Metal-flow phenomena in computerized numerically controlled incremental stretch-expanding of aluminum sheets

Abstract

An incremental forming process in which a blank is formed to fit on a tool-envelope surface made by relative motion of a tool around the blank, has been developed. The incremental forming process seems to be suited to small-lot production from viewpoint of a die-less forming operation, and are also thought to be important in metal-flow control operation. So, the possibility of metal-flow control in CNC incremental stretch-expanding of aluminum sheets was examined. Effect of tool path schedule on strain distribution and forming limit in shell components is examined using hard aluminum sheet. It is found that the tool path schedule has influence on strain distribution in shell components, and the associated metal-flow has influence on the forming limit. Thus, it was concluded that the incremental stretch-expanding seems to be a promising working process for flexible manufacture from viewpoint of metal-flow control.