Experimental Study On Wire Electrical Discharge Machining Finishing Machining Of Variable Thickness Workpiece

WEDM technology is widely used in the field of mechanical manufacturing and processing.WEDM in water mist medium uses water mist as the medium.Unlike traditional liquid media,it is necessary to study the mechanism and characteristics of electrical discharge machining of water mist medium.Previous studies have shown that wire cutting in water-mist medium can improve surface quality and cutting speed,but when processing variable thickness workpieces,in order to ensure the consistency of processing accuracy,the processing parameters of different thicknesses are different,and it is necessary to obtain optimized parameter groups through experiments.Moreover,there are few studies on variable-thickness finishing in water mist,and a lot of experimental research is needed to obtain a cutting process suitable for variable-thickness workpieces,so that the surface consistency of the variable-thickness workpieces is better after processing.The main research contents of this article are as follows:First of all,the mechanism and characteristics of WEDM discharge machining in water mist medium are analyzed to obtain a machining theory suitable for water mist mid wire cutting;the machining characteristic test of large thickness and variable thickness workpieces is carried out to obtain the influence law of thickness change on various indicators,and The influence of electrical parameters on the processing of large-thickness workpieces.Adjust the non-electrical parameters according to the obtained rules to reduce the impact of non-electrical parameters on surface quality and processing efficiency.Secondly,the rough machining test of the variable-thickness workpiece in the emulsion is carried out,and the orthogonal experiment is carried out by Minitab software to obtain the influence law of each processing parameter on the process index.The weight of the cutting depth,surface roughness and cutting speed is selected by using the analytic hierarchy process weighting The values are 50%,20%,and 30%,respectively,and the optimal processing parameter group is selected,so that the variation depth of the cutting depth of the workpiece surface of variable thickness is9.3%,the average cutting speed is 36.15 mm~2/min,and the surface roughness is less than 3.9μm,and the change amplitude is less than 15%,indicating that the surface roughness after the first roughing is good and the cutting speed is large.Analyze the medium and parameters of the secondary cutting,select the appropriate processing medium and processing parameter range for the secondary cutting.Finally,the finishing experiment in the steam water mist was carried out,the orthogonal experiment was carried out according to the electrical parameters selected in the previous experiment,and the weights of the cutting depth,surface roughness and cutting speed were selected to be 34.3%,41.2%,24.5%,The optimal processing parameter group within a given discrete processing parameter range is preferably selected,so that the change amplitude of the cutting depth of the variable-thickness workpiece is reduced to 5.02%,the change amplitude of the surface roughness is reduced to 8.04%,and the cutting speed is greatly improved.The response surface analysis method is used to establish regression models of cutting depth,surface roughness and cutting speed.The comprehensive evaluation model after weighted normalization is optimized by MATLAB for multi-objective optimization,and the optimal processing parameters with continuously changing parameter values within the parameter range are selected.Through the comparative test of the design,the results show that the variable parameter cutting can greatly improve the surface consistency and processing efficiency of the workpiece with variable thickness.