Forming of complex functional elements on sheet metal (A02)

Third Party Funds Group - Sub project

Start date : 01.01.2009

Formfüllung der Kavität eines Fließpressprozesses bei Verwendung geometrisch unterschiedlicher Formelemente / Insufficient mold filling in a cold forging process by use of different functional elements

Overall project details

Overall project

TRR 73: Manufacturing of complex functional components with variants by using a new sheet metal forming process - Sheet-Bulk Metal Forming Jan. 1, 2009 - Feb. 28, 2024

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Project details

Short description

Objective of subproject A2 is a fundamental analysis for the manufacturing of complex functional parts out of sheet metal using cold forging operations. A special focus is set on short process chains. Within the current second project phase it is investigated, whether it is possible to transfer the existing knowledge on the forming of geometrically identical functional elements on element combinations of different shape and size. However, as the figure below illustrates, a different mold filling can be observed, which is directly related to the choice and placement of the cavities. Hence strategies have been developed and verified in further investigations to encounter this challenge. Using numerical and experimental investigations, the effectiveness of “Tailored Surfaces” and Tailored Blanks has been verified for the targeted control of the material flow.

As a result of the typically high contact areas between the workpiece and the tool, the tool loads approach the current limits of conventional tool steels and reinforcement systems. Hence, tool stresses have been analyzed in order to identify the central influencing variables. The investigation shows that the resulting tool stresses are dependent on the geometrical form and their placement. Based on the results, the forming tools have been designed accordingly. Furthermore, in order to improve tool life and reliability, the process forces have to be made controllable by means of a further development of the tool technology. This is achieved by the use of alternative non-circular reinforcements, which enable the targeted adjustment of its properties in order to encounter the asymmetrical tool loads resulting from the forming of non-similar functional elements. Besides this, research is conducted on fatigue strength characterization of high strength tool steels in order to give precise predictions regarding the tolerable tool loads and therefore enable the full use of the potential of the tool steel in question.

This project is supported by the German Research Foundation (DFG) within the scope of the Transregional Collaborative Research Centre on Sheet-Bulk metal forming (SFB/TR 73).

Scientific Abstract

Zur simultanen Herstellung geometrisch unähnlicher Formelemente an Blechen durch Fließpressen ist aufgrund des bisher unverstandenen Formfüllungsvorgangs sowie der komplexen Werkzeugbeanspruchung die Erforschung der Grundlagen zur Prozess- und Werkzeugauslegung erforderlich. Dazu werden simulationsbasiert und versuchsgestützt die grundlegenden Mechanismen untersucht, welche bei der einstufigen Ausformung zweier benachbarter Formelemente vorherrschen. Darauf aufbauend werden die Verfahrensgrenzen, auch unter Berücksichtigung vorausgehender und nachfolgender Umformprozesse, identifiziert sowie Konzepte zu deren Erweiterung entwickelt.


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