Modelling And Optimization Of Wire-cut Electric Discharge Manufacture White Layer Based On Thermal And Fluid Dynamics Analysis

With the rapid development of the top manufacture industry, including mold、precisioninstrument and aerospace, the difficult-to-machine materials are making an increasinglydemand on the tools. Wire cut electric discharge manufacture has become a very importantway to manufacture advanced precision part. However, China falls behind the first classlevel in this area temporally. Taking all these conditions into consideration, with thepurpose to promote the performance of the surface, this article establishes a white layermodel to analyze and simulate by using heat transfer theory and fluid dynamics. Besides,with the help of this model, this article proposes some ways to direct the selection of theparameters to achieve the goal of reducing the thickness of the white layer and the densityof the cracks.This article begins with the study of the mechanism of the white layer formation andthe phase transformation. It turns out that the white layer is made of the melted materialwhich is not flushed away by the dielectric and solidify on the surface. As the thermalaction plays the dominant role in the white layer formation, the discharge thermal model isthe basis of the analyzing the white layer. The single pulse discharge model takes timevariable plasma channel radius, time variable material thermal parameters, Gauss heatsource, et.al. We derive from this model to establish the precast model of the white layerthickness. Besides, we find that it can promote the efficiency of the energy by increasingthe pulse current.To improve the precision further, this article analyzes the motion and distribution ofthe debris by using fluid dynamics. It turns out that whatever the parameters of thedielectric, there will always be a debris assembling area. So, his article proposes aparameters optimization method to reduce the white layer thickness and the density of thecracks by using a linearly changing flow speed. The thickness in experiments matches highly the model, which proves the accuracy ofthe established model. The results of this article helps reveal the mechanism of the whitelayer formation mechanism and provides the optimization of the surface performance withtheoretical foundations.