Inverse Identification of Process Variations for Thin Steel Sheet Bending

Abstract

The stability of a metal forming production process is influenced by several sources of scatter such as variation of material and lubrication properties. Identification of the sources of variation is needed to optimize the process settings or to design a control strategy for the process. Many engineers point out sources of variation by experience, but in complex cases a computational identification algorithm may be used to investigate the process. When using parameter estimation in a control system, process forces can be used for the estimation. However, many parameters may influence the process forces. Therefore extensive models are needed to be able to identify the process parameters, including parameters such as tooling misalignment. In the current work, a thin steel flap bending process is studied. Measurements from an industrial press are used to identify the process parameters. A metamodel based inverse analysis procedure is used. The procedure is extended with proper orthogonal decomposition (POD) of the force curves to increase its convergence rate.

Model-based control of strip bending in mass production

“…For the third flap, a higher force is observed, which is caused by misalignment of the tool: the punch makes contact with the lower tooling. This has been verified with simulations of the process [9]. At around À0.025 s the tip of the flap makes contact with the lower tooling.…”

The effect of tooling deformation on process control in multistage metal forming

“…2a). However, misalignment of the punch may lead to contact between the punch and the die during free bending, leading to a higher force [8]. The effect of misalignment is observed for the third bender when the forging force is at 15kN (Fig.…”