Abstract:Incremental forming process is recently developed to form tubular parts. The fabrication cost and accuracy could be optimized if the effects of process parameters and the optimum values are specified. The aim of this research is using incremental forming of copper tubes to convert a circular tube into a square cross-sectional part. An experimental setup, consisting of a spherical forming punch and a fixture for clamping the tube is designed. The forming punch movement is controlled by a CNC machine. Full factorial design of experiments is carried out in order to determine the effects of process parameters including linear velocity, radial feed, and axial feed of the tool on the thinning ratio and the maximum outer diameter of the square cross-sectional parts. Results show that the radial feed has the major influence on the thinning ratio, while the axial feed plays the major role for the final profile. Increase of radial feed results in higher thinning ratio, and decrease of axial feed results in better shape conformity. Linear velocity does not have a significant effect on thinning ratio. Regression models are also given for predicting the determined responses.

Key words: tube incremental forming; square cross-section; radial feed; axial feed; thinning