Research On The Compensation Die Desgin And Forming Tests For Rubber Bladder "One Step" Process

Rubber bladder “one step” process has gained recognition in production and certainapplications due to the following advantages such as good quality of forming surface, highworking efficiency, reduced manual labor intensity at the same time etc. But thecharacteristics of “one step” process don’t allow a lot of artificial knock during repair thatmakes the springback and wrinkling of parts after forming the main reasons of its limitedpopularization. In order to solve the compensation “one step” process die design and lowforming efficiency, in-depth research has been carried out on the key technology of aircraftsheet metal rubber bladder precision forming in as-quenched state.In this paper, mechanical properties and formability parameters at the conditions ofdifferent aging time in as-quenched state of2024and2A12aluminum alloys, which arecommonly used in aircraft, are obtained from a tensile strength test. Straight and curvedflanging die design for rubber bladder forming in as-quenched state and the correspondingorthogonal and forming experiments are completed. It is concluded that the different factorson the influence of straight and curved flanging forming quality, minimum bending radius, aregiven. Springback value of2024and2A12under different conditions in as-quenched statewas studied, springback ranges of different conditions are given.Several kinds of typical aircraft sheet metal parts were adopted in finite elementsimulation of rubber bladder “one step” forming. Its forming characteristics are discussed, andspringback distributions of typical parts are studied. Suggestions in solve warping andspringback problems in forming process are given at last. Using acquired die working surfacecompensation algorithm completed compensation die design. Using finite element formingsimulation compared the springback value before and after compensation, and the conclusionof the forecast is given.Compensation dies of typical parts were made, and using confirmatory forming testvertified the validity of compensation die, found that the error between die and formed part isin good condition, and through this method, solved the difficult problems of aircraft sheet metal precision forming in as-quenched state, enlarging the scope of the rubber bladder “onestep” forming process.