Analysis of a new process for continuous hot extrusion utilizing the theory of similarity

• Applicant: Professor Dr.-Ing. A. Erman Tekkaya
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 437724884

Aim of the research project is the fundamental analysis of a new process for continuous hot extrusion. The new process combines the conventional methods of direct and indirect bar extrusion using a moving valve, and enables the constant extrusion of aluminum profiles. In a preliminary work, a possibility was found to replace the movable valve by a stationary, immovable valve. With both variants, the usual non-productive times can be used for profile extrusion. In case of the conventional direct and indirect extrusion processes, the dead cycle times lead to unsteady conditions, which in particular influence the profile temperature. With the new continuous process, a stationary extrusion process can be achieved, which makes it easier to regulate the profile temperature. To date, no press for continuous hot extrusion is available and numerical methods cannot be validated for the new process. Therefore, the continuous extrusion will be analyzed on the basis of scaled experimental models using the model material plasticine, numerical simulations and selected experiments with aluminum on a conventional direct extrusion press. In particular, material flow and relevant process parameters are determined and investigated. Furthermore, it will be investigated to what extent a movable valve can be replaced by a stationary valve. For both types, with and without moving valve, a process window is set up. In particular, for the second solution it must also be determined under which conditions the material flows only in the pressing direction and continuous pressing is possible. To confirm the similarity between model and aluminum extrusion, suitable replacement experiments will be performed on an existing extrusion press.

• DFG Programme: Research Grants
• Co-Investigators: Dr.-Ing. Christoph Dahnke; Dr.-Ing. Soeren Gies