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B2 - Micro Elements (funding period 2)

Machining of molds with filigree structures for Sheet-Bulk metal forming

Project Status: finished

Last Update: 23.01.2017


In the subproject B2 the manufacturing of dies for SBMF is investigated. The main focus is placed on the manufacturing of complex and filigree form elements as well as on the manufacturing of functional surface structures using micromilling processes. In the first project phase, fundamental investigations on the feasibility of micromachining of hardened high speed steels (> 60 HRC) were carried out with tools diameter of d ≤ 1 mm. It was shown that using a suitable selection of cutting parameters and tools a high process reliability can be achieved even with tool diameters of d = 0.2 mm. Based on the generated knowledge, the production of bionic structures (see subproject B5) was optimized, which has been already successfully tested in real forming processes. Fig. 1 illustrates a structured tooth tool for the incremental forming process (see subproject A4).

Fig. 1: Micromilling of surface structures on tooth tool for incremental forming processes

In the second project phase, the fundamental investigations and surface structuring are continued. During the fundamental investigations, a stronger focus is placed to the simulation-based process planning. For this purpose, the geometric-kinematic milling simulation has to be further developed for micromilling. Based on geometrically calculated data, the engagement situation is analyzed and used for the evaluation of a NC program.

For this purpose, Fig. 2 shows some functionalities of the simulation on the example of the manufacturing a die for SBMF (more details in Fig. 3) which are currently in the development. The colour coded NC paths visualize in this case the height of the process forces based on the defined tolerances according to experimental investigations. Basically, it is also possible to analyze other values which are calculable during the simulation like impulses, uncuted chip thickness, volume, contact time etc. Additionally, they can be calculated for local engagement situations as for entire NC programs. Furthermore, Fig. 2 shows the real uncuted chip thickness from a selected (current) engagement situation.

Fig. 2: Offline evaluation of the micromilling process based on the simulated uncuted chip thickness and a colour coded NC paths with the regard to the process force

Fig. 3 illustrates machined results of die manufacturing. The finishing of all die segments was carried out with only one ball-end milling cutter and one end milling cutter. By using suitable cutting parameters the tool wear was considerably, thus, no significant differences in the surface quality were measured. The results show a surface roughness of Ra < 0.2 µm across all die segments even on the convex shape. Furthermore, almost no burr formation was achieved on the functional surfaces, so that a post-processing of the die was not necessary.

Fig. 3: Roughness profile of the machined die

For the investigations of the functional surface structures it is necessary to expand the range of complexity of the structures and to analyze them in laboratory experiments and evaluate their advantages in real forming processes. In these investigations two different approaches are considered. Firstly, the manufacturing of bionic motivated structures is analyzed in cooperation with the TP B5. Secondly, technological structures are developed which are inspired by the advantages of the micromilling process so that the manufacturing can be particularly effective.


Working Groups



    • Kersting, P.; Gröbel, D.; Merklein, M.; Sieczkarek, P.; Wernicke, S.; Tekkaya, A.; Krebs, E.; Freiburg, D.; Biermann, D.; Weikert, T.; Tremmel, S.; Stangier, D.; Tillmann, W.; Matthias, S.; Reithmeier, E.; Löffler, M.; Beyer, F.; Willner, K.: Experimental and numcerial analysis of tribological effective surfaces for forming tools in Sheet-Bulk Metal Forming. In: Production Engineering, 10(2016)1, Springer, pp. 37-50
    • Löffler, M.; Engel, U.; Schulte, R.; Gröbel, D.; Krebs, E.; Freiburg, D.; Biermann, D.; Stangier, D.; Tillmann, W.; Weikert, T.; Wartzack, S.; Tremmel, S.; Lucas, H.; Denkena, B.; Merklein, M.: Tribological measures for controlling material flow in sheet-bulk metal forming. In: Production Engineering, 10(2016), pp. 459-470


    • Kersting, P.; Krebs, E.; Odendahl, S.; Simone Carmignato; Filippo Zanini; Tobias Siebrecht: Analysing machining errors resulting from a micromilling process using CT measurement and process simulation. In: 4M/ICOMM15 Annoni, A.; Fassi, I.; Wiens, G.J; Dimov, S. (Hrsg.) (Edt.): Proceedings of the 4M/ICOMM2015 Conference, (2015), pp. 137-140
    • Landkammer, P.; Söhngen, B.; Loderer, A.; Krebs, E.; Steinmann, P.; Willner, K.; Hausotte, T.; Kersting, P.; Biermann, D.: Experimentelle Verifizierung eines Benchmark-Umformprozesses. In: Tekkaya, A. E.; Liewald, M.; Merklein, M.; Behrens, B.-A (Edt.): Tagungsband zum 18. Workshop Simulation in der Umformtechnik & 3. Industriekolloquium Blechmassivumformung 2015 - DFG Transregio 73, (2015), Aachen: Shaker Verlag, pp. 91-110
    • Landkammer, P.; Loderer, A.; Krebs, E.; Söhngen, B.; Steinmann, P.; Hausotte, T.; Kersting, P.; Biermann, D.; Willner, K.: Experimental verification of a benchmark forming simulation. In: Key Engineering Materials, 639(2015), pp. 251-258
    • Lucas, H.; Denkena, B.; Grove, T.; Krebs, E.; Kersting, P.; Freiburg, D.; Biermann, D.: Analysis of Residual Stress States of Structured Surfaces Manufactured by High-Feed and Micromilling. In: HTM Journal of Heat Treatment and Materials, 70(2015)4, pp. 183-189
    • Stangier, D.; Tillmann, W.; Krebs, E.; Kersting, P.; Biermann, D.; Hagen, L.: Wear Behavior of Bio-inspired and Technologically Structured HVOF Sprayed NiCrBSiFe Coatings. In: Surface and Coatings Technology, 280(2015), pp. 16-26
    • Tillmann, W.; Stangier, D.; Biermann, D.; Kersting, P.; Krebs, E.; Hagen, L.: Tribological investigation of bionic and micro-structured functional surfaces. In: Materialwissenschaft und Werkstofftechnik, 46(2015)11, pp. 1096-1104


    • Krebs, E.; Kersting, P.: Improving the cutting conditions in the five-axis micromilling of hardened high-speed steel by applying a suitable tool inclination. In: Procedia CIRP, 14(2014), pp. 366-370
    • Biermann, D.; Kersting, P.; Odendahl, S.; Joliet, R.; Zabel, A.: Simulation der NC-Fräsbearbeitung – Multiskaliger Ansatz für eine effiziente und flexible Simulation147(2014)6, WB – Werkstatt und Betrieb, pp. 78-81
    • Kersting, P.; Krebs, E.; Baumann, J.; Joliet, R.; Odendahl, S.; Rausch, S.; Schweinoch, M.; Siebrecht, T.: Potentiale geometrisch-physikalischer Prozesssimulationen zur Modellierung und Optimierung spanender Fertigungsverfahren. In: Begleitband zum Fertigungstechnischen Kolloquium Magdeburg – Moderne Fertigungstechnologien zur Steigerung von Leistung, Qualität und Effizienz, (2014), pp. 4: 1 - 12


    • Vierzigmann, U.; Schneider, T.; Koch, J.; Merklein, M.; Engel, U.; Hense, R.; Biermann, D.; Krebs, E.; Kersting, P.; Lucas, H.; Denkena, B.; Herper, J.; Tillmann, W.; Stangier, D.: Untersuchungen von Tailored Surfaces für die Blechmassivumformung mittels angepasstem Ringstauchversuch. In: Merklein, M.; Behrens, B. A., Tekkaya, A. E. (Edt.): 2. Workshop Blechmassivumformung, (2013), Bamberg: Meisenbach, pp. 137-162
    • Kersting, P.; Odendahl, S.: Higher Efficiency Modeling of Surface Location Errors by Using a Multi-scale Milling Simulation 9(2013), Procedia CIRP, pp. 18-22
    • Sieczkarek, P.; Kwiatkowski, L.; Tekkaya, A.; Krebs, E.; Kersting, P.; Tillmann, W.; Herper, J.: Innovative tools to improve incremental bulk forming processes. In: Key Engineering Materials , 554(2013), pp. 1490-1497
    • Biermann, D.; Krebs, E.; Steiner M.: Investigation of Different Hard Coatings for Micromilling of Austenitic Stainless Steel. In: Procedia CIRP, 7(2013), pp. 246-251
    • Krebs, E.: Mikrofräsen von funktionalen Oberflächenstrukturen in hochharten Arbeitsstählen. In: Biermann, D. (Hrsg.) (Edt.): Begleitband zum Fachgespräch zwischen Industrie und Hochschule „Zerspanen im modernen Produktionsprozess“, (2013), pp. 189-199



      • 08.03.2016: Krebs, E.; Biermann, D.: Aktuelle Entwicklungen um Zerspanprozesse auf Hochleistungswerkstoffe einzustellen, Nürtingen


      • 11.05.2015: Tillmann, W.; Stangier, D.; Biermann, D.; Kersting, P.; Krebs, E.: Surface modification by means of multilayer systems and micromilling technology, Long Beach USA


      • 24.06.2014: Biermann, D.; Krebs, E.; Kersting, P.: Laserunterstütztes Mikrotiefbohren und Mikrofräsen zur Strukturierung von Oberflächen, 11. MST-Regionalkonferenz Dortmund
      • 15.07.2014: Kersting, P.: Simulating Machining Processes Using Geometrical and Physically Based Models, CIRP RA Workshop, Gjovik, Norwegen
      • 28.08.2014: Kersting, P.: Separation of Process and Machine Influences in Micro Milling – Experiments, Simulation and Metrology, CIRP General Meeting, CWG on Micro-Production Engineering, Nantes, Frankreich


      • 27.02.2013: Krebs, E.: Spanende Fertigung von Formwerkzeugen mit filigranen Strukturen für die Blechmassivumformung, Hagen
      • 23.04.2013: Sieczkarek, P.; Kwiatkowski, L.; Tekkaya, A.; Krebs, E.; Kersting, P.; Tillmann, W.; Herper, J.: Innovative tools to improve incremental bulk forming processes, ESAFORM Conference 2013, Aveiro, Portugal
      • 11.09.2013: Krebs, E.: Mikrofräsen funktionaler Oberflächenstrukturen in hochharten Arbeitsstählen, Dortmund
      • 13.11.2013: Koch, J.: Untersuchung von Tailored Surfaces für die Blechmassivumformung mittels angepasstem Ringstauchversuch, Erlangen