Study Of Die-Closing Method On Hydroforming Large Size Circular Component

In recent years,the hydro-forming technology develop rapidly.The hydro-forming components with strength,low quality and low cost advantage compared with other forming mode.Especially tube hydro-forming wide used in the field of aerospace,nuclear and automobile.The study of this paper is based on the forming experiment of a large circular component.In this paper,the shape of the large circular component is more complicated and the size is larger.In the process of hydraulic forming,there is a high demand not only for the hydraulic forming process,but also for the die locking problem.Press on the market at present is mainly used to as a forming die clamping device,but press working mesa dimension fixed,for some of the larger size of die,wanted to impose uniform clamping force has its difficulties.In this paper,we study the locking problem of the hydraulic forming process of the largesized circular components.A numerical simulation method is used to analyze the two modes of press locking and bolt mechanical locking.It is found that when the size of the component is too large,it is difficult to select the pressure machine which is suitable for the clamping pressure and working mesa size.And the simulation results show that when the working table size is less than the projected area of the molds,even if the clamping force of the press is large enough,it still can't guarantee the dimension accuracy of the components after forming.The bolt mechanical locking mode is adopted to optimize the bolt's diameter and the number of bolts,which can finally realize enough locking pressure and uniform force of the die components.Then a large hydraulic forming die based on bolt mechanical locking mode has been developed and tested.Results also confirmed that the bolt mechanical clamping way safe and reliable,and for hydroforming of big size and small batch components effect is excellent,the dimensions of the formed components precision can meet the design requirements.But bolt mechanical clamping way of clamping end of efficiency exist problems,so in order to better future for mass production in the factory,on the basis of front research and design a set of clamping device,through the simulation results show that this device cannot only realize the request of clamping can also achieve change die clamping force of the loading process,not only can greatly improve the efficiency of forming can effectively protect the mold,extend die use fixed number of year.