A Model of the Sequential Bending Process for Manufacturing Simulation

Abstract

The process of sequential bending has many applications, but the most common is for developing cylindrical shapes from plate. The objective of this work is to develop a process model for use in simulation of the manufacturing of such objects, to provide design sensitivity information, and to explore the potential for improved process control. The process is modeled here as a series of overlapping two-dimensional three-point bends, where the overlap includes the plastic zone from previous bends. This deformed zone is modeled both as a non-flat initial geometry for the next bend and as a locally strain-hardened material with residual stresses. For process simulation the model is incorporated into a measurement and control simulation that allows either operator-controlled algorithms or automatic control to be employed. A series of experiments were performed on plates of steel, aluminum, and brass to examine the accuracy of the model. Good agreement was found, but only after adjusting the assumed material parameters. Results show that the prior bending history has a marked effect on the basic process resolution, and therefore on the effective precision and sensitivity of the process.