Research On Key Technology Of Milling Simulation And Cutting Parameter Optimization Of Aluminum Alloy Conformal Parts

Aluminum alloy aircraft conformal parts are widely used in the field of aerospace because of their low specific gravity,high specific strength,conformal with the carrier without damaging the mechanical structure of the carrier.However,due to its low stiffness,thin wall,large elastic modulus and complex surface characteristics,it is difficult to achieve the ideal surface integrity requirements in milling because of the complex stress conditions,and even parts scrapping might happen in special cases.Therefore,it is of great significance and application value to study the distribution of residual stress and surface roughness in the milling process of aluminum alloy conformal parts,optimize the milling parameters,and study the detection method of surface integrity in the milling process.In this paper,5A06 aluminum alloy conformal part is taken as the research object.Based on the in-depth analysis of the three-dimensional milling mechanism of aluminum alloy,a multi-channel milling finite element simulation model is established.The distribution of machined surface roughness and residual stress of aluminum alloy conformal part is studied by using the simulation analysis method,At the same time,a method of surface integrity detection based on neural network is proposed.Finally,a prototype system of milling surface integrity optimization for aluminum alloy conformal parts is developed.The main research contents are as follows:(1)The three-dimensional finite element model of aluminum alloy conformal part multi-channel milling was built.On the basis of expounding the metal cutting mechanism and other related theories,the three-dimensional finite element model of spiral edge milling cutter and the workpiece model of 5A06 aluminum alloy are established.The surface roughness and residual stress distribution of machined surface were analyzed by using the model.It is the foundation for the optimization and research of surface integrity of aluminum alloy conformal parts.(2)Surface integrity testing method of aluminum alloy conformal parts.Surface roughness and surface residual stress are very important evaluation indexes for surface integrity of conformal parts.In this method,the time-domain and frequency-domain diagrams of cutting force and noise data in the cutting process are obtained by fast Fourier transform and wavelet packet analysis,and a multi-channel input neural network based on RESNET is constructed to obtain the mapping relationship between time-domain and frequency-domain diagrams and surface roughness and surface residual stress,The surface roughness and surface residual stress of aluminum alloy conformal parts can be detected.The experimental results show that the detection accuracy of this method is 94.97%,which has certain effectiveness and application value.(3)Milling parameters optimization based on surface integrity.Based on the finite element simulation model of conformal part milling,the mathematical model between milling parameters and surface integrity is established by using grey correlation degree and principal component analysis.Based on the mathematical model,the optimal combination of milling parameters is obtained,and the influence trend of milling parameters on surface integrity is studied.Finally,the effectiveness of the model is verified by orthogonal design experiment.(4)Development of surface integrity optimization prototype system for aluminum alloy conformal parts.Based on the above research,this paper develops a prototype system with multi-channel input neural network as the core,using Python language and pyqt.The system can build the milling finite element model through the actual tool and workpiece geometric parameters,and establish the mathematical model between milling parameters and surface roughness and surface residual stress based on the results of milling process simulation.The optimal milling parameter combination can be determined by solving the model.At the same time,the system also realizes the function of detecting the surface integrity of conformal parts according to the noise and cutting force in the milling process,which provides convenience for optimizing the surface integrity of aluminum alloy conformal parts.