Multi-point forming technology for sheet metal

摘要

Multi-point forming (MPF) is an advanced manufacturing technology for three-dimensional sheet metal parts. In this paper,rnThe MPF integrated system is described that can form a variety of part shapes without the need for solid dies, and given onlyrngeometry and material information about the desired part. The central component of this system is a pair of matrices of punches,rnand the desired discrete die surface is constructed by changing the positions of punches though the CAD and control system. Thernbasic MPF process is introduced and the typical application examples show the applicability of the MPF technology. Wrinkle andrndimple are the major forming defects in MPF process, numerical simulation is a feasible way to predict forming defects in MPF.rnIn conventional stamping, the mode to form sheet metal with blankholder is an effective way to suppress wrinkling; the same isrntrue in MPF. A MPF press with flexible blankholder was developed, and the forming results indicated the forming stability of thisrntechnique. Based on the flexibility of MPF, varying deformation path MPF and sectional MPF were explored that cannot bernrealized in conventional stamping. By controlling each punch in real-time, a sheet part can be manufactured along a specificrnforming path. When the path of deformation in MPF is designed properly, forming defects will be avoided completely and lagerrndeformation is achieved. A work piece can be formed section by section though the sectional MPF, and this technique makes itrnpossible to manufacture large size parts in a small MPF press. Some critical experiments were performed that confirmed thernvalidity of two special MPF techniques.