Research On Trepanning ECM Of Diffuser With Special Structure

As a key component of a aero-engine,the performance of a diffuser directly affects the service life of the aero-engine.Electrochemical machining(ECM)has become a core manufacturing technology of diffuser because of no tool loss,low cost in mass production,and it’s suitable for different-to-cut materials.In this paper,the research on the trepanning ECM of the diffuser is carried out.Specific work was performed as follows:(1)According to the diffuser of special structure,the method of the trepanning ECM was selected,and the corresponding flow field was designed.The flow field simulation and optimization analysis were carried out.The results showed that the uniformity of the outlet-corner flow field is better than the uniformity of outlet-open flow field,when the outlet gap is 0.35 mm and corner gap is 0.30 mm,the uniformity of flow field is best.According to the optimized flow field,the sealed fixture was designed,the comparative experiments of jacketed ECM were carried out.The results showed that,under the condition of optimized flow field,the machining process was stable,and the feed speed of cathode had reached 0.5 mm/min.(2)The research of variable voltage to decrease the taper of blade was carried out.The mathematical model for decreasing the taper of blade was established,and the variable voltage taper reduction experiment was carried out.The experimental results show that the tangent value of the blade taper is reduced from 0.071 to 0.006 when the processing voltage varies from 15 V to 19.02 V.(3)The research of cathode correction by equal proportion adjusting of the allowance error was carried out.The mathematical model of cathode correction was established,and the cathode correction experiment was carried out.The experimental results show that the single side allowance of blade: 0.43-0.48 mm on left side;0.38-0.43 mm on right side;0.46-0.52 mm on leading edge by using the method of cathode correction by equal proportion adjusting of the allowance error.(4)Application research of the trepanning ECM was carried out for a aero engine diffuser.The process parameters were optimized,and a sector of the diffuser was manufactured.After measuring,the single side of blade: 0.45-0.49 mm on left side;0.37-0.46 mm on right side;0.48-0.54 mm on leading edge,the repeatability precision is 0.072 mm and the processing time of a blade is 13.33 min.