Research On Precision Modeling Of Milling Force And Surface Error Prediction Based On "S" Part

With the rapid development of aerospace technology,in order to improve the mobility of the aircraft,a large number of aluminum alloy thin-walled structures are employed to reduce vehicle weight.Due to the characteritics of thin-walled structures with complex shape,stiffness and large amount of material remocal,etc,and the large surface error consists of the deflections of tool and part in milling,lead to bad milling quality,it is a difficult complex manufacturing process problem recognized internationally.“S” part is an international standard specimen put forward by Chengdu aircraft industry group after years of research experience and related theoretical knowledge accumulation,better than the American “NAS” part to test Comprehensive precision of five-axis CNC machine,which has the characteristic of variable curvature and open and close angle conversion.,can test the precision of CNC machine more totally,and conduce to the ability of independent research and development for domestic CNC machine.Used the milling simulation software Advant Edge to study the independent influence of diffirent parameters,and design an orthogonal simulation plan,constructed and solved an exponential empirical of the milling force prediction model fit to aluminum alloy 7075-T7451.Analyzed the milling force distribution of “S” part,and verified this milling force model with comparation to the result of analys of FEM simulation software.Calculated the surface error of “S” part under the empirical milling force model,and studyed the material removal rate,and finished the optimization of milling parameters on condition of both taking milling precision and milling efficency into consideration.Constructed three dimension precise milling force prediction model based on the micro element method according to the research of milling theory and the thought of milling force coefficient calibration.Analized and processed the force data of the micro elements by the simulation analys software AdvantEdge,re-calibrated the unit milling force coefficient,Studyed the contact pair between the tool and workpiece,resreached the solution of contact line equation,and the establishment of precise milling thickness model,researched the state of single blade cutting and multi blade cutting,establisd a discrete model along the axis of end mill tool and made a vector overlapped,provided a three dimension precise milling force model with the milling central angle as independent variables,verified the accuracy of the milling force prediction model by milling experiments.Solved the elastic deflection of “S” part for diffirent milling position based on the precise miling force prediction model,according to the theory of interaction between tool and workpiece,and combined the tool deflection,acquired the surface error in emulational milling.Mathematic iteration used surface error as feedback was employed in the study of tool path for “S” part in milling,established the theoretical compensation model with Matlab,realized the machining path optimization,improved the surface machining accuracy of “S” part.