Key Technologies Research On Electrochemical Machining Of Blisk Multi-tunnels

Blisk is one of the core components of aircraft engine, and its quality determines the engine’sperformance and life. Blisk combines the blades and the disk together, instead of making the usualblade tenon tooth and disk groove connected by locked chip, which can make the engine’s structuresimple, engine’s weight lighter.Besides, blisk can eliminate the transpiration loss in tenon tooth anddisk groove with traditional spit blade–disk structure, which can improve the engine’s work efficiencyand thrust-weight ratio.Currently, blisk is becoming more and more lightweightly and integrally. Adopting blisk is keymeasurement of making engine’s reliability better and thrust-weight ratio higher, so blisk is morepopularly used in advanced air engines and new rocket with high thrust-weight ratio. Blisk machiningprocess includes computer numerical control(CNC), electric discharge machining andElectrochemical machining(ECM). Contrast to traditional process, ECM has many advantages such asno electrode loss, high efficiency, low production cost, and no restriction from mechanical propertiesof metals, etc.These advantages can satisfy the need of machining of blisk channel, so ECM plays animportant role in blisk machining. ECM of blisk is divided into two steps: channel rough machiningand blade surface precise machining. Blisk channel rough machining is indispensable process of bliskECM and is the foundation of blisk precise machining. Compared with foreign aircraft enginemanufacturing country, ours blisk channel machining is lagging behind, mainly as lacking ofcorresponding equipment and matured process.With the rapid development of ours air industry, blisksare required urgently on which this paper expounds the research on ECM of blisk channel.Blisk machining is all the time a difficult problem of machinofacture as blisks have complexstructure and blade profile as well as high machining precision. Currently, aero engine’s demand can’tbe satisfied with traditional processes including low machining efficiency in blisk channel machining,tool’s interference with workpiece, high processing costs, and low uniformity distribution offollowing process margin. For solving these problems, this paper carried out interrelated research inseveral aspects:1.A method of multi-cathodes being used in machining is raised to achieve ECM of bliskchannels with multi-cathodes simultaneously feeding. The method can improve the efficiency of ECMof blisk channel and decrease the production cycle. Currently，three cathodes can be simultaneouslyused in machining，with which the channel processing time is redused by2/3. 2.The movement path of electrode and workpiece is designed and optimized. For improve theuniformity of channel surface margin, the method of cathode revolving in the process is raised，thespace movement path of tool cathode relative to workpiece is designed and the finishing margin ofbilsk channel is analyzed. The movement path of cathodes is optimized based on ECM formingdiscipline.Relevant experiment reveals that the path is reasonable.3.The flow field of ECM of blisk multi-channels is designed. Tube cathodes are proposed to beused in ECM of blisk channels.The flow mode that electrolyte flows into one end of the cathode andout of the outflux on cathode pipe wall is designed.The distribution of groups of holes or seams isoptimized to achieve uniform flow field. Flow mode is designed and optimized，gland even flow bushin which the electrolyte flow path can be controlled is developed, for making the uniformity of flowfield further improved. Incompressible three-dimensional model is established and the flow fieldnumerical simulation is carried out with Fluent. The flow characteristics of ECM is analyzedtheoretically and corresponding clamp is designed.4.An ECM machine equipment for blisk channels is developed. The machine system includesfour parts, such as machine itself, power system, electrolyte circulation system and control system.For improve the efficiency of ECM of blisk channel, multi-cathode clamping plate is designed forcontrolling multiple cathodes simultaneously moving to achieve ECM of blisk channels withmulti-cathodes.A CNC system of ECM of blisk channels is developed. The system has many powerfulfunctions, such as tool setting control, servo feed, process monitoring and short circuit protection,which make the ECM machine more reliability, stability and automatic. The machine runs steadilyand can meet the need of ECM of blisk channels.5.The process program of blisk multi-channels ECM is designed. In connection with many linksuch as feed mode, path correction, flow field design, multi-cathodes being used in process, ECMexperiments are carried out for checking the feasibility of these plans. The experiment is based on theprinciple of high efficiency, for machining blisk with small margin and well uniformity. In connectionwith a blisk of some air engine, experiments are carried out. The result reveals that machining onechannel only takes20minutes, which increases the efficiency remarkably. The experiment result thatmachined blisk channel can meet the need of the finishing process.