TPT March 2014

Article

Tracto-Technik GmbH & Co KG

Torsion factor 1

Torsion factor 2

Torsion factor 3

Figure 4: The torsion factor describes the component’s geometry with regard to deformation due to torsion [6]

certain bending part, taking into account the bending part’s geometry and the manufacturing limitations of the bending method at the same time. Suggestions and validation of the criteria by industry are considered. By transferring the research results of this project into a national or international standardisation process the criteria should become industry standards. Overall acceptance of the standards is the prerequisite and can be used for increasing the application possibilities of tube and profile bending parts. Actual and future work deals with the categorisation of the big range of different bending processes and their variations and tool setups. The design of a detailed catalogue which includes the performance of each process is now worked out. This project receives financial support by the German Federal Ministry of Economics and Technology according to a decision of the German Federal Parliament. [1] Inkrementelles Schwenkbiegen zur kostengünstigen Herstellung von Trägerstrukturen in Elektrofahrzeugen. Forschungsverbundprojekt beim BMWi im Rahmen der Ausschreibung ELEKTRO POWER [2] Burkhardt, B.: Enger geht es kaum. In: Blech Rohre Profile 10 (2008), S. 28-29, Meisenbach GmbH Verlag, Bamberg [3] Engel, B: Was geht beim Rohrbiegen, In: Blech, Rohre, Profile, 04 (2009), Meisenbach GmbH Verlag, Bamberg [4] Rohrmann, Michael: Grundlagen des Rohrbiegens – Ein Einführung in die Rohrbiegetechnologie. TRACTO-TECHNIK GmbH, Lennestadt 2005 [5] Engel, B; Kuhnhen, C; Mathes, C; Kersten, S; Hermes, M; Pleul, C; Becker, C; Gerlach, C; Rohrmann, M; Tekkaya, A E (2012): Neuer Standard vereinfacht Auslegung von Rohren und Profilen. In: Maschinenmarkt (10), Vogel Verlag, S. 26-27 [6] Kuhnhen,C:Kategorisierung vonBiegebauteilen füreinen Industriestandard., In: 32. Verformungskundliches Kolloquium (23.02.-26.03.2013), Lehrstuhl für Umformtechnik, Montanuniversität Leoben, Leoben, 2013 [7] VDI 3430.: Rotationszugbiegen von Profilen, Beuth Verlag, Berlin, 2012 [8] Groche, P; Schmoeckel, D: Kundenspezifische Kaltprofile durch flexibles Walzprofilieren. In: Reinhart, G; Zäh, M F: Marktchance Individualisierung – Festschrift zum 60. Geburtstat von Prof. Milberg. Springer Verlag, Berlin 2003 [9] Hermes, M: Neue Verfahren zum rollenbasierten 3D-Biegen von Profilen. Shaker, Herzogenrath 2012 [10] Imkamp, D; Schmitt, R, Berthold, J: Blick in die Zukunft der Fertigungsmesstechnik – Die VDI/VDE-GMA Roadmap Fertigungsmesstechnik 2020, In: tm – Technisches Messen 79 (2012) 10, Oldenbourg Wissenschaftsverlag, S. 433-439 References

The key issue is to consider the changing distances between the alterable inside diameter of the tube and the outside diameter of the mandrel, which supports the tube during the bending process and prevents the bend from collapsing. Much more complex is the bending of “tailored profiles”, because in that case special adaptations of all bending tools have to be applied. Due to high competitive pressure the quality of the finished bending parts is crucially important to succeed in the global market. Special quality criteria ensure that the tendency towards constant rise of customer and quality requirements is taken into account when selecting a specific bending process [10, p.433] . The criterion shape and positional tolerances defines the permissible deviation of the bending part compared with its reference geometry. Category 1 allows considerable deviations, which could probably be realised by most of the bending methods. Category 2 presupposes closer tolerances, which are usually obtainable by all semi-finished parts whose tolerances are within the standards. Category 3 describes high dimensional accuracies with adherence to very close tolerances. This category therefore requires a thorough evaluation of the eligible bending method(s) as well as selection of semi-finished parts which meet the highest demands where tight tolerances regarding the geometrical dimensions are concerned. After the bending products of category 3 need often a hydroforming calibration. Semi-finished parts with high-quality surfaces are crucially important particularly in terms of tube and profile assembling as visible parts. In order to consider this when selecting a bending method, the surface factor describes allowable damages or deviations of the bending part’s surface. The surface factor is also classified into three categories, starting with allowable deviations from the reference surface quality (eg deep scratches and grooves as well as geometrical deviations at the inside curve) over minor deviations without any technical or functional losses up to a flawless surface. Commercialisation and follow-up of the research results The criteria for categorisation of bending performances introduced above allow a sufficiently clear description of tube and profile bending parts in regard to their production complexity. During the course of the project the criteria are being further developed and refined. Based on these criteria it is possible to pre-select an optimum bending method for a

Tracto-Technik GmbH & Co KG – Germany Email: tubomat@tracto-technik.de Website: www.tracto-technik.com

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March 2014