Research On Atomization EDM Ablation And Electrochemical Composite Milling Machining

Traditional EDM is limited by the energy output of pulse power supply,so the machining efficiency is low,which is difficult to meet the machining requirements.Although EDM ablation machining solves the problem of machining efficiency,it also brings serious surface deterioration layer,which affects the service performance and service life of parts.In this paper,the atomization EDM ablation and electrochemical composite milling machining technology is proposed.The working medium is "electrolyte-oxygen" atomization medium.There are two characteristics of this machining technology.One is that the main etching energy is the chemical energy released by the combustion of the material itself.The other is that the surface of the workpiece is trimmed by micro electrochemical machining as an auxiliary means to reduce the metamorphic layer and achieve the purpose of improving the surface quality.Specific works were as follows:(1)The experiment platform of atomization EDM ablation and electrochemical composite milling machining was designed and built.It mainly includes the construction of "electrolyte-oxygen" uniform mixing atomization device,gas and liquid supply system,and the anticorrosive measures are taken for the corrosiveness of electrolyte.The experiment platform can adjust the pressure of oxygen and liquid,electrode speed,etc.according to different processing requirements,and create a reliable processing environment,which is the key guarantee for normal test.(2)The machining characteristics of atomized EDM ablation milling are analyzed.The macro machining process is mainly divided into two stages: the activation of EDM and the combustion of activated metal matrix.Based on the water-based atomization medium,the model of inter electrode breakdown is established.Through energy analysis,it is proved that the energy released by combustion reaction can heat enough metal to the activation state,so that the atomization reaction can continue.(3)This paper discusses and analyzes the basic principle and machining characteristics of the atomized EDM ablation and electrochemical composite milling machining.According to the analysis of the basic principle of composite machining,there are three machining states in the process,namely,the recycling machining process in three ways: micro electrochemical machining,electrolytic discharge ablation machining and EDM ablation machining.The typical electrolytic discharge ablation machining process consists of three micro stages: electrolysis stage,discharge breakdown stage and rapid ablation removal of metal matrix.(4)This paper analyzes the process characteristics of atomized EDM ablation and electrochemical composite milling machining.Three machining methods,composite machining,atomization EDM ablation milling and conventional EDM milling,are used to carry out the comparative test of straight groove machining.The results show that the material removal rate of atomized EDM ablation and electrochemical milling machining is 11% higher than that of atomized EDM ablation milling,which is 12.2times as much as that of EDM;the relative loss of electrode volume is reduced by 49.3%;the thickness of deterioration layer of machining bottom and side is reduced by 63.2% and 58.4% respectively.(5)In this paper,the experimental study on the technological law of the die steel Cr12 was carried out by using the atomization ablation and electrochemical composite milling machining.The influences of electrical and non-electrical parameters on ablation characteristics(material removal rate,electrode volume relative loss)are analyzed.The results show that the discharge energy is an important factor affecting the material removal rate and the relative loss of electrode volume.In the non-electric parameters,the oxygen pressure increases,but the material removal rate tends to be stable due to the limited number of activated matrix;the increase of liquid pressure reduces the oxygen content,and finally leads to the decrease of material removal rate and the relative loss of electrode volume.(6)The experiment of cavity machining was carried out by atomization EDM ablation and electrochemical composite milling machining.According to the characteristics of cavity machining,the optimal parameters and routes are determined from five aspects: milling cut in mode,layered milling depth,electrode loss compensation,electrode motion path overlap rate and machining path planning,and finally the cavity with high precision is machined,which proves that atomization EDM ablation and electrochemical composite milling machining technology is a feasible machining method.