Shock Sheet Metal Incremental Forming Mechanism And Experimental Study

Traditional stamping mould is applied widely in industrial production,owing to its high forming precision, low cost, high material utilization rate. With the development of product diversification,It is serious challenges for traditional stamping mould to get by, because of mass production. Such as design, manufacturing and commissioning period of mould is long, the manufacturing cost is high, especially to middle or small batch productionof sheet stamping forming, the cost of single stampings is always high.To meet the fast and flexible forming of sheet, the incremental impact forming of the sheet metal is put forward for the first time. Local plastic deformation of sheet metal can be caused by little impact kinetic energy.the incremental impact deformation way of sheet metal is that a number of small local deformation can be produced through high-frequency impact, then these small local deformation would create three-dimensional forming surface by incremental way.Impact forming of sheet metal does not require custom templates or support agencies, three-dimensional model of panel can be created using the3D modeling system, analyzed data of three-dimensional model and then generated the NC program automatically.With the NC program the movement of the impact rod and sheet metal installation platforms can be controled.On the basis of the original energy method,this paper analysised the deformation process of metal sheet and put forward a expression that can describe the relationship between vertical displacement of Sheet metal and radius. Through the theoretical analysis, the relationship of impact velocity,impact energy, mterial performance and sheet thickness with the sheet deformation and deformation magnitude is established, and the effect of high-speed impact deformation to the forming ability of sheet metal is also analyzed, then the mechanism is treated as the basic theory of incremental impact deformation technology of sheet metal.the research results is also an analysis method for studying protection and damage of aircraft, vehicles, ships and other equipment sheet metal, at the same time, put forward a new way for rapid forming of sheet metal which is difficult to deform.Combined with the NC incremental forming technology characteristics, this paper described the basic principle and forming process detailedly and planed the the sheet metal forming path. Based on this research,this paper put forward a new kind of sheet metal forming path—variable pitch impact-helical processing path and made a preliminary study about this path.In order to validate reliability of the incremental impact forming,the test of the two typical surface panel, namely the ball panel and square taper panel was carried out with impact forming device. Some processing process parameters(impact velocity, impact1radius, feed rate, feed velocity, etc.) on the effect of sheet metal forming were studied. Forming defects of metal sheet were also analysised and the solutions were proposed.The test indicated the superiority of the incremental impact forming.The incremental impact forming has a wide range of adaptability, not only single concave surfaces but also convex and concave surfaces.Sheet formed by this forming approach is able to achieve high strain rate deformation, this forming approach is capable of enhance the forming ability of sheet metal, it also play a role in accurately forming of high toughness sheet metal.