| Tungsten alloy is a duplex alloy based on tungsten with a small amount of nickel,iron,copper,cobalt and other elements.It has excellent characteristics such as high density,high hardness,high thermal conductivity and high temperature resistance,and is widely used in aerospace,military weaponry,nuclear industry,chemical industry,electrical industry and other fields,becoming an important strategic metal material of great interest.However,because of its unique physical and chemical properties,tungsten alloy products are difficult to process,tungsten alloy processing technology is poor,and the tool wear of related tungsten alloy products is serious in the process of processing,the surface integrity and surface shape precision of parts are seriously deteriorated.The processing problems of tungsten alloy seriously restrict the popularization and application of tungsten alloy.In order to solve the difficult problem of tungsten alloy machining,this paper proposes to introduce the electroplastic assistant technology of plastic forming into tungsten alloy milling,and carries on the systematic research.The main research contents and conclusions of this paper are as follows:(1)According to the current characteristics in electroplastic machining,the current distribution characteristics of electro tungsten alloy were studied by using finite element software Maxwell.The results show that the piece cross-section diameter was changed only,the absolute uniformity coefficient decreased with the increase of the piece cross-section diameter.When the cross-section diameter was greater than 40 mm,the absolute uniformity coefficient decreased and finally tended to be smooth.The absolute uniformity coefficient of the pulsed current load decreases but the overall variation is small.The frequency change of pulse current does not affect the uniformity coefficient of current.The current distribution in the cylindrical bar is more uneven than that in the rectangular bar,which indicates that the different shapes will also affects current distribution of the piece with sinusoidal wave has obvious skin effect.(2)General milling and electroplastic aided milling experiments were carried out on tungsten alloy,and the influence of milling parameters on milling force was analyzed.The results show that the milling force firstly decreases and then increases with the increase of spindle speed,and gradually increases with the increase of feed speed and cutting depth.The optimal parameter combination of common milling is that the spindle speed is 1600r/min,the feed speed is 40mm/min and the cutting depth is 0.1mm;Optimal parameter combination of electroplastic aided milling is that the spindle speed is 1600r/min,the feed speed is 80mm/min and the cutting depth is 0.1 mm.Compared with ordinary milling,the milling force produced by electroplastic assisted milling can be reduced by 46% under the same milling parameters.Themilling force is fitted to establish the milling force component model of ordinary milling and electroplastic aided milling.(3)Ordinary milling and electroplastic auxiliary milling experiments were conducted on tungsten alloy to analyze the influence of milling parameters on surface quality and tool wear.In ordinary milling,the roughness increases first and then decreases with the increase of spindle speed,increases with the increase of feed speed,and increases with the increase of cutting depth.In electroplastic auxiliary milling,the roughness decreases first and then increases with the increase of spindle speed,increases with the increase of feed speed,and increases with the increase of cutting depth.electroplastic auxiliary milling will have adverse effect on surface machining quality to a certain extent.Under the condition of electroplastic auxiliary milling,the tool wear decreases.(4)Three-dimensional modeling was carried out for the dynamic milling process of tungsten alloy by using finite element simulation soft are ABAQUS.The simulation results were compared with the experimental results,and the change law of milling force was basically consistent. |
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