Development of an Incremental Tool Concept on the Basis of Rotating Tools for Sheet Metal Forming

• Applicant: Professor Dr.-Ing. Gerhard Hirt
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: from 2009 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 159280604

Rotary Peen Forming (RPF) is a new and innovative process for the forming of extensive sheet metal structures. The forming characteristics are comparable to shot peen forming (SPF). This incremental forming process uses impactors that are rotating around a hub. During rotation the impactors are stabilized and held on the circular path by the centripetal force. An impact on the workpiece surface induces localized plastic deformation which leads to a macroscopic curvature of the workpiece. The induced specific energy varies depending on the rotation speed, angle of impact and length of the impactors. In the same way as in shot peen forming the solidity ratio can be varied by adjusting the feed rate and the rotation speed.The aim of developing the RPF process is to avoid the process related disadvantages of shot peen forming, i.e.- high investment costs- low energy efficiency- partly difficult process control with overlapping paths- high amount of peening materialThis leads in turn to a highly productive and flexible alternative to shot peen forming.The main goals of the first funding period were the acquirement of a fundamental understanding of the process and the development of new tool concepts. It turned out that the originally planned construction on the turret of the IBF shot peen forming machine is not suitable as a tool holder, as it excessively reacts on vibrations. Therefore, an experimental setup has been realized, which allows an exact comparison of different tool concepts. Nevertheless, due to limited traveling distances this setup is not suitable for the production of application-oriented components.In the second funding period described in the present proposal an application-oriented setup will be constructed. The setup should allow for a reduction of process time and the production of complex workpiece geometries. Therefore the modification of an already existing industrial robot is planned, so that different tool concepts can be mounted on the robot arm. Thus, a very flexible forming of workpieces is possible because of the availability of up to six spatial degrees of freedom. Furthermore, the already developed tool concepts from the first funding period will be optimized for this setup and a safe and repeatable process control has to be developed. Subsequently, application-oriented workpieces will be produced which demonstrate the capabilities of Rotary Peen Forming.

• DFG Programme: Research Grants