1998 Volume 48 Issue 4 Pages 163-167
A new CNC incremental process with ORIGAMI method in which a shell is formed from a flat blank by means of pre-bending process (ORIGAMI process) and subsequent incremental stretch-expanding process has been proposed in order to prevent the thinning phenomena. Although the process has the advantage of preventing the thinning phenomena, a method for preventing the forming defects, such as wrinkling, remains unknown. In this study, the forming defects occurred in the process have been experimentally investigated. Aluminum and its alloy blanks were bent into a shape inscribed in an automobile trunk-lid-type panel, and then stretch-expanded to the panel shape, and the deformation behavior was examined. It was found that formability of the process is dependent not only on the degree of surface distortions of the panel, such as wrinkling and puckering, but also on the remainder of pre-bent shape caused by elastic deflections during the stretch-expanding process. Experimental results showed that these distortions and the remainder of pre-bent shape can be overcome by employing the stretch-expanding process with reciprocating tool-path.
