| More and more countries have regarded the aviation industry which is an important manifestation of a country’s comprehensive strength and scientific and technological strength as their pillar industry.As a power source for the development of the aviation industry,the machining quality of aeroengines parts directly affects the power performance of aircraft engine.As one of the core components of aviation,the processing quality of the fuel nozzle has an important impact on the fuel combustion efficiency of the aircraft engine,thus it is an important way to improve the power of aero-engines by improving the machining quality of the fuel nozzles.In this paper,the nozzle hole which is difficult-to machine part of the aero engine has been taken as the research object.Special profiling drills have been designed by formulating the nozzle machining route to study the machining plan of nozzle hole.A finite element simulation model of a selected special drill’s drilling process has been established,and the influence of drilling parameters on drilling performance has been analyzed and the reliability of the simulation model was verified by drilling experiments.Taking the drilling temperature,force and torque as the combined targets,a predictive model of the relationship between drilling parameters and target response was established.The optimized combination of drilling parameters was obtained based on the multi-objective particle swarm optimization(MOPSO)algorithm,and the optimization results have been verified through experiments.The research contents of this paper mainly included:(1)A nozzle hole machining plan has been developed for a certain type of fuel nozzle and the structural features of the tool was designed according to the micro-hole characteristics.For the selection of tool material,it was determined by the cutting cost and cutting performance which was studied by establishing different tool materials finite element simulation models.(2)A designed solid carbide profiling drill was selected as the research object.The effects of drilling parameters(spindle speed and feed rate)on drilling performance(drilling temperature,force and torque)have been studied based on the results of finite element simulation experiments.The results demonstrates that the increase of spindle speed will cause the increase of drilling temperature,and feed rate is the main factor that affects the drilling force and torque.In addition,the drilling force collected in drilling process has been compared with simulation drilling force,it was found that the error did not exceed 10%,which has verified the reliability of the finite element simulation model.(3)The relation model between drilling parameters(spindle speed and feed rate)and drilling performance(temperature,force and torque)was established based on response surface method(RSM)regression analysis and support vector machine(SVM).It turns out that the SVM model has better fitting performance and generalization ability in comparison.(4)Based on the establishment of the prediction model,taking the drilling temperature,force and torque as the combined targets,the multi-objective particle swarm optimization(MOPSO)algorithm was used to find out the drilling parameters with lower temperature,force and torque.The optimized drilling parameters were verified through finite element simulation experiments and actual machining experiments.The experimental results showed that the drilling force has been smaller,the tool wear rate has been slowed and the surface quality of nozzle hole has been improved when the optimized parameters were used for drilling. |
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