| Aluminum alloy has high strength and rigidity,good corrosion resistance and excellent fatigue strength.The thin-walled parts of aviation aluminum alloy provide the possibility of lightweight and excellent performance for equipment,which are widely used in aerospace manufacturing industry,and the research of its machining property is a common subject in the manufacturing industry.Most of the machining methods for aviation thin-walled parts are milling,which requires high precision,high efficiency and high performance,but the characteristics of thin wall thickness,low rigidity,complex structure and compactness have caused poor processability,and it is difficult to ensure the accuracy and quality of processing.In this paper,considering the actual machining conditions,the prediction model of cutting force and machining deformation is established by using the finite element analysis technology,which can analyze the milling process of thin-walled parts more comprehensively and obtain the results that are difficult to obtain in machining.In this paper,the basic knowledge of finite element is introduced firstly,and three kinds of software "Deform","AdvantedEdge" and "ABAQUS" are commonly used in cutting simulation.Some finite element principles,such as iteration method,application method and application scope,are explained in detail.Combined with simulation examples,the advantages and disadvantages of the three software are summarized,and the application performance is compared.The ABAQUS software is adapted to build the 3D milling simulation model,and the key parameters and steps involved in the modeling process are described in detail.In this paper,the three-dimensional modeling of the whole end milling cutter is carried out,and the hypocycloid trace of the real milling cutter is used for the geometric modeling of the workpiece,which not only saves the simulation time,but also makes the established model fully close to the real machining condition.Using the function of creating quick plug-in embedded in ABAQUS,the 3D milling simulation modeling process is encapsulated into kernel file,and 2D and 3D cutting simulation plug-ins are created.The 3D milling finite element simulation model of Al7050 is established and solved.According to the simulation results,the Mises stress distribution and chip shape during the cutting process are analyzed in detail.The multi factor experiment table was designed to carry out 54 groups of milling experiments of al7050,and the experimental data of three-dimensional milling force were obtained.According to the "quasi horizontal" method,the orthogonal table is extracted from the experimental data and the range processing is carried out.The conclusion is that in the cutting parameters,the axial cutting depth has the greatest impact on the cutting force,and the spindle speed has the least impact on it.Secondly,the cutting force in the experiment is greatly influenced by the tool eccentricity and vibration,while the existing mathematical model of cutting force is difficult to establish a complex milling force model,and there are complex and tedious calculation steps.Therefore,based on the cutting force measured in different machining parameters in the milling experiment,the finite element analysis(FEA)method,genetic algorithm optimization the back propagation neural network(GA-BP)and the particle swarm optimization neural network(PSO-BP)are used to effectively establish the milling force prediction model.The results show that the models established by ANN can effectively and accurately predict the dynamic milling force,but the PSO-BP model has the highest prediction accuracy.The process parameters,such as stress distribution,temperature distribution and chip formation,which are difficult to obtain by experiments,can be obtained by finite element simulation.According to the element life and death technology,the machining deformation simulation of the ribbed channel structural parts is performed to simulate the material removal process.The tool path trajectories of nine machining paths were calculated using Matlab programming,and the overall machining deformation simulation model was established using the INP file.After processing the deformation of thin-walled parts with different processing paths,the contour map of machining deformation can be drawn through data processing.The deformation rules and optimal processing paths of thin-walled parts under different machining paths are summarized and summarized,which is of guiding significance for production practice. |
