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B3 - Surface Structures



Generation of Predetermined Surface Structures by Simulation based Process and Tool Design when Milling Free-Formed Surfaces

Project Status: Active

Last Update: 20.02.2019



Members


In subproject B3, the simulation and milling of deterministic surface structures on large tool areas for sheet metal forming is investigated. These should be used to increase the previously insufficient form filling of functional elements and cavities by regulating the material flow in the tool. An efficient method for applying deterministic surface structures is the high feed milling. In high-feed milling, the process parameters as well as the cutting edge shape of the tools have a significant influence on the surface structure and its properties. By simulating the milling process, it is possible to determine the properties of the surface structures before the real milling process. So far, this approach has been able to simulate and generate a large number of tribological surface structures and to validate them in sheet metal forming tools for material flow control. However, it has been shown that the conventional milling tools which have been used up to now have only partially been able to introduce the required surface characteristics due to their limited geometry. In the third phase, a simulation-based development of milling tools for the structuring of surfaces is provided. By designing different cutting geometries, based on the findings of the second phase, surfaces will be produced which fulfill the required surface characteristics for the sheet metal forming process. In the following, these are analyzed by means of experimental investigations for their friction behavior.

 b3 phase3 b1 en
Process scheme high-feed milling and experimental surface structure on forming tool
 
In the structuring of tool surfaces, geometrical deviations and surface artifacts can arise in transition regions like radii, as well as in cavities, which are largely due to the limited machine dynamics. These can not yet simulated with the developed milling simulation since this does not consider the acceleration behavior of the milling machine. The previously used milling simulation is to be further developed in order to be able to simulate the dynamic properties, such as, for example, the acceleration and deceleration behavior of the machine. In forming tests as well as tribological tests, it was found that the surface structures machined produced pressure stresses in the surface, but were still subject to various wear mechanisms. Therefore, another goal of the third phase, in cooperation with TP C1, is to examine the developed surface structures for their wear behavior. The relationship between the surface characteristics (Rz, Rpk), the inherent stresses σ prevailing in the edge zone as well as the processing parameters (vc, vf) of the surface structures with the wear state of the surfaces are investigated.
 
During sheet metal forming, the tool surfaces are subjected to high mechanical stresses (2000 MPa) in certain areas. This can lead to a deformation of the respective tool surfaces. In order to counteract this error, the extent to which a gradation of the surface structures can optimize these areas is to be investigated. In particular, regions subjected to higher loads as well as transitions to radii and cavities are to be graduated in such a way that plateau-like regions are formed. For example, the surface structures should have lower profile heights in areas which are subject to higher loads, so as to be able to accommodate an increased load collective.
b3 phase3 b2 en

Statistical process model and experimental modified surface structures

 
 


Working Groups


Publications

    2019

    • Löffler, M.; Schulte, R.; Freiburg, D.; Biermann, D.; Stangier, D.; Tillmann, W.; Merklein, M.: Control of the material flow in sheet-bulk metal forming using modifications of the tool surface. In: International Journal of Material Forming, 12(2019), Springer, pp. 17-26
    • Freiburg, D.: Hochvorschubfräsen zur Strukturierung von Werkzeugoberflächen für die Blechmassivumformung. In: Dirk Biermann (Edt.): Schriftenreihe des ISF, (2019)97, Essen: Vulkan Verlag GmbH, pp. 192
    • Tillmann, W.; Hagen, L.; Stangier, D.; Michael, P.; Tolan, M.; Sakrowski, R.; Biermann, D.; Freiburg, D.: Microstructural characteristics of high-feed milled HVOF sprayed WC-Co coatings. In: Surface and Coatings Technology, 374(2019), pp. 448-459

    2018

    • Freiburg, D.; Finkeldey, F.; Hensel, M.; Wiederkehr, P.; Biermann, D.: Simulation of surface structuring considering the acceleration behaviour by means of spindle control . In: Int. J. Mechatronics and Manufacturing Systems, 11(2018)1, published
    • Freiburg, D.; Biermann, D.: Simulation-based tool development for structuring of surfaces for sheet bulk metal forming tools. In: Procedia Manufacturing, 15(2018), doi.org/10.1016/j.promfg.2018.07.245, pp. 467-474
    • Freiburg, D.; Aßmuth, R.; Garica, R.; Biermann, D.; Henneberg, J.; Merklein, M.: Adaption of tool surface for sheet-bulk metal forming by means of pressurized air wet abrasive jet machining. In: Production Engineering, (2018), Berlin Heidelberg: Springer, pp. 1 -7

    2017

    • Freiburg, D.; Löffler, M.; Merklein, M.; Biermann, D.: Surface Structuring of Forming Tool Surfaces by High-Feed Milling. In: Robert Schmitt; Günther Schuh (Edt.): 7. WGP-Jahreskongress, 7(2017)7, Aachen: Apprimus Verlag, Aachen, 2017 , pp. 63-70

    Presentations

      2018

      • 26.04.2018: Stangier, D.: Bionisch inspirierte Oberflächenstrukturen und nanostrukturierte PVD-Hartstoffschichten für die Blechmassivumformung, Sigmaringen BisOn Netzwerktagung
      • 17.09.2018: Freiburg, D.; Biermann, D.: Simulation-based tool development for structuring of surfaces for sheet bulk metal forming tools, Toyohashi, Japan

      2017

      • 05.06.2017: Freiburg, D.: Surface Structuring of Forming Tool Surfaces by High-Feed Milling , Aachen