The producers of rollformed profiles are increasingly interested in producing variable section profiles, in addition to a high level of flexibility.
The design of several vehicle chassis and body components require variable sections to meet structural or aesthetic requirements. The U or C-section profiles differ along the length, changing from the front end to the middle and again to the back end.
Today most of these products are manufactured through large presses or welding centers, which bend or weld together pieces of appropriate forms, in order to construct the beam of the desired section. In addition to the enormous manpower and space needed for production, the pieces obtained from the pressing and welding operation show tensions and deformations which consequently must be corrected by straightening operations.
STAM in 2013 has reached a new technological frontier. Stam has designed and built the first machine in the world capable of roll forming variable section profiles, for beams up to 7 mm thick.
The material used is HSLA steel with 350 to 500 MPa yield strength.
To meet this requirement the individual stands of the rollforming machine are independently movable. Each stand is equipped with its drive motor for the rolls and has a flexible positioning by means of other numerically controlled motorgears. In this way a wide range of workpieces can be manufactured using the same set of rolls.
The possibility of producing these special beams, up to 15 m in length, through the automatic and continuous roll forming method, therefore represents an enormous advantage in terms of flexibility and the personnel employed, and above all in terms of quality and cost of the final product .