Research On Follow-up Fixture Layout Of Wing Box Thin-walled Structure In Milling

With the development of aviation manufacturing technology,thin-walled structural parts have been widely used in the aerospace field.Because most of the aviation thin-walled structural parts are made of aluminum structure,it has the advantages of light weight and high structural efficiency.Its large-scale application will effectively reduce the weight of aircraft structure and improve its structural efficiency.However,thin-walled structural parts also have problems such as low rigidity and easy deformation during processing,which in turn leads to a decline in processing accuracy and ultimately affects the production efficiency of enterprises.Based on this problem,this paper uses the wing box as the research object,and optimizes the machining process of thin-walled structural parts by constructing the milling force model and optimizing the clamping layout.The main contents are as follows :Firstly,the milling force model is constructed by using Shannon theorem.Firstly,the milling force is modeled by the Kline instantaneous stiffness model.In the practical application of the model,the upper and lower limits of the integral should be determined many times according to the angular position of different cutter teeth.Its complex and tedious application process undoubtedly increases the difficulty of constructing the multi-tooth milling force model,which in turn makes the multi-tooth milling force model difficult to perform subsequent optimization operations.In this paper,the applicability of Shannon ’s theorem to the milling force model is verified by using the Fourier formula of the single-tooth milling force model.Finally,the single-tooth milling force model is reconstructed,and the multi-tooth milling force model is further simplified.After obtaining the simplified model,the genetic algorithm is used to optimize the parameters of the simplified multi-tooth milling force model,and the multi-tooth milling force model is finally constructed with the correction function.Secondly,on the basis of completing the construction of milling force model,a new follow-up clamping layout optimization strategy for thin-walled structural parts is proposed.The optimal clamping layout varies with the size,direction and position of cutting force.The strategy is divided into two steps : 1)The frame workpiece is simplified as the deformation problem of the fixed beam and the fixed thin plate.The optimization model is established according to the elastic deformation formula and the layout scheme of the process convex is optimized.Secondly,the clamping layout optimization model for ’ thin-walled structural parts’ is established,and the maximum deformation and corresponding constraints of the workpiece at each processing position are calculated by using ABAQUS-Python secondary development,and then the optimization model is solved by genetic algorithm.Finally,the simulation test of the wing box structure is carried out.The following conclusions are drawn : 1)Shannon theorem can be used to construct the multi-tooth milling force model,and the prediction effect of the milling force model is better after introducing the correction signal;2)The genetic algorithm can complete the parameter optimization of the milling force model,and the new multi-tooth milling force model can predict the milling force and reduce the model prediction error to less than 10 %.3)The milling force model constructed by Shannon theorem can be more conveniently applied to the intelligent machining system,which provides a theoretical basis for the subsequent improvement and optimization of the intelligent system.4)The clamping layout optimization strategy of the thin-walled structural parts can obtain the clamping layout corresponding to different milling force sizes,directions and action positions,and these clamping layouts have follow-up;5)When the axial cutting depth is 1mm,the spindle speed is 800 r / min,and the feed rate is320 mm / min,the deformation distribution after the optimization of the clamping layout optimization strategy is in the range of 0.02 to 0.09 mm,which meets the accuracy requirements of part size and shape and position tolerance during finishing.Therefore,the clamping layout optimization strategy can provide a theoretical reference for the intelligent processing system.