Modeling Of Machining Errors Of Thin-walled Parts Based On Iterative Calculation Of Cutting Thickness

The demand for thin-walled parts of titanium alloy in the aviation field is increasing,because it can meet the requirements of high strength,high rigidity and high fatigue resistance of aviation parts.Due to the large amount of metal removal during the processing of thin-walled parts,the milling force and workpiece deformation will cause the decrease in machining dimensional accuracy.If processing errors rely solely on experimental methods to study,it not only will make the experimental process burdensome,but also will increase the experimental cost and the experimental cycle.Based on the above issues,this paper conducts theoretical and experimental research on the machining errors generated during the milling of thin-walled parts of titanium alloy.The main research contents are as follows:Firstly,during the side milling process of thin-walled parts,the material removal is large,the tool rigidity is greater than the workpiece stiffness,and machining deformation is easy to occur.The cutting force model of the sidemilling of thin-walled parts is improved by introducing the processing deformation.According to the coupling relationship between cutting force and deformation during milling of thin-walled parts,a milling force prediction model for thinwalled parts is established.The relationship between the deformation of the workpiece system caused by the milling force and the feedback of the deformation system to the milling force is considered in the model.Secondly,based on the deformation mechanism of thin-walled parts,the bending deformation model of thin-walled parts during milling is established;the precise geometric model and boundary judgment conditions of the cutting contact area between the tool and the workpiece are established through different basic cutting parameters;The discrimination relationship between single-flute cutting and double-flute cutting is established;the instantaneous cutting thickness is recalculated by introducing the workpiece deformation.After carrying out cutting experiment,simulation results are compared with the experimental results to verify their validity.Then,based on the workpiece surface contour generation mechanism and the obtained workpiece system variable matrix,the thin-walled parts machining error modeling is performed to predict the machining error generated during the side milling process.Through actual cutting experiments,the experimental results are compared with the results of the numerical simulation model.As a result,the prediction model in this paper can effectively predict the processing errors of thinwalled parts.Finally,based on Matlab,a simulation prediction platform for milling errors of thin-walled parts is developed.The system simplifies the operational steps of the simulation process.By establishing the relationship between force and deformation during milling of thin-walled parts,the machining error caused by deformation is predicted.This model improves the efficiency of prediction of machining errors,and provide a theoretical basis on optimizing the process and tooling road compensation.