Beneficial effect of stress superposition on damage reduction in trimming processes
WEIß Alexander, FELDE Alexander, LIEWALD Mathias, ZERFAß Helmutdownload PDF
Abstract. Trimming processes are frequently used for the manufacturing of fastener heads and similar parts with high precision requirements for specific regions of the part. Compared to conventional cold forging processes, the desired geometry can be achieved with significantly lower forces. However, trimming of sharp-edged geometries often leads to a highly inhomogeneous material flow and stress state in the workpiece, resulting in crack formation at such edges. To address this shortcoming, superposition of compressive stresses can be used to reduce the damage in the trimming process significantly. In this paper, the beneficial effect of stress superposition on damage reduction in a trimming process of a splined part is presented. By means of a numerical investigation using the FE-software DEFORM 3D, the impact of compressive stress superposition on the damage respectively crack formation at the edges of a splined part was investigated. Afterwards, trimming dies were manufactured and experimental investigations with three different trimming die geometries and different preform geometries were conducted to manufacture the splined parts. The edges of the splined parts were then characterized with a digital microscope and compared to the numerical results.
Stress Superposition, Trimming, Damage Reduction, Crack Formation
Published online 4/19/2023, 10 pages
Copyright © 2023 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA
Citation: WEIß Alexander, FELDE Alexander, LIEWALD Mathias, ZERFAß Helmut, Beneficial effect of stress superposition on damage reduction in trimming processes, Materials Research Proceedings, Vol. 28, pp 611-620, 2023
The article was published as article 66 of the book Material Forming
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 K. Lange, M. Kammerer, K. Pöhlandt, J. Schöck, 2008, Fließpressen – Wirtschaftliche Fertigung metallischer Präzisionswerkstücke, Springer-Verlag Berlin Heidelberg, ISBN: 9783540309093.
 E. Doege, B.-A. Behrens, Handbuch Umformtechnik. Grundlagen, Technologien, Maschinen, 2010. https://doi.org/10.1007/978-3-662-43891-6
 M. Liewald, A. Weiß, A. Felde, Prozessgrenzen beim Angraten unrunder und asymmetrischer Geometrien, Final report of GCFG-study, German Cold Forging Group, 2021.
 C. MacCormack, Finite Element Analysis & Die Profile Optimisation for a Cold Forging Process, PhD Thesis, University of Dublin, Trinity College, Ireland, 2000.
 C. MacCormack, J. Monaghan, Failure analysis of cold forging dies using FEA, J. Mater. Process. Technol. 117 (2001) 209–215. https://doi.org/10.1016/S0924-0136(01)01139-6
 C. MacCormack, J. Monaghan, A finite element analysis of cold-forging dies using two- and three-dimensional models, J. Mater. Process. Technol. 118 (2001) 286–292. https://doi.org/10.1016/S0924-0136(01)00960-8
 J. Petruska, J. Borkovec, J. Hulka, R. Foret, Application of ductile fracture criteria to industrial cutting processes, Adv. Mater. Res. 264–265 (2011) 913–918. https://doi.org/10.4028/www.scientific.net/AMR.264-265.913
 J. Borkovec, J. Petruska, Evaluation of four fracture criteria in compressive loading conditions, Postępy w Inżynierii Mechanicznej (eng. Developments in Mechanical Engineering) 1 (2013) 19–28.
 S.C. Park, D.H. Lee, D.C. Ko, B.M. Kim, M.H. Kim, K.H. Lee, Integrated process design of Al6061 alloy bolts for fastening offshore platforms, J. Mech. Sci. Technol. 33 (2019) 3695–3707. https://doi.org/10.1007/s12206-019-0711-5
 F. Kocatürk, B. Tanrıkulu, S. Doğan, C. Kılıçaslan, S. Yurtdaş, U. İnce, Optimization of trimming process in cold forging of steel bolts by Taguchi method, Int. J. Pressure Vessel. Piping 194 (2021) 104503. https://doi.org/10.1016/j.ijpvp.2021.104503
 Schuler, Metal Forming Handbook, Springer-Verlag Berlin Heidelberg New York This, 1998, https://doi.org/10.1007/978-3-642-58857-0, ISBN: 3540611851
 A. Felde, S. Rudolf, M. Liewald, Enhancement of Process Limits in Cold Extrusion, New Developments in Forging Technology, 2009, pp. 293–309. ISBN: 9783883553757
 S. Rudolf, Beitrag zur Erweiterung der Verfahrensgrenzen des Quer-Fließpressens, Institute for Metal Forming Technology, University of Stuttgart, 2014. ISBN: 9783883554044
 J. Wälder, M. Liewald, Hollow Lateral Extrusion of Tubular Billets – Further Development of the Cold Forging Process, Appl. Mech. Mater. 794 (2015) 160–165. https://doi.org/10.4028/www.scientific.net/AMM.794.160
 O. Hering, A. Dunlap, A.E. Tekkaya, A. Aretz, A. Schwedt, Characterization of damage in forward rod extruded parts, Int. J. Mater. Form. 13 (2020) 1003–1014. https://doi.org/10.1007/s12289-019-01525-z
 A. Franceschi, J. Stahl, C. Kock, R. Selbmann, S. Ortmann-Ishkina, A, Jobst, M. Merklein, B. Kuhfuß, M. Bergmann, B.-A. Behrens, W. Volk, P. Groche, Strategies for residual stress adjustment in bulk metal forming, Arch. Appl. Mech. 91 (2021) 3557–3577. https://doi.org/10.1007/s00419-021-01903-7