An assessment of various process strategies for improving precision in single point incremental forming

Single point incremental forming (SPIF) is a process with the capability to form complex geometries using a tool of very simple geometry, without the need for a matching die. However, large elastic springback resulting from the die-less nature of the process can cause problems if high levels of accuracy are required. The aim of this investigation is to use numerical modelling to investigate different strategies to improve the process precision. A finite-element (FE) model has been used to investigate the effects of adding a backing plate, a supporting kinematic tool and modifying the final stage of the tool path. The results show that the backing plate will minimise the sheet bending near to the initial tool contact location; the additional kinematic tool will reduce springback; and the extension of the tool path across the base of the sheet will eliminate the pillow effect. The cumulative effect of introducing these features to the process shows an improvement in the overall accuracy of the profile and in the thickness distributions of the final product. The results contribute to a better understanding of springback in SPIF.