Intelligent Manufacturing Systems: Controlling Elastic Springback in Bending

A rotary compression bending system with automated closed-loop feedback control has been developed. The overall goal is to improve the dimensional accuracy of formed shapes by transferring in-process data into a steering model for instant springback compensation. An analytical method based on the deformation theory of plasticity was employed to develop a physically-based steering model. Unlike alternative control strategies, the present control strategy is attractive for volume production since the approach does not impact cycle time. More than 150 tests of AA6060 extrusions were conducted to determine the capability of the technology. Prior to forming, the material was exposed to different heat treatments to provoke different stress-strain characteristics. The results show that the springback-angle standard deviations were improved from ±0.41° to ±0.13° by activating the closed-loop feedback system. Since the dimensional process capability is improved by a factor of three, it is concluded that the technology has high industrial potential.