Research On Simulation And Control Technology Of Machining Deformation For Thin-wall Rotary Parts

In aerospace,automotive and other fields,aluminum alloy thin-walled parts are widely used because of their features of light weight and compact structure.However,due to the low stiffness,and the coupling of various factors in the cutting process,the machining deformation of this type of part is difficult to control.Among all the factors that affect the machining deformation of thin-walled parts,the release and redistribution of bulk residual stress,the influence of cutting load and the machining-induced residual stress are the main factors.In this paper,through finite element simulation and theoretical analysis,the effects of the above three factors on the machining deformation and the control technology of machining deformation for thin-walled rotary parts are studied.The main research contents are as follows:A three-dimensional oblique cutting model is established to simulate the cutting process of 2024 aluminum alloy.The shape of the chip and the stress and strain state of the machining area are analyzed.At the same time,the cutting force and heat during cutting and the residual stress on the surface layer after cutting are extracted.By comparing with the existing literature,the correctness of the cutting model is analyzed and verified.The effects of bulk residual stress and machining-induced residual stress on the machining deformation of the workpiece are studied.The mechanism of machining deformation under the influence of two types of residual stress are analyzed.Futhermore,two calculation examples are designed,and finite element software is used to simulate the machining deformation under the influence of two types of residual stress.The effects of two types of residual stress on the machining deformation of workpieces under different wall thicknesses are compared and analyzed.The results showed that the machining deformation is mainly affected by bulk residual stress,and in the finishing stage,both the bulk residual stress and the machining-induced residual stress have important effects on machining deformation of the workpiece.A prediction model of machining deformation under the coupling of cutting force,cutting heat and bulk residual stress is established.During the model building process,the key technologies were studied,such as the material removal and definition of analysis steps,load application,and application of secondary development technology.Through the established prediction model,the machining process of the workpiece is simulated.Futhermore,the stressand temperature distribution inside the workpiece during the machining process,and the deformation of the workpiece after the processing are analyzed.The analyses showed that the established prediction model conforms to the actual processing situation.Through the established prediction model,the machining deformation of the workpiece affected by two kinds of machining craft are studied.One is to relieve stress before machining,and the other is to change the number of cutting.The results showed that before cutting,the residual stress relief can significantly reduce the deformation of the workpiece.Compared with the once cutting,the cutting with twice increases the deformation of the workpiece caused by the cutting heat.