Process Research On Long Shift Of Large Ratio Of Height To Diameter Boss Cold Upsetting

With a boss of the long shaft parts is one of the most common mechanical parts.Currently, the processing method of the kind of parts was often used cold upsetting,not only to meet the needs of mass production, but also to ensure dense organizationof the parts, to continue metal flow line and to improve the mechanical properties.However, long shaft parts with large ratio of height to diameter boss was used coldupsetting, the ratio of height to diameter was often greater than the unstable limit andupsetting instability. Thus, the urgent need to solve the problem of large ratio ofheight to diameter boss in the process of cold upsetting was how to reduce the ratioof the height to diameter.Large ratio of height to diameter boss appeared the plastic instability easily inthe process of forming, the effects of the boss forming process parameters wasdetermined, with the use of the theory of metal principal stress method to analyze it.With C100motorcycle engine spindle as the research object, the scheme was workedout which was the necking and cold upsetting, with the help of plastic finite elementsoftware were DEFORM-3D and simulated boss forming process, the influence lawof process parameters on forming was obtained. Based on the process test of theresults of the numerical simulation, the boss which necking firstly and cold upsettingfinally was satisfaction, met the design of requirements and would be the guidanceof production practice.Aiming at necking+cold upsetting defects of forming process, the new schemewas proposed which gathering material+cold upsetting. Using a combination ofexperimental design and numerical simulation methods, the boss forming qualityprediction formula was derived. The single cone die gathering material+coldupsetting forming limit was given from applying of compressive bar plastic bucklingtheory, with the help of DEFORM-3D numerical simulation of single gatheringmaterial+cold upsetting process, numerical simulation and theoretical derivationconsistency, as the basis for the C100engine spindle boss was proposed a singlegathering material+cold upsetting solution.The feasibility of double die gathering material+cold upsetting formingprocess was preliminary explored, with the help of using a combination ofexperimental design and numerical simulation methods, obtained that the influence of process parameters of the scheme and to lay the foundation for further in-depthresearch.