Milling Deformation Mechanism And Deformation Prediction Of Aluminum Alloy Large Thin Arc Plate

As one of the representative achievements of China's aerospace industry,long march series launch vehicles have good prospects for development and strategic significance of The technology powers.The tank is the key part to determine the shape and orbit precision of the rocket.In order to reduce the weight,hundreds of grid structures need to be milled on the inner side of the tank.However,because the panel has a certain degree of arc,large size,high area to wall thickness ratio,it is easy to deform during milling,resulting in the reduction of machining accuracy.Therefore,it is of great significance to study the milling deformation mechanism of aluminum alloy large and thin arc plate for realizing the active control of machining deformation and improving the machining quality and efficiency of workpiece.In this paper,large thin arc plate of aluminum alloy 2219 is taken as the research object.Firstly,based on the differential thought and double acting mechanism,the mechanical behavior of 2219 large thin arc plate is clarified,and the milling force model of large thin arc plate processed by two edge fillet end mill is established.The validity of the model is verified by experiments.With the aid of the finite element analysis software ABAQUS,a three-dimensional simulation model under the action of thermal coupling is established.The model can show the change of milling force load in a small error range,which lays a foundation for the study of the deformation behavior of the thin arc plate under the action of multiple factor couplingThe mechanism of residual stress in milling of large and thin arc plate is analyzed from multiple points of view.Based on the four factors and four levels orthogonal experiment of single mesh milling,the distribution of residual stress on the grid surface after milling is obtained by X-ray measuring instrument.Thus,and the influence of milling process parameters on the stress evolution of the milling surface of large and thin arc plate is revealed.The high speed and low feed machining method is conducive to the low surface stress state in machining process.The distribution state of the initial residual stress in the large and thin arc plate is defined,and the deformation behavior of the large and thin arc plate under the action of the two directions initial residual stress is studied.On the basis of solving the key technology of finite element simulation,the cutting load is transformed according to the milling force results obtained from the milling force model,and the mesh is divided based on the milling parameters.A three-dimensional finite element simulation model of large and thin arc plate mesh milling deformation is established under the action of multiple factor coupling.In this paper,the influence of the mesh processing sequence on the milling deformation is studied,and the optimal milling process is proposed.According to the deformation of single grid milling experiment obtained by three coordinate measuring machine,the processing deformation law of large and thin arc plate is analyzed.The maximum deformation of thin arc plate is taken as the evaluation object,and the gain relationship between cutting process parameters and workpiece processing deformation is established.The main factors that affect the deformation of the thin arc plate are determined,which provides a method for the active control of the machining deformation and proves the correctness of the finite element model.Based on the results of orthogonal test,the prediction model of machining deformation of large and thin arc plate parts is established by using the polynomial curve fitting principle.The model can predict the maximum deformation of thin arc plate when milling the grid under the condition of relatively error.