Study On WEDM Discharge Point Distribution Of Large Thickness Workpiece Based On Quad-tree Method

This paper focuses on WEDM discharge point location of large thickness workpiece based on quad-tree method,which is important for optimizing machining parameter,improving machining precision,and working efficiency.This paper focuses on 80 mm thick workpiece(large thickness workpiece)machining features and compare with that of 40 mm thick workpiece(ordinary thickness workpiece).Owing to the increase of workpicce thickness,the discharge gap and discharge environment are changed,so the machined surface features of large thickness workpiece are different from those of ordinary thickness.The distribution of discharge point can be obtained by studying the discharge point location of large thickness workpiece,and processing parameters can be optimized according to distribution characteristics.In this paper,the detection of WEDM discharge point location of large thickness in gas was studied.This paper analyzed the mechanism of electric discharge machining in different processing mediums,and the influence on WEDM discharge location,which shows as the effect on processing quality in macroscopic view.The method of evaluating the average degree of multiple fields were compared.The characteristics of electrical discharge were also analyzed.The visual evaluation method was improved,and the four point tree image segmentation was used to partition the discharge point distribution map.By comparing different detection principles of electric discharge machining,a proper detection method was chosen.Setting an evaluation of WEDM discharge location’s uniformity system based on Labview’s word.After that,several groups of accuracy verification experiments of discharge point detection were carried out to perfect the setting of parameters of discharge point detection system,including calibration experiment,variable cross-section cutting experiment.The processing results of 40 mm and 80 mm thick workpieces were compared,and the similarities and differences of discharge point distributions between two processing surface were observed.Then WEDM experiments of large thickness workpiece were carried out,and the results of experiments in different processing parameters were evaluated.In processing tests we studied the influences of offset and worktable feed on WEDM discharge location and discharge efficiency in medium as emulsion liquid DX-1,atmosphere,and water mist.In the end,the influence of water content of water mist on the distribution of discharge point was studied in ultrasonic water mist.Combined with research of the principle of WEDM,the curves of the experimental results were compared.The processing parameters were optimized by studying the distribution state of the discharge point on the micro scale.