Abstract: Fixed cross rolling is an improved process to achieve the near-net forming of the screw rotor with big-spiral teeth， and the key of the process is to couple with the profile curves. In the rolling process， the meshing relationship between the roller and the workpiece is different from the original between the screw rotors， therefore， couple profile of the roller and the workpiece need to be redesigned to accommodate to variable rolling forming. Taking a driven rotor as an example， the geometric model of the coupled profile curves of the roller and the driven rotor propitious to fixed cross rolling was rebuilt by means of envelope analysis. Then，using matrix theory， the corresponding parametric equations of the coupled profile curves were established to realize the parametric design of the roller profile and increase technology universality. Finally， the dynamic simulation results verified the correctness of the previous parametric equations and without the interference phenomenon.

Key words: coupled profile curves, fixed cross rolling, driven rotor, cross wedge rolling, dynamic simulation