Study On High-frequency Pulse Electrochemical Discharge Combined Precision Milling And Grinding Technology

Electrochemical discharge machining(ECDM),is an emerging machining technology dealing with weak-conductive material.The machining mechanism is complex because electrolysis and etching reaction is involved during the process.As a result,machining quality is difficult to be effectively controlled.In order to develop and improve the ability of ECDM,this paper adopts high-frequency pulse in ECDM and combines it with precision milling and grinding method,in which a tungsten steel electrode that covered with diamond abrasive grains is used to study the machining characteristics on optical glass materials.The goal is to shorten machining time,improve localization of the process,and reduce the cracking phenomenon and heat affected zone around the outlet.The paper is divided into three main parts:The first part is the establishment of an experimental platform for electrochemical discharge milling and grinding.Based on mathematical deduction of a single electrochemical discharge energy,a two-stage energy transfer model is built using ANSYS simulation,which shows that the material softening depth range is between 5.51μm(650℃)～9.03 μm(800℃).Added with the empirical thickness of the gas film and the liquid film inside the machining gap,the size of abrasive grains is determined to be around 35μm to ensure the abrasive grains can valid contact with the softening zone on the surface of glass work piece;Under the condition of plastic scraping,theoretical relationship between machining feed speed,electrode peripheral speed and the distance of adjacent abrasive grains is calculated.The second part is the research on the technological rules of electrochemical discharge milling and grinding.A material removal simulation is established through ABAQUS to analyze the material removal rate,surface roughness of the workpiece and force on electrode during the course of machining,providing a reference for feed parameters in actual machining.In the third part,Orthogonal experiment method is introduced to determine the optimal combination of experimental parameters for a complex typical structure fabrication on glass.Compared with conventional ECDM,high-frequecy pulse electrochemical discharge milling and grinding has greatly improved the machining efficiency,localization and surface quality of the machined area;A glass microstructure of Shandong University emblem is performed under the parameter combination of working voltage 37V,pulse frequency 7500Hz,electrode speed 3000r/min and feed speed 5μm/s,which is a demonstration for the excellent machining ability of the machining method proposed in this paper.