Local heating in robot-based incremental sheet metal forming

• Applicant: Professor Dr.-Ing. Bernd Kuhlenkötter, since 9/2016
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: from 2011 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 186246236

The term Roboforming describes a robot-based incremental sheet metal forming process in which two cooperating industrial robots form a sheet metal by repeated localized forming with two simple and workpiece-independent tools. This kinematically controlled forming process can be used for a fast and cost efficient production of sheet metal prototypes or parts in small lot sizes.The aim of the first funding period was to increase geometrical accuracy and to reduce springback and subsequent deformation of already formed areas for simple part geometries. Therefore the forming machine had to be upgraded with a system for localized resistance heating of the moving incremental forming zone. It was proven that with this incremental heating method a reduction of the forming forces according to flow curves at elevated temperatures known from other forming and heating processes can be achieved qualitatively in steel forming. Also a reduction of subsequent deformation was achieved. Within this first funding period the upgrade of the forming machine was designed and implemented. According to this the phenomenological basics, the design and engineering of forming tools with inner cooling and further cooling systems, an implementation of highly dynamic temperature measurement and control and the start of operation of the facility was achieved. Additionally stable process conditions for the heating process were identified. Also the process-specific factors of influence, their interdependencies and their relationship to the target factors of the process should be investigated and optimized.The aim of this new project is to overcome existing constraints of incremental sheet metal forming by forming at elevated temperatures. Therefore both temperature measurement and control will be optimized for more complex parts. According to the achievable geometrical accuracy when forming at elevated temperatures, geometrical deviations resulting of the heating shall be compensated.Within this second funding period, especially materials which are hard to form at room temperature shall be focussed. Within this material range forming of titanium and Complexphase-steel will be realized and the influence of this forming process on the material properties will be analysed. In incremental sheet metal forming the maximum formable sheet thickness very often is limited. For steel forming an investigation of the influence of this process variant on sheet thickness restrictions will be carried out. With this research programme, further fields of application for incremental sheet metal forming will be made accessible.

• DFG Programme: Research Grants
• Ehemaliger Antragsteller: Professor Dr.-Ing. Horst Meier, until 9/2016