Modelling of dynamic loads during series operation for optimisation of part holder design

Abstract

Energy and resource efficiency today are fundamental challenges in production technology, which also arise in the production of sheet metal body parts when using state-of-the-art press technology. Since sheet metal forming processes are becoming more and more complex due to modern design of car body shape, the tools for producing body parts are increasing in size and modern press technology is developing correspondingly faster. Simultaneously, produced tools for new car models must withstand applied process related loads emerging during lead time of model to ensure a robust production process. Based on the increase in productivity supported by servo press technology of today and resulting higher demands on required tool strength, part holders assembled in large line dies in particular belong to critical tool components. In this paper, an optimization concept for part holder design is presented. Higher acceleration of press ram and upper tool results into higher levels of dynamic impacts, which can lead to critical load cases originating from spatial mass distribution of part holder. Occurring loads are reduced by use of damping elements. The distribution of damping elements into part holder structures is optimised according to the mass distribution of the part holder and the design of the upper die. For this purpose, dynamic effects of the tool were modelled based on analytical models and verified by multi-body simulations and corresponding stress calculations. The application of dynamic load characteristics of tool components thereby allow realistic modelling of distributed mass and force effects. Finally, simulation results were validated on the basis of tests under series production conditions.