板材柔性拉伸成形研究进展与展望

Review and outlook on sheet metal flexible stretch forming

传统横向拉伸成形和纵向拉伸成形过程中,均存在夹持机构运动与过渡区板材变形不协调现象,进而诱发板材与模具不贴合、变形不均匀、起皱甚至拉裂问题。为降低零件制造成本、提高板材贴模度和零件成形精度,开展板材柔性拉伸成形研究极具学术研究价值和工程应用前景。综述了板材柔性拉伸成形模具柔性化和加载机构柔性化的研究进展,重点阐述了多辊下压式和多夹钳式柔性拉伸成形原理、装备构成及成形特点,分析了过渡区长度、板材加载路径等主要工艺参数对零件成形质量的影响,简述了力/位移加载分布式柔性拉伸成形方法,最后展望了板材柔性拉伸成形的发展方向。

In both traditional transverse and longitudinal stretch forming processes,the movement of clamping mechanism is inconsistent with the deformation of sheet metal in transition zone which leads to forming defects,such as unconformability of sheet metal to forming die,uneven deformation,wrinkling or even fracture.In order to reduce the manufacturing cost,improve the conformability of sheet metal to forming die and obtain high precision of formed parts,the research on sheet metal flexible stretch forming is of great academic value and wide application prospect.The review on forming die flexibility and loading mechanism flexibility in sheet metal flexible stretch forming was introduced.The forming principle,device buildup and forming characteristics of multi-roller and multi-gripper flexible stretch forming processes were elaborated emphatically.The effects of the main process parameters such as the transition length and loading path of sheet on forming quality were analyzed concretely,and the distributed force/displacement loading stretch forming processes were described brief-ly.Finally,develop directions of sheet metal flexible stretch forming were pointed out.