Optimal Process Design of an Optimal, Single-Stage, Symmetrical L-Bending Process Employing Taguchi Method with Finite Element Method, and Experimental Verification Thereof

Abstract

A single-stage, precision, symmetrical L-bending process is developed, which employs a forming-load control die for progressive sheet-metal forming of a circuit-breaker. It is targeted to replace the traditional two-stage symmetrical L-bending process, which features rough bending followed by fine sizing/adjustment to meet the required geometrical tolerances. The new process requires optimization since the die controls springback caused by the pressing load imparted to the shoulder by the same die. The Taguchi method is thus used to optimize the process design using an elastoplastic finite element method in terms of the tilt angle after springback and the leg length of the resulting bent region. The finite element predictions of the optimized process are in excellent agreement with the experimental data and there are no cases of failure.