Axial feed cross rollers

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The axial feed transverse rollers (AVQ) is a variant of Querkeilwalzens for producing multiple stepped, undulating components in the field of small and medium quantities. When cross rolling, according to DIN 8583-2, the rolling stock is rotated around its own axis without moving in the axial direction. "With axial feed cross-rolling, the workpiece is moved axially and the roll is adjusted radially."

Procedural principle

The AVQ thus represents a modification of the so-called convex-convex cross wedge rolling, whereby the wedge angle required to realize the axial material flow is not part of the tool geometry, but is formed kinematically by the freely selectable ratio ß of the axial workpiece speed and the peripheral speed of the roller or workpiece .

The driven rolling tools are moved towards each other in the radial direction, as a result of which a workpiece arranged slightly below the center in the roll gap is set in rotation by frictional engagement. With further radial roll feed, a groove in the shape of the roll profile is rolled into the workpiece. If the rotating workpiece is now pulled out of the roll gap via the rotatable clamping device in the direction of the workpiece axis, the rolled-in groove is widened. Depending on the direction of a further radial roll feed, the next shaft shoulder with a smaller or larger diameter can be rolled. This kinematic creation of shape is what makes the process flexible.

This means that rotationally symmetrical, stepped or profiled workpieces can be manufactured in a flexible, automated manner by means of forming, which makes it possible to economically manufacture smaller numbers of such workpieces. In addition to the large variety of contours that can be produced for the workpieces, other advantages include the improved - especially dynamic - strength of the rolled parts, the considerable savings in material compared to complete turning and the reduction in production time - despite (if necessary) machining.

Development history

During the studies on cross wedge rolling carried out at the professorship for production engineering / forming technology at the TU Dresden under the direction of Ludwig Eberlein at the end of the 1970s , it turned out to be a deficiency that no ready-to-use working parameters were available. The large number of rolling tools with different wedge angles required to determine them led to the proposal to kinematically map the axial material flow caused by the forming wedge during cross wedge rolling by the axial displacement of the tools or the workpiece. This process principle of the AVQ was patented in 1983. The process was initially intended as an alternative to the conventional, pure machining production of multiple stepped, wave-shaped parts made of solid material .

As part of a DFG research project “Process maps for axial feed cross rolling”, a pilot system for the AVQ was developed and built on the basis of a two-slide profile rolling machine in the early 1990s. In an extensive test program at the TU Dresden and through complex and detailed FEM process analyzes at the Institute for Forming Technology and Forming Machines (IFUM) of the University of Hanover , the main influencing variables of this highly transient cross-rolling process and their effects on the rolling process were determined under the direction of Wolfgang Voelkner and Eckart Doege and the result was examined using the example of a solid shaft for a gear manufacturer. Research work and a. FEM simulations of the AVQ were carried out in the 2000s at the Beijing Research Institute of Mechanical and Electrical Technology . At the Hanover Fair in 1996, the rolling process and the associated pilot system were presented to a wide audience in accordance with the state of development at that time.

In the following years, principally on behalf of research institutions and industrial companies such as Volkswagen AG, principle tests on the AVQ for special applications and different materials, i.e. H. various alloys of ferrous and non-ferrous metals, including materials that are difficult to form and highly heat-resistant. For example, the production was of preforms for forged vehicle wheels of magnesium - alloys studied by AVQ.

AVQ of hollow parts

The sharp rise in material costs and the trend towards lightweight construction led to considerations in 2002 to also use axial feed cross-rolling for the production of hollow shafts with defined outer and inner contours. However, previous investigations came to the conclusion that hollow parts can only be manufactured economically using AVQ with a defined outer contour, especially when the parts are very long. The use of profile mandrels for rolling a defined inner contour was discarded, as this limits the flexibility - one of the most important advantages of the AVQ. With the AVQ without a mandrel, on the other hand, there is an "unhindered" flow of material in the inner diameter of the pipe used as the starting material, which in any case requires machining to achieve a defined inner contour.

Rolling attempts to make the AVQ flexible also with a mandrel led to a process variant patented in cooperation with ThyssenKrupp, including an associated device that enables the rolling of stepped hollow shafts of various dimensions and even greater lengths from a tube with a few simple tools. The tests have shown that it is possible to manufacture tubular stabilizers for motor vehicles with two frontally offset areas and a long middle section with reduced diameter and wall thickness from a tube in one setting.

Machine development

The first test machines at the TU Dresden were modified profile rolling machines of various sizes from Profiroll Technologies GmbH Bad Düben. The last prototype machine was scrapped in 2012.

Based on the process principle and the machine solutions developed for this purpose, an AVQ machine was designed and built by LASCO Umformtechnik GmbH for the Fraunhofer Institute for Machine Tools and Forming Technology (IWU) Chemnitz . This AVQ 630 machine was presented to the public in November 2012 as part of the 4th International Conference “Accuracy in Forming Technology” (ICAFT).

The machine at the IWU is used to further develop the AVQ for research into the manufacture of engine and engine parts as well as medical products (e.g. hip joint prostheses ) made of titanium aluminides as part of the BMBF research project "Resource-efficient shaping processes for titanium and high-temperature alloys". In the context of this research project, the work on the FEM simulation of the incremental forming process AVQ was continued.

Web links

Individual evidence

  1. ↑ Jochen Dietrich, Heinz Tschätsch: Practice of forming technology . Forming and cutting processes, tools, machines. 11th edition. Springer, 2013, ISBN 978-3-658-01995-2 , pp. 155 ff .
  2. ↑ Eckart Doege, Bernd-Arno Behrens: Handbook of forming technology . Basics, technologies, machines. Springer, 2006, ISBN 3-540-23441-1 , pp. 513 .
  3. ↑ Jochen Dietrich, Helmut Müller: A contribution to the exploration and evaluation of forming processes using the example of concave-convex cross rolling . Dissertation A. Technical University of Dresden, 1978.
  4. ↑ Ludwig Eberlein, Helmut Müller: Results and goals of the scientific cooperation in rolling . In: Umformtechnik . tape 22 , no. 3 , 1988, pp. 106-111 .
  5. ↑ a b Patent DD214310A1 : Device for cross-rolling rotationally symmetrical workpieces. Registered on March 22, 1983 , published October 10, 1984 , inventor: Helmut Müller. ‌
  6. ^ A b Wolfgang Voelkner, Thomas Ficker, Mario Houska: Development of new processes for rolling rod-shaped and ring-shaped parts . In: Proceedings of the Saxon Conference on Forming Technology . Freiberg 1995.
  7. ^ A b Mario Houska, Marius-Ioan Rotarescu: Experimental and Finite-Element Analysis of Axial Feed Bar Rolling (AVQ) . In: Proceeding of the 6th ICTP . Nuremberg 1999.
  8. ↑ Marius-Ioan Rotarescu, Mario Houska: Friction conditions during axial feed cross rolling . In: Umformtechnik . tape 33 , no. 2 . Meisenbach Verlag, Bamberg 1999, p. 42-46 .
  9. ↑ CG Xu, GH Liu, GS Ren, Z. Shen, CP Ma, WW Ren: FINITE ELEMENT ANALYSIS OF AXIAL FEED BAR ROLLING . In: Acta Metall. Sin. (Engl. Lett.) . tape 20 , no. 6 . Elsevier Ltd., 2007, ISSN  1006-7191 , p. 463-468 .
  10. ↑ Mario Houska, Dieter Berger, Uwe Thonig, Ingrid Zimmermann: Das Axialvorschubquerwalzen . Video production for Hanover Fair 1996. Technical University of Dresden, 1995 ( online ).
  11. ↑ Andreas Löffler: Characterization of the forming behavior of wrought magnesium alloys for forged vehicle wheels . Dissertation. Technical University Hamburg-Harburg, 2008.
  12. ↑ Thomas Ficker, Andre Hardtmann: Development of the axial feed cross rolling at the TU Dresden - a historical overview from the beginning of the 1970s until today . In: UTF Science . No. II / 2012 . Meisenbach Verlag, 2010 ( ringwalzen.de [PDF]). PDF ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.ringwalzen.de
  13. ↑ Patent DE102007041149B3 : Method and device for cross-rolling stepped hollow shafts or cylindrical hollow parts from a tube. Registered on August 30, 2007 , published on April 2, 2009 , applicant: Technische Universität Dresden, ThyssenKrupp Bilstein Suspension GmbH Ennepetal, inventors: Hans Dziemballa, Lutz Manke, Mario Houska, Thomas Ficker, André Hardtmann. ‌
  14. ↑ Dietmar Kuhn: Lasco prototype works at the Fraunhofer Institute IWU. maschinenmarkt.de, February 7, 2013, accessed on February 19, 2013 .
  15. ↑ Bernd Lorenz: Closing poster "Resource-efficient shaping processes for titanium and high-temperature alloys". (PDF; 192 kB) Fraunhofer IWU Chemnitz, accessed on February 19, 2013 .
  16. ↑ Bernd Lorenz: Final report "Resource-efficient shaping processes for titanium and high-temperature alloys". (PDF; 23 MB) Fraunhofer IWU Chemnitz, August 30, 2013, accessed on July 9, 2014 .
  17. ^ V. Güther, St. Erxleben, P. Janschek, U. Hirnschal, Bernd Lorenz: Resource-efficient shaping processes for titanium and high-temperature alloys . In: Proceedings Symposium Raw Material Efficiency and Raw Material Innovations 2011 . Fraunhofer Verlag, Nuremberg 2011, ISBN 978-3-8396-0222-5 ( r-zwei-innovation.de [PDF]).
  18. ^ Markus Bergmann, André Wagner, Jürgen Steger and Bernd Lorenz: Contribution to the numerical simulation of incremental massive forming processes . In: Infostelle Industrieverband Massivumformung e. V. (Ed.): SchmiedeJOURNAL . No. 03 . Hagen 2013, p. 28–31 ( massivumformung.de [PDF; 601 kB ; accessed on April 9, 2013]).
  19. ↑ Stefan Gärtz: Influence of the process parameters in axial feed cross rolling on the component geometry . Master thesis. Chemnitz University of Technology, Chemnitz 2016.
  20. ↑ Nadine Schubert, Jürgen Steger: Reshaping complex geometries in small series. maschinenmarkt.de, April 23, 2018, accessed on April 23, 2018 .