model of the erosive material is established.The simulation model of single spark discharge process is determined.Secondly,based on the establishment of single pulse's discharge simulation model,the simulation model of the continuous discharge process without lift is established according to the pulse frequency.The distribution of the erosion and the bubbles in the gap during the continuous discharge process are analyzed,and the causes of the sharp angle loss during the continuous discharge of the spark are discussed.Based on the simulation model of continuous discharge process without lift,a simulation model of continuous discharge process was established to study the influence of lift movement on the electrode wear and the processing speed.Finally,this paper carries out different experiments on the height of the knife,the frequency of the knife,the speed of the knife,the depth of the machining and the diameter of the electrode.Through the comparison of experimental and simulation results,the simulation model of single pulse discharge,the simulation model of continuous discharge process and the simulation model of continuous discharge process of lifting knife are validated.