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Improved Sheet Bulk Metal Forming Processes by Local Adjustment of Tribological Properties

Title data

Hetzner, Harald ; Koch, Johannes ; Tremmel, Stephan ; Wartzack, Sandra ; Merklein, Marion:
Improved Sheet Bulk Metal Forming Processes by Local Adjustment of Tribological Properties.
In: Journal of Manufacturing Science and Engineering. Vol. 133 (9 December 2011) Issue 6 . - Art.Nr. 061011.
ISSN 1528-8935
DOI: https://doi.org/10.1115/1.4005313

Project information

Project financing: Deutsche Forschungsgemeinschaft

Abstract in another language

This paper is focused on a combined deep drawing and extrusion process dedicated to the new process class of sheet bulk metal forming (SBMF). Exemplified by the forming of gearings, combined sheet and bulk forming operations are applied to sheet metal in order to form local functional features through an intended and controlled change of the sheet thickness. For investigations on the form filling and the identification of significant influencing factors on the material flow, a FE simulation model has been built. The FE model is validated by the results of manufacturing experiments using DC04 with a thickness of 2.0 mm as blank material. Due to the fact that the workpiece is in extensive contact to the tool surface and that the pressure reaches locally up to 2500 MPa, the tribological conditions are a determining factor of the process. Thus, their influence is discussed in detail in this paper. In the first instance, different frictional zones having a distinct effect on the resulting material flow are identified and their effect on improved form filling is demonstrated. Subsequently, a more comprehensive methodology is developed to define tribological zones of forming tools. For this, a system analysis of the digital mock-up of the forming process is performed. Besides friction, other relevant aspects of forming tool tribology like contact pressure, sliding velocity, and surface magnification are considered. The gathered information is employed to partition the tools into tribological zones. This is done by systematically intersecting and re-merging zones identified for each of the criterion. The so-called load-scanning test allows the investigation of the friction coefficient in dependence of the contact pressure and possible loading limits of tribological pairings. It provides an appropriate tribological model test to evaluate tribological measures like coatings, surface textures and lubricants with respect to their targeted application in particular zones. The obtained results can be employed in the layout of further forming processes to reach the desired process behavior. This can be, for example, an improved form filling, less abrasive wear and adhesive damage or lower forming forces, respectively tool load for an improved durability of the die.

Further data

Item Type: Article in a journal
Refereed: Yes
Keywords: load-scanning test; material flow; sheet bulk metal forming; tribology
Institutions of the University: Faculties > Faculty of Engineering Science > Chair Engineering Design and CAD
Profile Fields > Advanced Fields > Advanced Materials
Profile Fields > Emerging Fields > Energy Research and Energy Technology
Result of work at the UBT: No
DDC Subjects: 600 Technology, medicine, applied sciences > 620 Engineering
Date Deposited: 21 Sep 2020 10:58
Last Modified: 21 Sep 2020 10:58
URI: https://eref.uni-bayreuth.de/id/eprint/57059