Simulation And Experimental Analysis Of Dynamic Characteristics In Milling Process For Aeronautical Thin-wall Parts

6061T6 is a precipitation hardening type aluminum alloy,which is widely used in aviation,aerospace,automotive and other fields.Presently,aluminum alloy materials mainly appear in the form of thin-walled parts and large-scale structural parts in aerospace industry.However,the manufacturing level and processing technology of such parts are not different from those of developed countries in the West.However,the manufacturing level and processing technology of such parts are far from the developed countries in the West.For the problem of poor rigidity of thin-wall part of aluminium alloy and the difficulty in controlling the machining accuracy,based on the research of milling force,the processing characteristics of force,flutter,deformation and tool wear were conducted in-depth research.Based on the kinetic model,the flutter stability prediction model and the machining surface elastic deformation model is established,and the tool wear amount recognition model is considered.At the same time,the research method of combining theory and experiment were adopted,and the accuracy of the theoretical model is verified by milling force experiments,modal experiments,elastic deformation experiments,and tool wear experiments,and the machining parameters are optimized reasonably such as radial depth of cut,axial depth of cut,feed rate and spindle speed.The main research contents include:It is difficult to accurately predict the instantaneous milling force during the side milling process,the vibration and noise of the machine will increase the amplitude of the average milling force.For these problems,in this paper,a wavelet double threshold denoising method based on inter-layer correlation coefficient is combined to obtain accurate instantaneous milling force signal.Furthermore,the basic idea of micro-milling force is adopted,and the milling force prediction model of side milling is established.Then the influence of each parameter on the milling force is verified through simulation.The accuracy of the flutter stability prediction model of the zero-order frequency domain method is imprecise,and the calculation speed of multi-frequency method,is slow.Faced with these issues,and based on the mechanism of flutter generation,the dynamic model is improved.This method combines the Floquet system stability theory,the influence of tool-workpiece modal parameters on machining stability were taken into account,then a semi-analytical prediction model of flutter stability based on the third-order Long Gokuta method is established.At last,the processing parameters were optimized.It is easy to produce elastic deformation for the clamping form of the tool and the workpiece during the side milling process,the effect of "lacking of milling phenonmenon" on the machining accuracy caused by the elastic deformation of the tool and the workpiece is fully considered,the theory of thin plate elastic deformation were introduced into the milling process.Through simulation and experimental research,the influence of machining parameters on the elastic deformation of the workpiece is explored and optimized.Aiming at the wear and the chips stick to the tool in the machining process,and to prevent the impact on the machining accuracy.Based on the dynamic model,the coefficients are recalibrated and the time domain features of the wear tool and the wavelet multi-scale features are extracted.At last,the feasibility and effectiveness of the tool wear identification method are verified by experiments.