2013 Volume 54 Issue 630 Pages 618-622
Products formed using a conventional cold-roll forming machine have cross-sectional profiles constrained to a single width along the longitudinal axis. Products with cross-sectional profiles varying in width in the longitudinal direction, namely, flexible cross sections, cannot be formed using a conventional cold-roll forming machine. In recent years, research and development of a flexible cold-roll forming machine (FCRFM) controlled by a PLC (Progressive Logic Controller) Unit to form products with flexible cross sections has been carried out in Japan and Europe. In this study, the relations between the motions of the roll stand of the FCRFM and the fluctuations in flange width along the longitudinal direction caused in forming the blank steel sheet are investigated to clarify the mechanism of the occurrence of the faults of flange dimension. It is found that when the forming point of the roll is on the same line as the center line of the rotational spinning shaft of the turntable, the flange width of the product formed becomes narrower at the corner and oblique parts of the blank sheet. The optimum method of forming a constant flange width is to keep both the bending point of the roll and the rotational spinning shaft of the turntable in the same concentric circle, in which the center of the concentric circle is that of the circle making the corner part of the blank sheet.