Parametric optimization of roll-hemming process in oblique planes with linear and non-linear trajectories

Abstract

The present work focuses on the optimization of geometric parameters for Roll Hemming process, considering linear and nonlinear trajectories on two oblique planes (3D). Here, the optimization parameters of interest are the roller radius, pre-hemming angle, fillet radius, and fillet height. The main aim of this work is to improve the quality parameters of the 3D process: roll-in, roll-out and wrinkle. Furthermore, a comparison is presented between numerical (Finite Element Method) and experimental data with optimal and non-optimal parameters for four different rollers (10, 15, 20 and 25 mm in radius). The experimental testing was performed using a 6 degree° of freedom (DoF) NACHI® SRA210 industrial manipulator, with a self-developed end effector. The parameters estimated through simulations were used to build the four rollers for experimental testing. Multiple roll hemming tests were performed on several U-shaped aluminum 6011 sheets (31,194 mm2), with a thickness of 0.9 mm. After a detailed analysis of numerical and experimental data, it was observed that the optimum parameters for the roller with 15 mm in radius generated the best quality in hemmed samples.