Conventional roll forming process is one of the most common sheet metal forming processes where the strip is
deformed by rotating rolls mounted on successive stands to produce a large variety of profiles continuously at high
production rates. This process can only produce profiles with constant cross sections. However, a lot of
components used in the automobile, railway cars, ship construction, and building industries have variable cross
sections. Therefore, flexible roll forming has been developed recently to produce variable cross section profiles.
Ortic (2001) developed a flexible roll forming machine for the production of 3D roof panels. Groche et al. (2003b)
described a new tooling concept for flexible roll forming process. Ona (2005) proposed the intelligent roll forming
machine for forming variable cross sections.
Contrary to conventional roll forming process, in flexible roll forming process the forming rolls are not fixed in
their position but are moved along a path which describes the desired bend line of the profile. The forming rolls’
positions must be such that they always are tangent to the deformed flange to avoid its additional deformation
(Groche et al., 2008a). According to Fig. 1a, this is realized by superposition of a translational and rotational
movement of the rolls. Typically these motions are controlled by computerized numerical controls. A flexible roll
forming machine is able to produce profile families only by changing its control program