Dieless drawing

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Scheme of the procedure with heating and cooling elements

Dieless Drawing (DLD), German and free lengths or amorphous or tool-free [ wire or bar ] Pull , different from the conventional pull in that the tool is dispensed with and in place of the Ziehhols (drawing die) delivers a heater which heats the material and thus makes it flow under the external load. This contactless warm or hot process is mainly of interest in wire drawing for special products and belongs to the tensile forming process group .

Research history

The beginnings of the development of the process go back to Weiss and Kot (1969), who carried out the first experiments with steel and titanium on a converted lathe . The topic was worked on experimentally and numerically, mainly from the 1970s in China and Japan. Attempts have been made in Japan to use the method for industrial application in the production of barrel-shaped automobile springs. At the Max Planck Institute for Iron Research in Düsseldorf, the topic was worked on theoretically and experimentally in parallel.

methodology

Process variant with movable heating and cooling device

In this process, the heating, measuring and cooling unit (HMK) has no mechanical contact with the workpiece, but causes it to flow through heating, which reduces the diameter under the applied tension, after which it is cooled down again to the solid state. The heating module typically works inductively , other heating elements are also possible, e.g. for non-conductors, and experiments have also been carried out with lasers and ultrasound .

The main advantage of this process is that it is easy to change the wire diameter, as there is no tool change (set-up time). In addition, with the flexible forming zone, it is possible to produce wire with a diameter that changes over its length, to achieve greater reductions in one forming step, or to manufacture non-circular cross-sections or pipes and the like. In addition, the material properties can be thermomechanically influenced by the heating / cooling conditions.

These advantages are offset by the slow process speed, in particular a pronounced susceptibility to interference and high demands on the control so that it does not lead to an error in the end shape change or to a constriction with subsequent breakage . A description of the stationary forming process is not sufficient; the dynamic flow processes and the material properties that change with temperature must also be taken into account.

literature

  • Klaus von Eynatten: Dieless Drawing: A massive forming process for the flexible adjustment of shape, structure and mechanical properties of long products. Diss.ETH Zurich No. 15443, 2004, doi : 10.3929 / ethz-a-004725803 ( pdf , e-collection.library.ethz.ch; also in Association of German Engineers VDI: Progress Reports , Series 2, Production Technology , Edition 649, 2004 , ISBN 978-318364902-0 ).
  • A. Kolling: Development of a process model for the free length of bars. Dissertation. Umformtechnische Schriften , Shaker Verlag, Aachen 1997, ISBN 3-8265-2335-0 .
  • Klaus Schmeißer: Laboratory studies on the free lengths of bars (dieless drawing). Volume 80 of Umformtechnische Schriften , Shaker Verlag, Aachen 1998, ISBN 978-382653691-5 .
  • H. Sekiguchi, K. Kobatake, K. Osakada: Dieless drawing processes. In: J Jpn Soc Technol Plast 17 (180), 1976, pp. 67-71.
  • H. Sekiguchi, K. Kobatake: Development of the dieless drawing process. In: Advanced Technology of Plasticity , Vol. 1, 1987, pp. 347-353.
  • P. Tiernan, MT Hillery: Dieless wire drawing — an experimental and numerical analysis. In: J Mater Process Technol. 155-156 (2004), pp. 1178-1183.
  • P. Tiernan, MT Hillery: An analysis of wire manufacture using the dieless drawing method. In: Journal of Manufacturing Processes , Volume 10, Issue 1, January 2008, pp. 12-20 ( Abstract , sciencedirect.com).

Individual evidence

  1. ↑ Lit. Eynatten 2004, 1.2 Motivation p. 4 (pdf p. 18).
  2. ^ V. Weiss, R. Kot: Dieless wire drawing with transformation plasticity. In: Wire J. , 1969, (9), p. 182.
  3. ↑ cf. JM Alexander, TW Turner: A preliminary investigation of the dieless drawing of titanium and some steels. In: Proceedings of the 15th MTDR 1974, p. 525.
  4. ↑ z. E.g. H. Sekiguchi, K. Kobatake, K. Osakada: A fundamental study on dieless drawing. In: Proceedings of the 15th MTDR 1974, p. 539.
  5. ↑ a b c d Lit. Eynatten 2004, 1. Introduction , especially Principle of Dieless Drawing, p. 1 ff (pdf p. 15 ff).
  6. ↑ z. E.g .: Yonggang Li, Nathaniel R. Quick, Aravinda Kar: Dieless laser drawing of fine metal wires. In: J Mater Process Technol 123 (2002), pp. 451-458.
  7. ↑ z. E.g .: X. Shan, H. Qi, L. Wang, T. Xie: A new model of the antifriction effect on wiredrawing with ultrasound. In: Int J Adv Manuf Technol 63 (2012), pp. 1047-1056.
  8. ↑ z. E.g .: Yeong-Maw Hwang, Tsung-Yu Kuo: Dieless drawing of stainless steel tubes. In: The International Journal of Advanced Manufacturing Technology. Volume 68, Issue 5, September 2013, pp. 1311-1316, doi : 10.1007 / s00170-013-4922-0 .