Research On Micro EDM Process Of Split-Flow Core For Micro Heat Pipe Extrusion Dies

With the development of new generation satellites in the direction of high resolution,high precision,and miniaturization,the payload of satellites is highly integrated,and the local heat flux density has increased dramatically.As a result,the lifespan of star-use electronic devices has been greatly reduced,and micro-heat pipes have been obtained in terms of heat dissipation of electronic devices.Widely used.In order to meet the low-cost,high-volume production requirements of micro-heat pipes,micro-heat pipe processing commonly uses metal micro-extrusion molding technology,in which the split-core core as a key component to form the shape of the heat pipe cavity,its high-precision machining for high-quality micro-heat pipe Manufacturing is of great significance.In this paper,by analyzing the structural characteristics of the shunt core,and adopting a combined assembly-processing scheme,the shunt core is divided into gears and core rods.Among them,the gears are 2.84 mm wide,7mm long,and the deeper diameters are larger,smaller in size,and require higher machining accuracy.These are the main processing difficulties for the shunt core.Firstly,finite element software ANSYS was used to establish the temperature field simulation model of V40 tungsten steel micro-EDM and based on the simulation model,the influence of material characteristics and discharge concentration on the machining process was analyzed.Through the introduction of the "Life and Death Unit Technology" to get the effect of the pulse discharge erosion,it was found that the high melting point of the V40 tungsten steel makes the single pulse material removal less.When the discharge spot is concentrated,the reduction of the pulse effective loading area reduces the material removal rate of the pulse.At the same time,due to the influence of the residual temperature field,the discharge spot concentration area is always at a high temperature.For the gear-like machining,the basic experimental research on micro-EDM is carried out.Firstly,the effects of machining parameters such as electrical parameters,wire tension,and feed rate on the material removal rate and surface quality during the machining process are analyzed.In order to solve the problem of discharge concentration and wire breakage in the machining process,the discharge point position distribution of the gear-like wire EDM machining process was detected based on the potential difference method,and the relationship between the machining parameters and the distribution of discharge points was studied.In order to achieve the two-objective optimization of the material removal rate and the distribution uniformity of the discharge spot,two objectives are optimized based on the NSGA-II multi-objective optimization algorithm.Finally,the processing experiments of the split cores are performed.First,the micro discharge wire cutting technology is used to process the split-core core gears,and the process parameters obtained by optimizing the two goals were used to compensate for the machining gaps in the machining process;then,micro-EDM milling was used.The technical processing gear shaft is designed for the positioning and clamping error of the secondary clamping in the milling process,and a type of gear milling jig is designed.Then the mechanical core grinding and the mirror discharge technology are used to process the core rod and perform with the gears.Assemble and realize the manufacture of the shunt core.