Study Of Springback Model Construction And Springback Compensation Of Die-less Spinning

Spinning is a kind of metal plastic forming technology,which is widely used in aerospace field,weapon production,civilian industry and so on.Due to the limit of general spinning's relying on mandrel with specific shape and the growing demand of product diversification,die-less spinning has become a hot research topic with broad market prospect.The related researches mainly focus on forming method,basic mechanism and finite element simulation model.However,springback,as the main source of the quality problem of die-less spinning,only accounts for a minority of the researches.In this paper,the springback models of parts with cone shape and curvilinear generatrix are established.Based on the springback models,springback compensation is also accomplished.Based on the FEA analyzation platform ANSYS/LS-DYNA,the simulation model of forming and springback process of die-less spinning is built.Through observing the situations of three pairs of stresses,the free deformation mechanism and springback mechanism of die-less spinning are analyzed,which is the basis of the construction of springback model and the study of springback compensation method.Springback model of single-pass die-less spinning of cone parts is built,which is the basis of effective springback compensation.With the method of analyzing the springback influence factors of single-pass die-less spinning of cone parts,target deflection angle and the feed ratio are selected to build the springback model.Angle expression method is chosen as the springback amount parameter.Feed ratio coefficient is proposed to build the integrated springback model of cone parts' single-pass die-less spinning,which can be used to compensate the springback error.Springback model of multi-pass die-less spinning of cone parts is established with proposing the concept of equivalent target deflection angle of previous-passes.Target deflection angles of the final pass and the whole previous pass,number of the passes,processing amount allocation situation of each former pass and feed ratio of the final pass are picked to be the main influence factor of this springback model.By simplifying the multi-pass die-less spinning into two-pass,the springback model on final pass deflection angle and the whole previous pass deflection angle is established.The equivalent previous pass deflection angle is to restore the springback influence of the former passes' situation,which is ignored in the process of simplification.Likewise to the single-pass model,after adding the feed ratio coefficient,the springback model of multi-pass die-less spinning of cone parts is finally established.Then,springback compensation under certain conditions can be realized.Springback model of die-less spinning of curved generatrix parts is constructed with three sections to achieve the divide-and-conquer compensation of the springback.In order to research the springback situation more convenient,key points are collected according to the characteristics of the generatrix shape so that the simplified model of the curved generatrix is acquired.Based on the established springback model of cone parts'die-less spinning,curved generatrix parts' springback model is divided into overall springback model and local springback model.Furthermore,local springback has two important sections:one is the influence of local shape of forming segment relative to the tendency of the whole shape of curved generatrix,the other one is the influence of the shape of forming segment's near district.On the basis of different springback resource to use the springback model,divide-and conquer of the springbach compensation can be achieved.