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  • 1.
    Asnafi, Nader
    Örebro University, School of Science and Technology.
    3D Metal Printing from an Industrial Perspective: Product Design, Production and Business Models2018Conference paper (Refereed)
    Abstract [en]

    This paper summarizes the current position of 3D metal printing/additive manufacturing (henceforth called 3D metal printing) from an industrial perspective. The new possibilities to design the part differently simply because the new shape can be produced and which provides benefits with respect to improved material utilization degree, reduced weight, size etc. are addressed in this paper. Different types of generative design concepts such as form synthesis, topology optimization and lattice and surface optimization are exemplified. Low volume production by 3D metal printing is discussed. High volume production by 3D metal printing of manufacturing tools and dies is described.

    Tool & die production is an important phase in the development of new components/product models. This phase determines both the lead time (Time-To-Production/-Market) and the size of the investments required to start the production. The lead time for the production of tools and dies for a new car body is currently about 12 months and needs to be reduced 40% by 2020. The lead time for injection molds for small and large series production must be reduced to 10 days and 4 weeks respectively. Lead time and cost-efficient metallic tools can be provided by 3D metal printing. This paper focuses on tools and dies for the manufacture of sheet metal & plastic components for the engineering, automotive and furniture industries. The paper includes Powder Bed Fusion (PBF). Digitalization through virtual tool & die design and optimization of the tool & die production combined with the PBF´s digital essence provides greater flexibility, better efficiency, tremendous speed, improved sustainability and increased global competitiveness.

    3D metal printing is expected to result in several changes in the supplier chain and generate new business models. The present paper describes some of the changes 3D metal printing has led to and is expected to result in within the engineering and automotive industry in Europe during the coming years.

  • 2.
    Asnafi, Nader
    Örebro University, School of Science and Technology.
    3D Metal Printing from an Industrial Perspective: Product Examples, Production and Business Models2018Conference paper (Refereed)
    Abstract [en]

    This paper summarizes the current position of 3D metal printing/additive manufacturing (henceforth called 3D metal printing) by the so-called Powder Bed Fusion (PBF) from an industrial perspective, particularly in Sweden.

    The new possibilities to design the part differently simply because the new shape can be produced and which provides benefits with respect to improved material utilization degree, reduced weight, size etc. are addressed in this paper.

    Tool & die production is an important phase in the development of new components/product models. This phase determines both the lead time (Time-To-Production/‐Market) and the size of the investments required to start the production. The lead time for the production of tools and dies for a new car body is currently about 12 months and needs to be reduced 40% by 2020. The lead time for injection molds for small and large series production must be reduced to 10 days and 4 weeks respectively. Lead time and cost-efficient metallic tools can be provided by 3D metal printing. This paper focuses on tools and dies for the manufacture of sheet metal & plastic components for the engineering and automotive industries.

    Digitalization through virtual tool & die design and optimization of the tool & die production combined with the PBF´s digital essence provides greater flexibility, better efficiency, tremendous speed, improved sustainability and increased global competitiveness.

    3D metal printing is expected to result in several changes in the supplier chain and generate new business models. The present paper describes some of the changes 3D metal printing has led to and is expected to result in within the engineering and automotive industry during the coming years.

  • 3.
    Asnafi, Nader
    Örebro University, School of Science and Technology.
    3D Metal Printing of Production Tools & Dies2018Conference paper (Refereed)
    Abstract [en]

    3D metal printing is of great interest for manufacturing of tools and dies for high volume production. It is possible to accomplish lead time reduction, tool and die weight saving, improved cycle time etc. The presentation deals primarily with Powder Bed Fusion as 3D printing method and describes 3D metal printing of tools & dies both scientifically and from an industrialization perspective. The presentation shows how far we have come in industrialization of 3D metal printing of tools & dies and what needs to be done to include 3D metal printing in the existing industrial systems and infrastructure.

  • 4.
    Asnafi, Nader
    Örebro University, School of Science and Technology.
    3D Printing / Additative Manufacturing from Product Creator and Tool Maker Perspectives in the Automotive Industry2016Conference paper (Other academic)
  • 5.
    Asnafi, Nader
    VA Automotive AB, Hässleholm, Sweden .
    3D-printning från produktskapares och verktygsmakares perspektiv2015Conference paper (Other academic)
  • 6.
    Asnafi, Nader
    Sapa Technology, Finspång (and Vetlanda), Sweden.
    Analytical modelling of the forces and pressures required in hydropiercing2000Report (Other academic)
  • 7.
    Asnafi, Nader
    Volvo Car Components Corporation/Industrial Development Centre, Olofström, Sweden.
    Analytical modelling of tube hydroforming1999In: Thin-walled structures, ISSN 0263-8231, E-ISSN 1879-3223, Vol. 34, no 4, p. 295-330Article in journal (Refereed)
    Abstract [en]

    The automotive industry has shown a growing interest in tube hydroforming during the past years. The advantages of hydroforming (less thinning, a more efficient manufacturing process etc.) can, for instance, be combined with the high strength of extra high strength steels, which are usually less formable, to produce structural automotive components which exhibit lower weight and improved service performance. Design and production of tubular components require knowledge about tube material behaviour and tribological effects during hydroforming and how the hydroforming operation itself should be controlled. These issues are studied analytically in the present paper. Hydroforming consists of free forming and calibration. Only the so-called free forming is treated here. The analytical models constructed in this paper are used to show what the limits are during the free forming, how different material and process parameters influence the loading path and the forming result, and what an experimental investigation into hydroforming should focus on. The present study was a part of a larger investigation, in which finite-element simulations and experiments were also conducted. The results of these simulations and experiments will be accounted for in coming papers.

  • 8.
    Asnafi, Nader
    Volvo Car Corporation, Göteborg (and Olofström), Sweden.
    Automotive Tools & Dies - Volvo Cars Perspective2007Conference paper (Other academic)
  • 9.
    Asnafi, Nader
    Sapa Technology, Finspång (and Vetlanda), Sweden .
    Automotive Tubular Hydroforming: Fundmentals and Industrial Practice2000Conference paper (Other academic)
  • 10.
    Asnafi, Nader
    VA Automotive AB, Hässleholm, Sweden .
    Automotive/Car Body Stamping Tools & dies: 3D Printing Offers Shorter Lead Time and Reasonable Costs2016Conference paper (Other academic)
  • 11.
    Asnafi, Nader
    Jönköping University, Jönköping, Sweden .
    Development of Sustainable Products and Manufacturing/Production2014Conference paper (Other academic)
  • 12.
    Asnafi, Nader
    Örebro University, School of Science and Technology.
    Digitalization of the Swedish Industry2018Conference paper (Refereed)
  • 13.
    Asnafi, Nader
    Örebro University, School of Science and Technology.
    Digitalization of the Swedish Industry2018Conference paper (Refereed)
  • 14.
    Asnafi, Nader
    Luleå University of Technology, Luleå, Sweden .
    Formbarhet under dragpressning, sträckpressning och bockning samt egenskaper efter formning av aluminiumplåt1988Report (Other academic)
  • 15.
    Asnafi, Nader
    Volvo Car Corporation, Göteborg (and Olofström), Sweden .
    Forming of Aluminium2002Conference paper (Other academic)
  • 16.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden.
    Hydroformability of Extra High Strength Steels in Structural Tubular Applications: an Analysis based on Literature Survey1997Report (Other academic)
  • 17.
    Asnafi, Nader
    Örebro University, School of Science and Technology.
    Improved Lightweight Manufacturing Flexibility by Stamping of Selectively Laser Heat Treated Boron Steel Sheet2016Conference paper (Other academic)
  • 18.
    Asnafi, Nader
    Örebro University, School of Science and Technology.
    Innovative Lead Time and Cost Efficient Tools and Dies for Lightweight Autobody Components2016Conference paper (Other academic)
  • 19.
    Asnafi, Nader
    Uddeholms AB, Hagfors, Sweden .
    Kunddriven produktutveckling på en varierad marknad för global framgång2012Conference paper (Other academic)
  • 20.
    Asnafi, Nader
    Volvo Car Corporation, Göteborg (and Olofström), Sweden .
    Manufacturing the car body of tomorrow2002Conference paper (Other academic)
  • 21.
    Asnafi, Nader
    Örebro University, School of Science and Technology.
    Metal Additive Manufacturing/3D Metal Printing in the Circular Economy2018Conference paper (Refereed)
  • 22.
    Asnafi, Nader
    Volvo Car Corporation, Göteborg (and Olofström), Sweden .
    Nya material och processer vid framtagning av lättviktskarosser2004Conference paper (Other academic)
  • 23.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden .
    On Prediction of the Yield Strength of Pressed Panels by Using the Tensile Behaviour of the Virgin Material1992Conference paper (Other academic)
  • 24.
    Asnafi, Nader
    Gränges Technology, Finspång, Sweden.
    On springback of double-curved autobody panels2001In: International Journal of Mechanical Sciences, ISSN 0020-7403, E-ISSN 1879-2162, Vol. 43, no 1, p. 5-37Article in journal (Refereed)
    Abstract [en]

    The springback of double curved autobody panels is studied theoretically and experimentally. Both steel and aluminum sheets are included in this investigation. The obtained results show that the springback is decreased with increasing binder force, increasing curvature, increasing sheet thickness and decreasing yield strength. This paper comprises also a discussion on the plastic strains and their influence on the springback.

  • 25.
    Asnafi, Nader
    Industrial Development Center/Volvo Cars Body Components, Olofström, Sweden .
    On Springback of Double-Curved Autobody Panels1998In: Proceedings, working groups meeting - IDDRG, International Deep Drawing Research Group: Genval, Benelux, June 15 - 16, 1998, 1998Conference paper (Other academic)
  • 26.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden.
    On Springback of Double-Curved Autobody Panels, Part I: Theoretical Treatment1996Report (Other academic)
  • 27.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden.
    On Springback of Double-Curved Autobody Panels, Part II: Experimental Analysis1996Report (Other academic)
  • 28.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden .
    On strength, stiffness and dent resistance of car body panels1995In: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 49, no 1-2, p. 13-31Article in journal (Refereed)
    Abstract [en]

    There are cases in which practitioners wish to be able to predict the properties of a panel, should they replace one material by another. In this study, the yield strength, stiffness and dent resistance of double-curvature car body panels are treated both theoretically and experimentally. The results of the investigation show that the above-mentioned properties of a pressed panel can be predicted provided that the magnitude of the principal surface strains and the magnitude of the panel radii at the panel centre are known.

  • 29.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden.
    On Strength, Stiffness and Dent Resistance of Car Body Panels1993Report (Other academic)
  • 30.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden.
    On Strength, Stiffness and Dent Resistance of Car Body Panels1993Conference paper (Other academic)
  • 31.
    Asnafi, Nader
    Gränges Technology, Finspång, Sweden.
    On stretch and shrink flanging of sheet aluminium by fluid forming1999In: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 96, no 1-3, p. 198-214Article in journal (Refereed)
    Abstract [en]

    In this investigation, vertical stretch and shrink flanging of sheet aluminium by fluid forming are studied experimentally and theoretically. The theoretical part comprises both analytical modelling and finite-element simulations.

    The fracture limit in stretch flanging is determined by the plastic strain ratio, the strain hardening exponent, and the uniform strain. The greater the magnitude of these parameters, the greater will be the fracture limit.

    The maximum applied pressure determines the ’wrinkling’ limit in shrink flanging by fluid forming. The greater is this pressure, the greater ’wrinkling’ limit. This limit is certainly several times greater in magnitude than that in shrink flanging by conventional tools (a rigid punch and die).

  • 32.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden.
    On Stretch and Shrink Flanging of Sheet Aluminium by Fluid Forming1996Report (Other academic)
  • 33.
    Asnafi, Nader
    Industrial Development Center/Volvo Cars Body Components, Olofström, Sweden .
    On Stretch and Shrink Flanging of Sheet Aluminium by Fluid Forming1998In: Proceedings, working groups meeting - IDDRG, International Deep Drawing Research Group: Genval, Benelux, June 15 - 16, 1998, 1998Conference paper (Other academic)
  • 34.
    Asnafi, Nader
    Industrial Development Centre, Olofström, Sweden.
    On tool stresses in cold heading of fasteners1999In: Engineering Failure Analysis, ISSN 1350-6307, E-ISSN 1873-1961, Vol. 6, no 5, p. 321-335Article in journal (Refereed)
    Abstract [en]

    In this investigation, attention was focused on the tool stresses that emerge during manufacturing of fasteners. These stresses were studied both experimentally and theoretically. The theoretical part comprised finite-element simulation. This simulation showed that the zone at the die insert profile radius is so heavily loaded that plastic deformation is initiated in this region. In the experimental part, the emerging strains were measured in the region close to the interface between the die insert and the stress ring. The correspondence is good between the theoretical and experimental strains in this region. In spite of this and although 20 fasteners were cold-forged, the die insert did not fracture. Forming at production facilities showed that the die insert cracked after 9080 parts were produced. The results obtained in this investigation and the test conducted at production facilities indicate that high cycle fatigue, and not monotomic rupture, is the main cause of tool fracture in practice.

  • 35.
    Asnafi, Nader
    Örebro University, School of Science and Technology.
    Proceedings of the 2nd International Conference on Material Engineering and Advanced Manufacturing Technology (MEAMT 2018)2018Conference proceedings (editor) (Refereed)
  • 36.
    Asnafi, Nader
    Volvo Car Corporation, Göteborg (and Olofström), Sweden .
    Proceedings of the IDDRG 2008 Conference: Best in class stamping, 16-18 June 2008, Olofström, Sweden2008Conference proceedings (editor) (Other academic)
  • 37.
    Asnafi, Nader
    Örebro University, School of Science and Technology.
    Proceedings of the International Conference on Mechanical, Electric and Industrial Engineering (MEIE2018)2018Conference proceedings (editor) (Refereed)
  • 38.
    Asnafi, Nader
    Volvo Car Corporation, Göteborg (and Olofström), Sweden.
    Proceedings of the international conference on recent advances in manufacture & use of tools & dies and stamping of steel sheets: October 5-6, 2004, Olofström, Sweden2004Conference proceedings (editor) (Other academic)
  • 39.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden.
    Springback & Fracture in V-Die Bending: A Literature Survey of Analytical Models1996Report (Other academic)
  • 40.
    Asnafi, Nader
    Gränges Technology, Finspång, Sweden.
    Springback and fracture in v-die air bending of thick stainless steel sheets2000In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 21, no 3, p. 217-236Article in journal (Refereed)
    Abstract [en]

    In this investigation, the attention is focused on the springback and fracture of thick stainless steel sheets. Nine different stainless grades and various thickness are tested. The thinnest sheet is 7.9 mm, whilst the thickest sheet is 31.3 mm. A consistent analytical model is constructed for prediction of the springback, the inner sheet radius prior to and after unloading, and the smallest die width. The springback calculated by this analytical model is in all cases smaller than that found experimentally. The correspondence between theory and practice, is however, very good, although the shift in the position of the neutral axis and thinning are neglected in the theoretical analysis. Fracture did not occur in any of the conducted bending operations. It is commonly assumed that fracture in v-die bending is related to the reduction in the cross-section area at fracture, Z, in tensile testing. Z was greater than 70% for the majority of the studied materials. It is shown that particularly the mode of fracture (fracture through shear bands or by necking) should be studied in future investigations.

  • 41.
    Asnafi, Nader
    VA Automotive AB, Hässleholm, Sweden .
    Sustainable Product and Production Development2015Conference paper (Other academic)
  • 42.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden.
    The Influence of In-Process Variation of Blank Holding Force on Deep-Drawability1995In: Leading-Edge Manufacturing Strategies for the Metalforming Industry, Richmond Heights, Ohio, USA: PMA , 1995, p. 965-976Conference paper (Other academic)
  • 43.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden.
    The Influence of In-Process Variation of Blank Holding Force on Deep-Drawability1993Report (Other academic)
  • 44.
    Asnafi, Nader
    Örebro University, School of Science and Technology.
    The Second International Conference on Mechanical, Electric and Industrial Engineering, 25–27 May 2019, Hangzhou, China2019Conference proceedings (editor) (Refereed)
  • 45.
    Asnafi, Nader
    Uddeholms AB, Hagfors, Sweden.
    The tool and die materials research and innovation agenda2013In: International Heat Treatment and Surface Engineering, ISSN 1749-5148, Vol. 7, no 3, p. 101-105Article in journal (Refereed)
  • 46.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden.
    Tool Design in Cold Heading of Fasteners, Part I: Literature Survey and Analytical Modelling1995Report (Other academic)
  • 47.
    Asnafi, Nader
    Swedish Institute for Metals Research, Stockholm, Sweden.
    Tool Design in Cold Heading of Fasteners, Part II: Finite Element Simulations and Experimental Analysis1996Report (Other academic)
  • 48.
    Asnafi, Nader
    Uddeholms AB, Hagfors, Sweden .
    Tooling & Technologies for Processing Ultra High Strength Materials2011Conference paper (Other academic)
  • 49.
    Asnafi, Nader
    Volvo Car Corporation, Göteborg (and Olofström), Sweden .
    Tooling in manufacturing of car bodies: today & tomorrow2002Conference paper (Other academic)
  • 50.
    Asnafi, Nader
    Uddeholms AB, Hagfors, Sweden .
    Tools & Dies for Processing of Advanced High Strength Sheet Steels2011Conference paper (Other academic)
12 1 - 50 of 90
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