LAUSR

Abstract Some local features usually have to be formed on the sheet metal parts for further usage, e.g. assembly. Stamping has been extensively applied to form the local features, but in an inconvenient and inefficient way. In this paper, a novel forming technique named clamp forming is proposed as an alternative to stamping to form the local features on base sheet metal parts. Taking the step feature on a hat-shaped rail as an example, the clamp forming technique is illustrated and implemented. Based on a force magnification apparatus, the clamp forming can enlarge the traction force by tens of times into a large forming force. The finite element model of the clamp forming is established and forming quality is numerically evaluated through simulation. The influences of the key process parameters, including die radius, over-bending angle, die arc radius and driving force are numerically investigated, and the optimal process parameters are finally determined. The forming apparatus is developed and forming experiments are carried, and excellent forming quality can be achieved by employing the optimal design. The clamping forming technique provides a more load-saving and economical method than stamping to form local features on sheet metal parts.