Influence of size effects on material properties and springback behavior of metal foils in micro bending: a review

With product miniaturization, the requirement on good forming quality and high dimensional accuracy of micro parts is increasing dramatically. In micro bending process, the springback, a critical factor for the accuracy of micro-bent parts, is significantly affected by size effects. In view of the strong influence of material properties on springback behavior, this paper first reviews the influences of three size-dependent factors on material properties, including foil thickness, grain size and thickness to grain size ratio. Afterwards, the review on the influences of these factors on springback behavior are presented, aiming at enhancing the understanding of relevant size effects and proposing a quantitative analysis approach to evaluate the dimensional accuracy of micro-bent parts.