On Strain Distributions in the Formation of Flexible Channel Section Development of Flexible Cold Roll Forming Machine

Abstract

For about 70 years, cold roll forming machine has been used to make products whose cross section are uniform in the longitudinal direction. Products formed by this machine are used as construction materials, aircraft structural parts, automotive body parts, oil pipelines and so on. Research and development on production technology to make products with higher quality and higher dimensional accuracy has been carried out. Furthermore, analytical research using FEM method has been vigorously done. On the other hand, in accordance with the development of computer control system combined with CPU technology in recent years, research on development of the flexible cold roll forming machine that can form products with varying width in the longitudinal direction has been carried out in Japan and Europe (1)〜(4). The new cold roll forming machine combines the normal cold roll forming technology with computer-control technology, making it possible to form the long sized products whose cross sections vary in width. In 2011, we presented a paper that described the design method of flexible cold roll forming machine and the shape defects caused by this machine. In this paper, the behaviors of surface strains occurred in forming flexible section, which are measured by using resistance wire type strain gauges, are described from the view point of making clear the cause of occurrence of shape defect.