Analysis of Anisotropic Effects in Single Point Incremental Forming

Incremental Sheet Forming (ISF) has great potential to form complex sheet metal parts without using component specific tooling. Formability in ISF process is higher than the conventional forming processes but achieving good geometrical accuracy is a challenging task. Anisotropy of material causes variation of thickness with respect to rolling direction, which effects stiffness, spring-back and accuracy. Variation of thickness and spring-back with rolling direction is studied using experimental and numerical analysis for a conical geometry formed using extra deep drawing steel having high anisotropy. Comparison of anisotropy and isotropy is done using numerical analysis. Results showed that, thickness is low in the direction with low ratio of width to thickness strain (r-value), resulting in higher spring-back. This directional property has to be considered in tool path design to enhance the accuracy. When material is assumed to be isotropic, variation of thickness and spring-back with respect to direction is insignificant.