Research On Mechanism And Control Of Flatness Defects For Wide Aluminum Foil Strip

The wide aluminum foil strips have a very large width-to-thickness ratio,which leads to longitudinal flatness defects in rolling production and transverse flatness defects in the coiling process of the cleaning line after rolling.The generation mechanism of the flatness defects is complex,and there are many influencing factors,which will reduce the production efficiency and increase the amount of waste,while the relevant research is still insufficient.The mechanism of longitudinal flatness defects of aluminum foil strip in the rolling process and transverse flatness defects in the cleaning and coiling process is still not clear,and effective control methods are lacking.Relying on the foil rolling unit and the cleaning coiling unit of an electronic aluminum foil factory,this paper aims to improve the flatness of the aluminum foil strip.An analytical model of longitudinal local buckling and an analytical model of transverse buckling of aluminum foil strips were established respectively,and the control of the longitudinal edge-ribs waves and aluminum foil transverse flatness defects were studied.The main results are as follows:(1)Based on the symplectic elasticity method,an analytical model of the longitudinal local buckling of the wide aluminum foil strip is established,which avoids the error caused by the assumed deflection distribution function when solving the buckling by the energy method,and improves the accuracy and calculation efficiency of aluminum foil strip longitudinal local buckling.This model is used to study the influence of size and boundary constraint conditions of buckling area on the longitudinal local buckling.The results show that the boundary conditions of buckling area will significantly affect the buckling deflection distribution,which further verifies the insufficient of assuming the same deflection distribution function for different boundary conditions when the energy method is used to solve buckling.(2)Aiming at the problem of longitudinal edge-ribs waves in the wide aluminum foil rolling process,a locally convex work roll contour with multi-segment curve was designed.The work roll contour parameters can be optimized by the actual aluminum foil strip flatness defects,work roll and aluminum foil cross-sectional,which is highly adaptable.The simulation model is used to study the flatness control characteristics of the new work roll contour,and the results are verified by the rolling experiments,which show that the new work roll contour can increase the reduction of aluminum foil strip edge and improve the aluminum foil flatness.(3)Aiming at the transverse flatness defects of wide aluminum foil during the coiling process of the cleaning line,a dynamic simulation model of the aluminum foil coiling process was established and the development law of transverse flatness defects of aluminum foil was obtained.After introducing the evaluation index of flatness defects,the influence law of multiple factors in three aspects:the coiling process,coiling equipment and the aluminum foil initial shape on the transverse flatness defects is quantitatively analyzed,and the corresponding improvement measures are proposed.Taking the longitudinal stress of aluminum foil obtained by the coiling simulation model as the boundary load,an analytical model of aluminum foil strip internal stress is established based on the symplectic elasticity method,which can avoid the error caused by the pre-assumed stress distribution function in the semi-inverse solution method,and improves the stress solution accuracy.On this basis,the Galerkin method is used to analyze the transverse buckling of aluminum foil,and the results are in good agreement with the actual production situation.The coiling test results show that the buckling analysis method and related simulation work are beneficial to improve the transverse flatness of aluminum foil during the coiling process.