Study On Forming Quality Of Multi-pass Spinning Of Thin-walled Curvilinear Generatrix Parts

With the nonlinearities of geometry,material and complex boundary conditions,multi-pass spinning is affected by coupling effects of multiple factors,such as roller path,process parameters,etc.And with the characteristics of the high diameter-thickness ratio and depth-diameter ratio for thin-walled curvilinear generatrix parts,the forming quality control was rather difficult.The defects of cracking,wrinkling and over-thinning were prone to happen during the spinning process.Therefore,forming quality problems need to be studied.This paper studies the finite element modeling method of multi-pass spinning,a parameterized method of roller path design for multi-pass spinning has been proposed.The mapping relationship between the process parameters and the forming quality of spinning parts is studied.Based on the constant processing time condition,the control strategies of the variable roller feed ratio considering the bending effect and the thinning effect were studied.The geometric profile design methods of variable thickness blank were put forward for the conventional spinning and shear spinning.The details are as follows:1)Based on the ABAQUS/Explicit platform,the key technologies of the finite element simulation modeling for multi-pass spinning,including meshing control,setting up of analysis steps and boundary conditions and so on were studied,and the evaluation index of forming quality for multi-pass spinning was determined.2)Roller paths of multi-pass conventional spinning are rather complex,with great uncertainty,depend heavily on craft and experience.In this paper,a parametric roller path design method which could flexibly set the mode of starting point allocation,roller path profiles,backward pass strategy,the roller gap was proposed and used to perform spinning experiments and to conduct finite element simulation analysis.3)The influence of each process parameter on the forming quality was studied by using the single variable method.The key process parameters and the reasonable range of the process were obtained.Variable roller feed ratio strategies was proposed considering the bending effect and the thinning effect,the impacts of the variable feed ratio strategies on the forming accuracy of spinning process were explored.4)Based on the studies on trajectory planning and process parameters,the geometrical mapping relationship between the initial blank and the final spinning part was studied.With the uniform thickness spinning part as the final forming target,based on the method of reverse deformation,geometric profile design methods for the conventional spinning and shear spinning were proposed.The result shows that variable thickness blank can significantly improve the forming quality of the forming parts.