Investigation On Deformation Law Of Incremental Forming Combined With Stretch Forming

The NC incremental forming technology is an advanced dieless flexible manufacturing technology,which is based on the part geometry generates NC code to drive the tool head to process the sheet metal layer by layer,so that the sheet local cumulative plastic deformation and machining parts.It has the characteristics of high flexibility,shortened product development cycle and significant cost reduction.In traditional incremental forming process,the thickness of the parts obey the cosine law,the larger angle or the straight wall parts cannot be formed,and the springback of forming parts is larger when forming small curvature parts,which limits the development of incremental forming technology.The stretch forming process has many advantages,such as less springback,thinning thickness,and forming sharp edges.Combined with the stretch forming,the deficiency of single incremental forming can be greatly reduced.The main contents of this paper are as follows:(1)In order to understand material performance parameters,the mechanical properties of 5754 aluminum alloys were tested,and the mechanical properties of three kinds of thickness were studied,and conduct a punch bulging test and forming limit test for incremental forming for one thickness,thus,The bulging forming limit diagram and incremental forming limit angle and forming limit strain point of the thickness material were obtained.The difference between the two forming limit strains was compared.(2)Take a space curvature depression parts as the object,to research and analysis the incremental forming combined with stretching forming stress and strain,thickness distribution,tool head and support die force and cross-section accuracy by using the finite element simulation technology,and different process parameters are intruduced to test their influence on the thickness distribution of parts and tools the head and the supporting force and section model accuracy,thus,obtained the optimization of process parameters.(3)Make a comparative analysis through the experiment on single incremental forming and incremental forming combined with stretching forming on the forming precision,appearance quality,efficiency,The influence laws of lubrication conditions and processing methods on the precision of parts by incremental forming combined with stretching forming is studied through experiments.(4)After pre-stretching,vertical part was formed by using different incremental forming technology.The influence laws of stretching angle on bending incremental forming combined with stretching forming is studied..The thickness analysis of the formed parts shows that the thickness of the straight wall area is less in the stretching-bending incremental forming combined with stretching forming,which is more suitable for machining the high height straight wall parts.