Efficient Numerical Methods for Tool Optimization in Cold Forging

• Applicants: Professor Dr.-Ing. Fritz Klocke; Professor Dr. Sergej Rjasanow
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: from 2010 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 183821312

Lightweight design and resource efficiency in manufacturing technology require the use of high-strength materials and complex geometries in order to achieve equivalent part functionality, while reducing its weight. This poses a big challenge for forming tools and complicates their design with regard to tool durability and part precision. Therefore the use of numerical methods for tool design is essential. In this context the usual approach is to calculate the influence of isolated geometric elements on tool loads and part geometry and afterwards perform a manual tool optimization by means of an iterative process. While this procedure may improve single aspects, one cannot achieve a global tool optimization based on this strategy.In general a global optimum can be computed by means of mathematical algorithms. Nevertheless, their use for the optimization of forming tools features two weak points. Firstly, nowadays the computation of tool loads is almost exclusively performed by means of the Finite Element Method (FEM). This method requires high computational effort for a holistic computation of tool/ workpiece-interactions. Due to the large number of iteration steps this renders the optimization process inefficient. Secondly, due to limited computing time one often omits the influence of machine stiffness on tool loads. Therefore, the input information for the optimization process already contains significant inaccuracies.In order to remove these shortcomings, in the context of the applied project new efficient simulation tools and a holistic, systematic approach for tool optimization, based on the actual tool loads during process, will be developed. Thereby the goal of this project, namely a significant increase in durability of cold forging tools and in the precision of the parts by means of intelligent, numerical, iterative tool design, will be achieved. The substantial novelty is the development of efficient coupled methods for the computation of tool loads by means of elastic modeling, while accounting for process/machine-interactions, as well as the numerical compensation of component deviations caused by elastic tool strains. By integration of the newly developed computing methods into a methodology for automated tool optimization, a time-efficient computation of the optimized tool geometry can be realized despite the large number of iteration steps. In order to reach this goal and to develop constructive interdisciplinary approaches scientists from manufacturing engineering, numerics and applied mathematics will closely work together for the whole research period.

• DFG Programme: Research Grants