Study Of Erosion Processing Capacity And Morphology Of WEDM In Gas

With the rapid development of economy,requirements on industrial parts processing accuracy is becoming higher and higher.WEDM in gas has the characteristics of small processing surface roughness value,the high straightness precision,the narrow discharge gap and the processing surface have no electrolytic corrosion,etc.It is suitable for multiple cutting and finishing processes.But with the in-depth study of WEDM processing technology,it is found that the process is a very complex physical change process.At the present,lacking of accurate prediction of EDM process,the actual processing has the problem of low machining efficiency and speed.So it is necessary to further study the mechanism of discharge for WEDM in gas.Because of the problems above,we establish processing physics and heat transfer mathematical model of single pulse discharge in WEDM in this paper.By using ANSYS software,Cr12 Mo V workpiece materials' temperature field in atmospheric medium with single pulse discharge is simulated.On the basis of a single pulse,temperature field of two pulses is simulated.The temperature in the second pulse simulation is greater than the single pulse,the simulation proved the mutual influence between temperature field.In order to simplify the WEDM removal volume calculation,the finite element simulation of the electric erosion pit model is simplified to the ball model and its rationality was verified.In this paper,we establish a uniform cutting erosion volume model.According to the degree of the overlap electric pits,its distribution can be divided into four categories.This paper induced the volume calculation formula of the overlapping spherical cap under the condition of knowing its overlapping distance deduced the removed volume formula of a single electrical erosion pit.The continuous discharge electric erosion pit volume model is established under the condition of uniform distribution of the electric erosion pit.The ball model was taken as a single electric erosion pit model.Using the theory of uniform distribution,removal volume of the continuous pulse discharge was calculated.The calculation got the removal volume.Using the measured results,find out the actual removalvolume.By contrasting theory volume removal with the actual removal volume,the viscoelastic layer thickness and the volume of the viscoelastic part was got.Radius,depth and theory electric erosion pit volume were revised by the volume of the sticky part.The multiple pulse electric erosion pits have been assumed as a rectangle and its rationality was proved.On the basis of temperature field simulation,We study the microstructure of the WEDM surface in this paper.The gas-liquid surface topography,surface machining deteriorated layer and the surface average roughness Ra,maximum roughness Rz have been studied respectively.Surface topography state which got in gas WEDM was more flat than that in liquid WEDM.Gas discharge pits were large and shallow and liquid(emulsion)pits were deep and small.