Influence of size effect on the springback of sheet metal foils in micro-bending

► A model is proposed for analysis of the unloading springback of sheet metal foils in micro-bending process based on the surface layer model. ► FEM simulation based on the proposed model is conducted. ► The grain size and geometry effects in micro-bending are studied. ► How the size effects affect the springback of sheet metal in micro-bending is revealed.