EVOLUTION MECHANISM AND CONTROL STRATEGY OF WORKPIECE MACHINING DEFORMATION IN BLANK SLOTTING METHOD

Residual stresses can be generated in aluminum alloy thick plates used widely as the blank of aeronautical thin-walled monolithic components because of the non-homogeneity of plastic deformation induced in the blank manufacturing process. The release of residual stress in high-speed milling process causes the machining deformation of aeronautical thin-walled monolithic component which can severely influence its machining quality. Therefore, the finite element simulation method of milling process is established for the thin-walled workpiece in the deformation-released blank. The finite element simulation values, as well as the calculation values obtained by the deflection analytical method, are verified to be highly agreed with the experimental measurement results in both trend and magnitude. The influence of slotting mode on the blank releasing deformation is revealed by the finite element method so that the relationship between the blank releasing deformation and the workpiece machining deformation is obtained. The result shows that the reduced workpiece machining deformation is the same as the blank releasing deformation. Based on the prediction model of blank releasing deformation, a genetic algorithm optimization method is proposed for the blank slotting mode. The random test set shows that the prediction accuracy of the neural network is about as high as 95% whereas the machining deformation of the three-frame workpiece can be reduced by 34.5% in the optimal slotting mode.