Numerical and experimental investigation on the deformation mechanism of micro single point incremental forming process

© 2018 The Society of Manufacturing Engineers Single-point Incremental Sheet Forming (ISF) is a die-less forming process with advantages of high-flexibility, low-cost and short lead time. Recently, micro components have been employed in many applications, especially in medical industry using as implant components, surgical tool and tooth caring accessories etc. Therefore, the reduction of component size to micro-domain has becoming one of the key elements for the development of ISF technique, which will encounter many challenges, such as reduction of formability, tool wear, inaccuracies in tooling fabrication, etc. This work combined numerical and experimental approaches to study the deformation mechanisms in micro ISF process. Aluminum 1145 soft-temper foils with thickness of 38.1 μm and 50.8 μm were employed. A truncated pyramid with variable half-apex angle was employed here as the standard geometry for measuring the maximum forming angle that could be achieved in micro-ISF process. The result shows that forming angle has direct link with material formability. A full tool path micro-ISF finite element model has been developed using incompatible mode eight-node brick element C3D8I, which is capable to capture the shape and thickness distribution of the formed parts with most accuracy and least computational time. The thickness distribution of the workpiece was compared with the Sine Law to unveil the additional stretch region appearing at the top edge of the formed feature in the micro ISF as compared to macro ISF.