Theoretical analysis of rolling-extrusion process of axi-symmetrical parts

Rolling-extrusion process is potentially one of the new manufacturing technologies of stepped, hollowed parts. In this process material is formed by means of three rotational tools. The charge is provided by means of a pusher pushing the billet in a working space between the profiled rolls. Numerical research of this process in a few tools variants with the use of hollowed billets were made in order to determine the influence of tool shape geometry in this new forming method. In numerical simulations the MSC SuperForm2005 software was used. This software based on the finite element method and it allowed for analyzing of the influence of different geometrical and technological parameters on the course of the rolling-extrusion process. On the basis of calculations it was stated that the process stability depends on different shapes of profiled rolls and its rotary velocities correlated with pusher displacement. One of the phenomenon which disturbed the proper course of the hollowed parts manufacturing process was excessive ovalization of cross-sections of the formed workpiece. This disturbance was eliminated by the application of correctly combined tools velocities and reduction ratios. In this work the authors focused on determining the practical range of tools geometrical and kinematical parameters guaranteeing the proper course of the rolling-extrusion process of hollowed parts.