Study on the wrinkling and edge irregularity during bending of a roll-formed plate

The bending tool design of a cold roll-formed blank has been discussed in this paper. The cold roll-formed blanks give a up and down bending line instead of a conventional straight line, The problems of wrinkling and edge irregularity occured frequently in such bending operation. A die design and blank pre-cutting methods are proposed in this paper to eliminate the edge irregularity. The radii of die and punch, punch profile, the gap of tools are considered as the design factors. The CAE method is adopted to obtain the measurements of the design of experiments (DOE). A fourth-order Bezier curve is proposed to desing the pre-cutting curve systemtically and automaticaly. The Golden section method is adopted to improve the pre-cutting curve design. The edge iregularity of a cold roll-formed balnk can be minimised by the proposed method. The wrinkling defects can be decreased but are not able to fuly elimiated.