Study On The Forming Force Prediction Of Single Point Incremental Forming Process

Single point incremental forming process(SPIF)has high flexibility and could improve the formability of metal sheets.It is one of the hot research topics of sheet forming technology.In SPIF process,a forming tool which is controlled by the reasonable trajectory presses metal sheet and realize the plastic deformation gradually.The accumulation of the local plastic deformation obtains the desired shaped finally.The forming tool is under the deformation resistance of sheet and the friction between the tool and sheet.The axial forming force on the tool will be an important basis of the equipment design and the part selection.The calculation of the deformation resistance is very complex and the local temperature rise caused by friction will affect the mechanical properties of material,which will the challenges to predict the forming force accurately.This paper focuses on the axial force prediction of SPIF.Preliminary SPIF experiments are carried.According to the local temperature rise caused by the friction between forming tool and sheet,warm and hightemperature mechanical properties of AA5754-O aluminum alloy were studied and a thermo-mechanical coupling finite element model was studied to find a predicting formula of axial forming force.The main work of this paper are as follows:1.Set up a SPIF equipment and a measurement system to carry out the preliminary experiments of a cross cone part and analyze the changing of axial force and local temperature during the processes.2.Study the mechanical properties of AA5754-O in warm temperature and establish the constitutive equation of AA5754-O in range from room temperature to 200 ?.Realize the application of this constitutive equation in simulation by Abaqus User Subroutine.In addition,a preliminary study of the superplastic behavior of AA5754-O at high temperature was conducted to research on the influence of temperature and strain rate on mechanical properties.3.Based on the Abaqus/explicit,a thermos-mechanical coupling finite element model is set up to analyze the deformation characteristics of material after forming and the local deformation characteristics of the contact area between forming tool and sheet during forming.4.The influence factors of the axial forming force on the equipment during the incremental forming process are analyzed by the finite element model.According to the results of FE simulations,a new axial forming force predicting formula which considers the influence of the spindle speed on the axial force is obtained by modifying the existing predicting formula.