Study On Machining Process And EDM Machine Tool Of Engine Blade Edge

Aero-engine technology attracts attention all around the world,which is used to evaluate the industrial technology of one country.The manufacture of aero-engine is very complex.Only few countries have the ability of aero-engine technology.In aero-engine,blade machining occupies more than 30%of the whole aero-engine manufacturing process.Nowadays,electrochemical machining(ECM)is widely used to machine the blades of aero-engine.However,the accuracy of the leading and trailing edges of blade after ECM,with e a large amount of irregular shape allowance left.In order to solve this problem,this paper proposes to use electrical discharge machining(EDM)technology to trim the edges of ECMed blade to improve the machining accuracy of blade edges to achieve the final design requirements.The main contents of this paper are as follows:(1)Development of Precision Three-Axis EDM machine tool.Because the aero-engine blades work in the environment of high temperature,high pressure and high speed,the blade materials have the characteristics of high temperature resistance,corrosion resistance and high temperature stability.Those material are difficult or impossible to be machined and the blade surface is very hard to meet the accuracy requirements by using the conventional mechanical cutting methods.Therefore,it is usually processed by non-traditional machining process.This paper uses EDM technology to trim the edge of the blade.A set of Precision Three-Axis EDM machine is developed.The hardware structure and control program of the machine are designed and developed.(2)Parameter optimization of rough and finish machining.In order to obtain the optimal process parameters of nickel base superalloy(GH4169)to meet the high precision requirements of blade,the blade machining process is divided into rough machining and finish machining.In this paper,based on the three-axis EDM machine tool,the processing parameters of nickel base superalloy were studied.In the rough machining stage,the optimal parameters of the rough machining process are obtained by orthogonal experiment:pulse width 4?s,peak current 30A,amplitude 0.9?m,vibration frequency 1000Hz,the material removal rate(MRR)can reach12.413mm~3/min;In the finishing stage,the results of single factor optimization experiment are as follows:power supply voltage 120V,pulse width 0.5?s,peak current 10A,the surface roughness is as low as 0.80?m.(3)Design and development of six axis EDM machine tool.There are mainly two methods to repair the blade edge.One is to use the formed electrode to directly machine the blade edge.The other is to use the relative motion of the electrode and the workpiece to process the high-precision blade leading and trailing edges.In this paper,the second method is used.Because the blade is a complex curved surface,it needs multi degree of freedom machine tool to machine it.Therefore,on the basis of the original three-axis EDM machine tool,three rotating axes are added,and a set of six axis EDM machine tool is designed and developed.In order to achieve the requirements of design,the error of machine tool is analyzed at the end of this paper.