Experimental Study On Electrical Discharge Machining Process For Micro Holes And Array Holes On Nickel-base Superalloy Single Crystal Parts

With the continuous development of aerospace,automobile manufacturing,biomedical and other scientific and technological fields,micro-scale structures are becoming more and more important,and micro-holes and array micro-holes are the most basic and the most capable of reflecting the level of processing technology.With the rapid development of industry in the 21st century,micro-scale processing technology has been rapidly improved.Among them,EDM technology has no macroscopic force in its processing,and is not limited by physical properties such as strength,stiffness and hardness of the material.In the field of microscale processing,it has been the most effective way to solve related problems.In this paper,the lowspeed wire EDM(LS-WEDM)machine tool was used to process micro rotary parts by setting up high precision waterproof rotary mechanism.Based on the principle of EDM,micro cylindrical electrodes,micro spiral electrodes and array electrodes with different structures were prepared,and experimental research on the processing technology of micro-holes and array micro-holes was carried out,which provided theoretical reference for the processing of micro-holes and array micro-holes with high quality,high efficiency and low cost.The main research contents of this paper are as follows:(1)Simulation study on gap flow field during micro holes and array micro-hole processing was carried out.Based on ANSYS FLUENT software,simulation study was conducted on the movement of gap fluid and electrical corrosion products in the process of micro-holes and array micro-holes processing by micro cylinder electrodes,micro spiral electrodes and array electrodes.The single micro-holes and array micro-holes gap fluids were modeled by simulation.The up-and-down lift motion of the electrode was simulated by dynamic mesh technique.The influences of electrode structure parameters,lifting height,lifting speed and other process parameters on the movement of working media and electrical corrosion products are analyzed,and the corresponding rules were summarized.(2)Experimental study on the processing technology of single electrodes and single microholes was carried out.The micro cylindrical electrodes and micro spiral electrodes with different diameters and lengths were prepared by low speed wire EDM machine.Micro-holes processing experiments were carried out on nickel-base superalloy single crystal parts.Through experiments,the effects of different electrode structures(spiral groove depth and pitch,etc.),lifting speed and lifting height on the accuracy and quality of the single micro-holes and electrodes loss were analyzed,and the corresponding process methods were summarized.(3)Experimental study on the processing technology of array electrodes and array microholes was carried out.Square and circular array electrodes were prepared by EDM,and the effects of different processing methods on the dimensional accuracy,surface quality and processing efficiency of the electrodes were investigated.Based on the experimental research on the processing technology of array micro-holes,the influence of processing parameters(such as lifting speed and lifting height)on the precision,quality and consistency of array micro-holes was obtained,and the best process plan was given.(4)Experimental study on the processing technology of irregularly-shaped micro-holes and microarray structures was carried out.The stepped electrodes and the D-shaped electrodes were prepared and micro-holes processing experiments were performed.The rectangular microarray electrodes were prepared,and rectangular array grooves were processed.At the same time,the processing of the micro array pit structure on the flank of the micro-milling cutter is realized by making full use of the single electrodes.