Guideline to optimize the convergence behaviour of the geometrical springback compensation

Abstract

The need for car body structures of higher strength and at the same time lower weight results in serious challenges for the stamping process. To produce accurate parts at the end the stamping dies must be adjusted more or less by the amount of the springback in the opposite direction. Which stamping dies out of a multistage die set need to be adjusted, and how great the respective adjustment needs to be, is still quite often defined by practical experience and trial-and-error. Normally a certain number of compensation iterations based on the same compensation strategy must be realized and in addition to that, even the compensation strategy itself must be modified in some iterations in order to achieve accurate parts within tolerance. In contrast to the today still convenient trial-and-error optimization approach, a compensation guideline has been developed. Key content is the influence of the relevant compensation parameters, such as the measuring reference system (measurement system) including clamping of the parts (orientation of the springback part relative to the target part) and the amount of the compensation in the different stages (compensation factor and compensation strategy).