Method for producing roll formings

摘要

A method for producing a roll forming allows the hemming step and the roll-forming step to be contiguously performed in a single production line. The first ripping step (E) tears off a side edge strip along the first groove formed by the first grooving step (B) to form a first edge portion having a gradually changed sectional shape. At least the first grooving step (B) and the first ripping step (E) are performed contiguously with the roll-forming step (A) by utilizing the sheet or product conveyance force provided in the roll-forming step (A).