Abstract
Effect of tool rotation direction on forming limit in friction stir incremental forming was studied. Commercial A5052 aluminum alloy sheets with a thickness of 0.5 mm were formed into frustum of pyramid shape. Forming limit was investigated by changing relative direction of tool rotation. From the experimental results, forming limits by both rotation directions of advancing and retreating were same, however, the range of formable working conditions by advancing direction was smaller than that by retreating direction. Evaluating the forming limits in relative velocity between the tool surface and the sheet, no difference of forming limit was obtained between forming by advancing direction and retreating directions. Moreover, by using relative velocity between the tool surface and the sheet, formable working conditions can be estimated by the combination of not only the tool rotation direction but also the tool rotation rate and the tool feed rate.
