Research On Near-net-shape Technology For Large-angle Skins

With the improvement of the technical and tactical indexes of the cruise missile,the fuel loading rate is higher and the weight of the whole missile is lighter and lighter,which makes the shape of the missile transition from regular circle to free-form surface.As the shape of missile skin,the area of skin parts is larger and larger,and the shape is more complex.The existing process scheme cannot meet the equipment requirements.In this paper,we try to find a fast,efficient and low-cost manufacturing method for such large angle skin parts through experiments.The large angle skin in this project gives up the traditional chemical milling and "forming first and reducing weight" which are complex and inefficient,and adopts the processing route of "weight reduction first forming then trimming".The specific methods are as follows:(1)The position of neutral layer of integral panel with grid stiffeners is obtained by theoretical calculation.On this basis,based on the commands of "offset face"," trim sheet"," flatten and form" and "edge rounding" in UG modeling module,the flattened large angle skin design model is obtained.The bottom locking structure and sealing boss are designed for the subsequent superplastic forming process.(2)Based on the NC programming module of UG software,the efficient and no over cutting tool path of sheet metal skin weight reduction and skin hot forming is programmed.(3)The model of machine is established in VERICUT,and various parameters are configured for the tool,and the fixture,blank and workpiece are imported.The NC code is verified by simulation.Ensure that the program has no over cutting and residual,and realize the simulation of real machining environment.(4)Based on VERICUT program optimization module,the roughing program of sheet metal skin is optimized,which can reduce duration of rough machining,improve the processing efficiency and prolong the tool life.From these research,the large angle skin is successfully processed,and the parts are processed with high efficiency and low cost.It is proved that this process is suitable for the similar large angle skin products.