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B2 - Micro Elements



Machining of Molds with Filigree Structures for Sheet-Bulk Metal Forming

Project Status: Active

Last Update: 10.07.2019



Members


Within the context of the fundamental investigations of the previous project phases for the micromilling of high-strength tool steels, process strategies could be developed with which filigree shape elements with dimensions of a few millimetres (< 3 mm) can be produced almost burr-free and with an arithmetic mean roughness value of Ra < 0.1 µm. The simulation-supported design of the process also makes it possible to manufacture the mould elements with high dimensional and shape accuracy. In direct comparison to erosion processes, which are frequently used in the production of filigree elements in hardened steels, the micro milling process eliminates the need for time-consuming post-processing. In addition, a local adaptation of the friction conditions by bionic and technological structures could be successfully realized, whereby the surface structuring can be connected by micromilling to the production of mould elements using the same micromilling tools and the same clamping.

The local adaptation of friction and the controlled material flow through surface structures will be further analyzed in the next project phase. In order to achieve the maximum effect through surface structures, different variants in contiguity to each other may be necessary. Since these differ significantly in shape and size, discontinuous transitions can occur in the adjacent areas. Here it can be assumed that these have a negative effect on the friction and wear behaviour. The results of wear tests show the highest wear of the structures, especially in the area of sharp tool edges. Within the scope of the third project phase it is planned to develop strategies for continuous transition areas between varying structures. In addition, it is necessary to realize an adapted structuring of cavities and mould edges which show a reduced development of wear.

Furthermore, the generation of NC programs for the micromilling of structures has to be made more efficient and effective. By linking and repeating NC paths for individual structural elements to form networks, restrictions can be exceeded with regard to the number of structures resulting from CAD/CAM systems. A further development of algorithms, which are used to distort NC paths, will also be used to realize an automated adaptation of the structure to curved surfaces. In order to increase the efficiency of the micromilling process, it is also planned to investigate a cutting edge preparation of VHM micromilling tools. Preliminary investigations that have already been carried out provide results that promise both a longer tool life and better process planning reliability.

In addition, in the third phase it is planned to extend micromilling by wet-jet chip removal processes. It is planned to use wet-blasting processes for the post-treatment of PVD hard coatings (TP B5) and DLC coatings (TP B4) in order to reduce the surface roughness after the coating process and thus improve the tribological effect of the coating. In addition, wet-blasting has to be investigated with regard to the adjustment of residual compressive stresses in areas that are difficult to access, such as small cavities. Changes in the edge zone must also be analysed in connection with the reinforcement process of the forming tools.


Working Groups


Publications

    2019

    • Behrens, B.; Biermann, D.; Menzel, A.; Tillmann, W.; Krimm, R.; Meijer, A.; Schewe, M.; Stangier, D.; Commichau, O.; Müller, P.; Rosenbusch, D.: Untersuchungen strukturierter Werkzeugflächen und der Einfluss auf den Werkzeugverschleiß. In: 4. Industriekolloquium Blechmassivumformung 2019 - DFG Transregio 73 (Hannover, 12.03.2019), (2019), in print
    • Biermann, D.; Meijer, A.; Michel, S.; Jaeger, J.P.: Optimierung zerspanender Prozesse in kleinsten Dimensionen. In: maschinenbau - Das Schweizer Industriemagazin, (2019)5, Zürich: Olympa-Verlag AG, pp. 18-21

    2018

    • Krebs, E.; Wolf, M.; Biermann, D.; Tillmann, W.; Stangier, D.: High-quality cutting edge preparation of micromilling tools using wet abrasive jet machining process. In: Production Engineering, 12(2018), pp. 45-51
    • Meijer, A.; Krebs, E.; Wiederkehr, P.; Biermann, D.: Prediction of Feed-Rate Slowdowns in Precise Micromilling Processes. In: Journal of Manufacturing and Materials Processing, 2(2018)1, doi: 10.3390/jmmp2010019: MDPI, published
    • Biermann, D.; Meijer, A.; Krebs, E.; Michel, S.; Jaeger, J.: Neue Entwicklungen für den produktiven Einsatz von Hartmetallwerkzeugen in kleinsten Dimensionen. In: Herbert Danninger, Lorenz Sigl, Christoph Broeckmann (Edt.): Pulvermetallurgie - Neue Herausforderungen und neue Wege, 34(2018), Dortmund: Heimdall, pp. 135-155
    • Biermann, D.; Meijer, A.; Ott, A.: Präparation von Mikrofräswerkzeugen aus Vollhartmetall mit elastisch gebundenen Schleifkörpern. In: Hans-Werner Hoffmeister, Berend Denkena (Edt.): Jahrbuch Schleifen, Honen, Läppen und Polieren: Verfahren und Maschinen, 65(2018), Essen: Vulkan Verlag, pp. 80-92

    2017

    • Tillmann, W.; Stangier, D.; Lopes-Dias, N.-F.; Biermann, D.; Krebs, E.: Adjustment of Friction by Duplex-Treated, Bionic Structures for Sheet-Bulk Metal Forming. In: Tribology International, 111(2017), pp. 9–17
    • Sieczkarek, P.; Wernicke, S.; Gies, S.; Tekkaya, A.; Krebs, E.; Wiederkehr, P.; Biermann, D.; Tillmann, W.; Stangier, D.: Improvement strategies for the formfilling in incremental gear forming processes. In: Production Engineering, 11(2017)6, pp. 623-631

    Presentations

      2019

      • 11.03.2019: Commichau, O.: Untersuchungen strukturierter Werkzeugflächen und der Einfluss auf den Werkzeugverschleiß, Hannover
      • 15.05.2019: Meijer, A.: Mikrozerspanung von gehärtetem Schnellarbeitsstahl, Aachen

      2018

      • 24.08.2018: Meijer, A.: Mikrozerspanung - Von der Simulation des Materialabtrages bis zur intelligenten Fabrik, Dortmund
      • 28.08.2018: Wiederkehr, P.; Meijer, A.: Mikrozerspanung von bionischen Oberflächenstrukturen zur tribologischen Optimierung von Umformprozessen, Bochum
      • 28.11.2018: Meijer, A.: Prozessgestaltung für die Strukturierung von Freiformflächen durch Replikation und Verzerrung von Teilbereichen des NC-Programms, École Normale Supérieure Paris-Saclay, Cachan, FR
      • 29.11.2018: Biermann, D.: Neue Entwicklungen für den produktiven Einsatz von Hartmetallwerkzeugen in kleinsten Dimensionen, Hagen