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  • 1.
    Anderberg, Staffan
    University West, Department of Engineering Science, Division of Production Engineering.
    A study of process planning for metal cutting2009Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Process planning as a function for competitiveness is often neglected. However, as an intermediary between product development and manufacturing, it holds a key function in transforming product specifications and requirements into a producible process plan. Demands and requirements should be met concurrently as manufacturing costs and lead times are minimised. The focus of this thesis is the act of process planning, where the use of better methodologies, computer-aids and performance measurements are essential parts. Since process planning has the function of transforming demands and requirements, changing customer and regulative requirements are vital to regard. Since environmentally benign products and production increases in importance, the research presented in this thesis includes a CNC machining cost model, which relates machining costs to energy consumption.  The presented results in this thesis are based on quantitative and qualitative studies in the metal working industry.

     

    This thesis has contributed to an enhanced understanding of process planning to achieve better performance and important areas for improvements. Despite a 50 year history of computerised process planning aids, few of these are used in the industry, where manual process planning activities are more common. Process planning aids should be developed around the process planner so that non-value adding activities, such as information management and documentation are minimised in order to allow more resources for value adding activities, such as decision making. This thesis presents a study of systematic process planning in relation to perceived efficiency. This correlation could however not be verified, which opens up for further studies of other possible explanations for process planning efficiency. Process planning improvements in the industry are difficult to make, since there is little focus on process planning activities and limited knowledge about actual performance hereof. This means that measures taken regarding process planning development are difficult to verify.

  • 2.
    Anderberg, Staffan
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Beno, Tomas
    University West, Department of Engineering Science, Division of Production Engineering.
    Pejryd, Lars
    3Production Technology Centre, Innovatum AB.
    A survey of metal working companies’ readiness for process planning performance measurements2009In: IEEE International Conference on Industrial Engineering and Engineering Management, IEEM 8-11 sep, 2009, Hong-Kong, 2009, p. 1910-1914Conference paper (Refereed)
    Abstract [en]

    The paper presents an investigation regarding the potential and the readiness for implementing performance indicators and performance measurement systems of the process planning work for metal working companies. The paper is based on a questionnaire survey distributed to process planners in the Swedish metal working industry. The main outcome of the investigation is a foundation for understanding the implementation of performance measures of the process planning work for CNC machining. The survey revealed a few strengths and short comings in the studied companies.

  • 3.
    Anderberg, Staffan
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Beno, Tomas
    University West, Department of Engineering Science, Division of Production Engineering.
    Pejryd, Lars
    Production Technology Centre, Innovatum AB.
    CNC machining process planning productivity – a qualitative survey2009In: Proceedings of The International 3'rd Swedish Production Symposium, SPS 09, 2009, p. 228-235Conference paper (Refereed)
    Abstract [en]

    Process planning is the link between design and manufacturing and consequently an important function, since it influences many of the company objectives. However, many companies have little knowledge about their process planning function and the efficiency is thus not optimal. The paper focuses on the automation level of process planning as a mean to improve process planning efficiency. Six CNC machining companies was interviewed and accordingly analysed through a five dimensional automation level model to understand their process planning work. The main findings are that the automation level is low and concurrent engineering is lacking in many of the investigated companies.

  • 4.
    Anderberg, Staffan
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Beno, Tomas
    University West, Department of Engineering Science, Division of Production Engineering.
    Pejryd, Lars
    University West, Department of Engineering Science, Division of Production Engineering.
    Energy and Cost Efficiency in CNC Machining from a Process Planning Perspective2011In: 9th Global Conference on Sustainable Manufacturing: Sustainable Manufacturing –Shaping Global Value Creation / [ed] Günther Seliger, 2011, p. 383-389Conference paper (Refereed)
    Abstract [en]

    The role of process planning as an enabler for cost efficient and environmentally benign CNC machining is investigated in the paper. Specific energy is used as the principal indicator of energy efficient machining and different methods to calculate and estimate this is exemplified and discussed. The interrelation between process planning decisions and production outcome is sketched and process capability can be considered as one factor of green machining. A correlation between total machining cost and total energy use was shown for an experimental case. However, to generalise conclusions, the importance of having reliable data during process planning to make effective decisions should not be underestimated.

  • 5.
    Anderberg, Staffan
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Beno, Tomas
    University West, Department of Engineering Science, Division of Production Engineering.
    Pejryd, Lars
    University West, Department of Engineering Science, Division of Production Engineering.
    Process planning for cnc machining of swedish subcontractors: A web survey2014In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 17, p. 732-737Article in journal (Refereed)
    Abstract [en]

    Process planning of CNC machining is critical to ensure cost, time and quality parameters of manufacturing operations. At the heart of process planning is, typically the process planner, who must make a multitude of decisions regarding machines, cutting strategies, tools and process parameters etc. Today there are a number of different tools and methods available to aid the process planner. This paper explores today’s industrial use of some of these aids and outlinespotential underlying reasons for the current state. The empirical data is based on a questionnaire survey of Swedish CNC machining sub-contractors. The main conclusion is that despite a long history of development of various aids (CAD/CAM, PLM standards etc.) there is still a large proportion of the industry, which has not yet adopted these aids. By the responding companies 32% do not use any CAM system and only 2% use a PLM system. On the other side of the spectrum is a group of 25% that uses CAM in 75% or more of their planned products. The learning from this survey can be used to better understand the industrial needs and focus research and development efforts.

  • 6.
    Anderberg, Staffan
    et al.
    University West, Department of Technology, Mathematics and Computer Science, Division for Mechanical Engineering.
    Beno, Tomas
    University West, Department of Engineering Science, Division of Production Engineering.
    Pejryd, Lars
    University West, Department of Engineering Science, Division of Production Engineering.
    Production preparation methodology in Swedish metal working industry - a State of the Art investigation2008In: Swedish Production Symposium, Stockholm 18-20 November 2008. Proceedings: The Swedish Production Academy's annual conference / [ed] Bengt Lindberg och Johan Stahre, Stockholm: The Swedish Production Academy , 2008, p. 443-450Conference paper (Other academic)
    Abstract [en]

    This article presents a brief state of the art in the Swedish metal working industry regarding the production preparation process for the machine centre. The article is based on a relationship model from which a questionnaire was developed. The model incorporates the perceived preparation process efficiency, the amount of systematic preparation work, in relation to the companies’ premises as possible causes. The investigation is based on a general hypothesis that a more systematic approach in the preparation process leads to higher preparation process efficiency. This hypothesis was supplemented by two more hypotheses and additional analyses to create an understanding of the situation. The main finding in this investigation is that there appear to be no relationship between increased  ystematic preparation work and perception of higher preparation efficiency. The investigation also indicates that many metal working companies have little knowledge about the performance of their preparation process and that there is an efficiency improvement potential of nearly 30%.

  • 7.
    Anderberg, Staffan
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Kara, Sami
    University of New South Wales.
    Energy and cost efficiency in CNC machining2009In: The 7th CIRP Conference on Sustainable Manufacturing: Chennai, India, December 2-4, 2009., 2009Conference paper (Refereed)
    Abstract [en]

    General cost for CNC machining and the associated energy cost are set in the context of making economic and environmental improvements. This creates an incentive for manufacturing companies to investigate the energy efficiency of manufacturing processes. The paper presents a costing model, based on machining experiments. The model is accompanied with an industry based case to estimate the cost savings. The results show that substantial cost savings with respect to energy efficiency is unlikely, since energy costs in CNC machining comprises a small cost component. However significant cost savings can be achieved if the production output is increased as a consequence from higher material removal rates due to optimised machining parameters.

  • 8.
    Anderberg, Staffan
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Kara, Sami
    University of New South Wales.
    Beno, Tomas
    University West, Department of Engineering Science, Division of Production Engineering.
    Impact of energy efficiency on computernumerically controlled machining2010In: Proceedings of the Institution of mechanical engineers. Part B, journal of engineering manufacture, ISSN 0954-4054, E-ISSN 2041-2975, Vol. 224, no B4, p. 531-541Article in journal (Refereed)
    Abstract [en]

    Increasing environmental demands from governmental bodies and customers stress the importance of companies improving their environmental performance. The research presented here shows that productivity and cost efficiency improvements can be achieved alongside energy savings in a computer numerically controlled machining environment. This improves the profitability of the companies, but also leads them towards more sustainable and environmentally aware manufacturing; the relationship between machining parameters, machining costs, and energy consumption is evaluated. From this perspective, it is important that production planners etc. understand the methodological possibilities for improvements in cost and energy efficiency. The current research is based on a machining cost model and experiments where energy consumption and tool wear were monitored.

  • 9.
    Andersson, Johan
    University West, Department of Engineering Science, Division of Production Engineering.
    Utvärdering och förbättring gällande Volvo Aeros tillämpning av metodiken praktisk problemlösning2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Volvo Aero develops, designs, manufactures and performs maintenance of engine and related components for civil and military aircrafts. The vision is to deliver world-leading transport solutions through continuous improvement and long term business deployment, which for the daily work means systematic problem solving through the methodology practical problem solving, whose origin is Toyota.

    The purpose of this thesis was to examine whether Volvo Aero’s approach of practical problem solving was simple, systematic and guided, which from Toyota’s point of view creates sound conditions for effective problem solving.

    Initially, Toyota’s attitude and behaviour towards problem solving was described from the point of view of The Toyota Way. Thereafter, a literature study on practical problem solving was completed. Furthermore, a pilot study was carried out where Volvo Aero’s approach to practical problem solving was applied to an organisational problem. The pilot study was evaluated and areas for improvements were identified where the methodology was difficult, indistinct and inadequate guided. Finally, improvements were proposed regarding Volvo Aero’s approach to practical problem solving, which was scientifically anchored to Toyota.

    • Defining and analysing the symptoms brings understanding for the causes of the problem
    • Quantifying the present condition and the expected illustrates the magnitude of the problem
    • Appears the root cause to be clear is probably the countermeasure obvious
    • A considerable approach using Plan-Do-Check-Act (PDCA) provides an effective and strong tool for continuous improvement

    The improvements were proposed with purpose to simplify Volvo Aero’s methodology and to support and guide the user, which creates sound conditions for effective problem solving and provides opportunities for daily use that foster continuous improvement.

  • 10.
    Azar, Amin S.
    et al.
    SINTEF Mat & Chem, Oslo, Norway.
    Svensson, Lars-Erik
    University West, Department of Engineering Science, Division of Production Engineering.
    Nyhus, Bård
    SINTEF Mat & Chem, Oslo, Norway.
    Effect of crystal orientation and texture on fatigue crack evolution in high strength steel welds2015In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 77, p. 95-104Article in journal (Refereed)
    Abstract [en]

    In the present study, electron backscattered diffraction is used to analyze the fatigue crack evolution in a high strength steel weld that was loaded cyclically in the plastic regime. Three prominent regions of a fatigue crack are investigated separately: crack tip, crack trajectory and crack initiation. Taylor and Schmid factors are mapped with respect to the defined loading matrix. Possible effective mechanisms are proposed based on the local plasticity properties like lattice rotation and misorientation. The analyses of the crack tip and trajectory regions show that although the critical resolved shear stresses in some regions are low, small deformation resistance of these regions can compromise the dislocation immobility and cause local fracture. It is shown that if the crack grows transgranularly, at least one side of the crack may show low lattice rotation or strain equivalent values, which indicates the relaxation of elastic stresses after fracture. The crack initiation is determined to be dominantly controlled by transcrystalline mechanism of initiation that takes place under plastic loading conditions. It is also shown that the secondary < 123 >11 (1) over bar type of slip systems were the most activated under such loading conditions. (C) 2015 Elsevier Ltd. All rights reserved.

  • 11.
    Bahbou, M. Fouzi
    et al.
    University West, Department of Technology, Mathematics and Computer Science, Division for Mechanical Engineering.
    Nylén, Per
    University West, Department of Engineering Science, Division of Production Engineering.
    Barbezat, G.
    Sulzer Metco, Wohlen, Switzerland .
    A parameter study of the Protal® Process to optimise the adhesion of Ni5Al Coatings2004In: Thermal Spray 2004 : Advances in technology and applications: Proceedings of the International Thermal Spray Conference 10-12 May 2004, Osaka, Japan Thermal Spray 2004, 2004, p. 898-902Conference paper (Refereed)
    Abstract [en]

    The Protal process combines surface preparation using a laser and thermal spraying in one production step. The laser preparation is based on a photomechanical reaction induced by the interaction between a laser of high instantaneous power and a polluted surface. The mechanism of bonding and the coating-substrate interface are then changed in comparison with grit blasting resulting in a significantly reduced substrate roughness. This study is aimed at finding the optimal Protal process parameters for the coating adhesion of a Ni5%Al sprayed on Ti6Al4V and IN718 alloys. The parameters investigated are laser beam intensity, the time delay between the laser impact and the spray impact, powder feed rate, substrate roughness and temperature. A test plan including these parameters is analysed by means of a fractional factorial design of experiment method. The adhesions of the coatings are measured using the ASTM C633 standard test. Data are analysed by a multiple linear regression model using a least squares fit. In addition, the coating/substrate interface is examined by optical and electron scanning microscopy (SEM) techniques as well as by Auger electron spectroscopy. Substrate roughness, substrate temperature and laser intensity are all shown to have a negative correlation with adhesion strength within the investigated range. Areas of diffusion are noticed at the coating/substrate interface.

  • 12.
    Battabyal, Manjusha
    et al.
    Chalmers University of Technology.
    Klement, Uta
    Chalmers University of Technology.
    Norell, Mats
    Chalmers University of Technology.
    Goutier, Simon
    University of Limoges.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Production Engineering.
    Comparison of microstructure in Ni-Al single splats and millimeter sized droplets2011In: Surface Modification Technologies XXV : Proceedings of the Twenty Fith International Conference on Surface Modification Technologies - SMT25: Trolhättan June 20-22, 2011, 2011, p. 3-12Conference paper (Refereed)
  • 13.
    Beno, Thomas
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Isaksson, Marina
    Pejryd, Lars
    University West, Department of Engineering Science, Division of Production Engineering.
    Investigation of Machining Greek Ascaloy with Minimal Quantity Lubrication Sustainable/Cleaner Manufacturing2008In: LCE 2008: 15th CIRP International Conference on Life Cycle Engineering: Conference Proceedings, Sidney, 17-19 March, 2008Conference paper (Refereed)
  • 14.
    Beno, Tomas
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Anderberg, Staffan
    University West, Department of Engineering Science, Division of Process and Product Development.
    Green machining: improving the bottom line2009Conference paper (Other academic)
    Abstract [en]

    The aim of this paper is to present how Green machining can be established in the metal working industry for taking immediate actions towards a more environmental friendly manufacturing, but also to address areas for research in order to advance towards a more sustainable manufacturing industry. An often overlooked approach is to use the knowledge about the specific cutting energy and its dependency upon machining parameters in order to establish a machining strategy that leads towards a more energy efficient production, but also contributes to increased productivity and thereby improving the bottom line as well. The paper has a production preparation perspective and thus presents the areas where a green machining strategy is applicable.

  • 15.
    Beno, Tomas
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Hulling, U
    Volvo Aero Corporation, Trollhättan.
    Measurement of cutting edge temperature in drilling2012In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 3, p. 531-536Article in journal (Refereed)
    Abstract [en]

    In this paper a methodology is described to conduct temperature measurement on the cutting edges and the clearance faces on twist drills using a fibre optic two color pyrometer. Two measuring positions of the fibre were used in order to determine the temperature at two different locations, centre and outer corner of the drill. The measurements were carried out on a stationary work piece and a rotating drill. The work piece materials ranged from tool steel, aged Inconel 718, Ti6-4 to carbon epoxy fibre composite. All experiments were conducted in dry machining conditions.© 2012 The Authors.

  • 16.
    Beno, Tomas
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Isaksson, Marina
    Pejryd, Lars
    University West, Department of Engineering Science.
    Machining aerospace material with sub-cooled minimal quantity cppling lubrication fluids2009In: World Tribology Congress 2009: Kyoto, Japan, September 6-11, 2009Conference paper (Other academic)
  • 17.
    Bolelli, G.
    et al.
    University of Modena and Reggio Emilia, Dipartimento di Ingegneria “Enzo Ferrari”, Via Pietro Vivarelli 10/1, I-41125 Modena (MO), Italy.
    Berger, L. -M
    Fraunhofer-Institut für Werkstoff- und Strahltechnik (IWS), Winterbergstr. 28, D-01277 Dresden, Germany.
    Börner, T.
    University of Modena and Reggio Emilia, Dipartimento di Ingegneria “Enzo Ferrari”, Via Pietro Vivarelli 10/1, I-41125 Modena (MO), Italy.
    Koivuluoto, H.
    Tampere University of Technology, Department of Materials Science, Korkeakoulunkatu 6, FI-33720 Tampere, Finland.
    Lusvarghi, L.
    University of Modena and Reggio Emilia, Dipartimento di Ingegneria “Enzo Ferrari”, Via Pietro Vivarelli 10/1, I-41125 Modena (MO), Italy.
    Lyphout, Christophe
    University West, Department of Engineering Science, Division of Production Engineering.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Production Engineering.
    Matikainen, V.
    Tampere University of Technology, Department of Materials Science, Korkeakoulunkatu 6, FI-33720 Tampere, Finland.
    Nylén, Per
    University West, Department of Engineering Science, Division of Production Engineering.
    Sassatelli, P.
    University of Modena and Reggio Emilia, Dipartimento di Ingegneria “Enzo Ferrari”, Via Pietro Vivarelli 10/1, I-41125 Modena (MO), Italy.
    Trache, R.
    Fraunhofer-Institut für Werkstoff- und Strahltechnik (IWS), Winterbergstr. 28, D-01277 Dresden, Germany.
    Vuoristo, P.
    Tampere University of Technology, Department of Materials Science, Korkeakoulunkatu 6, FI-33720 Tampere, Finland.
    Tribology of HVOF- and HVAF-sprayed WC-10Co4Cr hardmetal coatings: A comparative assessment2015In: Surface and Coatings Technology, ISSN 0257-8972, Vol. 265, p. 125-144Article in journal (Refereed)
    Abstract [en]

    his paper provides a comprehensive assessment of the sliding and abrasive wear behaviour of WC–10Co4Cr hardmetal coatings, representative of the existing state-of-the-art. A commercial feedstock powder with two different particle size distributions was sprayed onto carbon steel substrates using two HVOF and two HVAF spray processes.Mild wear rates of < 10-7 mm3/(Nm) and friction coefficients of ≈ 0.5 were obtained for all samples in ball-on-disk sliding wear tests at room temperature against Al2O3 counterparts. WC–10Co4Cr coatings definitely outperform a reference electrolytic hard chromium coating under these test conditions. Their wear mechanisms include extrusion and removal of the binder matrix, with the formation of a wavy surface morphology, and brittle cracking. The balance of such phenomena is closely related to intra-lamellar features, and rather independent of those properties (e.g. indentation fracture toughness, elastic modulus) which mainly reflect large-scale inter-lamellar cohesion, as quantitatively confirmed by a principal component analysis. Intra-lamellar dissolution of WC into the matrix indeed increases the incidence of brittle cracking, resulting in slightly higher wear rates. At 400 °C, some of the hardmetal coatings fail because of the superposition between tensile residual stresses and thermal expansion mismatch stresses (due to the difference between the thermal expansion coefficients of the steel substrate and of the hardmetal coating). Those which do not fail, on account of lower residual stresses, exhibit higher wear rates than at room temperature, due to oxidation of the WC grains.The resistance of the coatings against abrasive wear, assessed by dry sand–rubber wheel testing, is related to inter-lamellar cohesion, as proven by a principal component analysis of the collected dataset. Therefore, coatings deposited from coarse feedstock powders suffer higher wear loss than those obtained from fine powders, as brittle inter-lamellar detachment is caused by their weaker interparticle cohesion, witnessed by their systematically lower fracture toughness as well.

  • 18.
    Bolelli, G.
    et al.
    University of Modena and Reggio Emilia, Dipartimento di Ingegneria 'Enzo Ferrari', Via P. Vivarelli 10/1, Modena, MO, Italy .
    Berger, L.-M.
    Fraunhofer-Institut für Werkstoff- und Strahltechnik (IWS), Winterbergstr. 28, Dresden, Germany.
    Börner, T.
    Fraunhofer-Institut für Werkstoff- und Strahltechnik (IWS), Winterbergstr. 28, Dresden, Germany.
    Koivuluoto, H.
    Tampere University of Technology, Department of Materials Science, Korkeakoulunkatu 6, Tampere, Finland .
    Matikainen, V.
    Tampere University of Technology, Department of Materials Science, Korkeakoulunkatu 6, Tampere, Finland .
    Lusvarghi, L.
    University of Modena and Reggio Emilia, Dipartimento di Ingegneria 'Enzo Ferrari', Via P. Vivarelli 10/1, Modena, MO, Italy .
    Lyphout, Christophe
    University West, Department of Engineering Science, Division of Production Engineering.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Production Engineering.
    Nylén, Per
    University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Sassatelli, P.
    University of Modena and Reggio Emilia, Dipartimento di Ingegneria 'Enzo Ferrari', Via P. Vivarelli 10/1, Modena, MO, Italy .
    Trache, R.
    Fraunhofer-Institut für Werkstoff- und Strahltechnik (IWS), Winterbergstr. 28, Dresden, Germany .
    Vuoristo, P.c
    Tampere University of Technology, Department of Materials Science, Korkeakoulunkatu 6, Tampere, Finlan.
    Sliding and abrasive wear behaviour of HVOF- and HVAF-sprayed Cr3C2-NiCr hardmetal coatings2016In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 358-359, p. 32-50Article in journal (Refereed)
    Abstract [en]

    This paper provides a comprehensive characterisation of HVOF- and HVAF-sprayed Cr3C2–25 wt.% NiCr hardmetal coatings. One commercial powder composition with two different particle size distributions was processed using five HVOF and HVAF thermal spray systems.All coatings contain less Cr3C2 than the feedstock powder, possibly due to the rebound of some Cr3C2-rich particles during high-velocity impact onto the substrate.Dry sand-rubber wheel abrasive wear testing causes both grooving and pull-out of splat fragments. Mass losses depend on inter- and intra-lamellar cohesion, being higher (≥70 mg after a wear distance of 5904 m) for the coatings deposited with the coarser feedstock powder or with one type of HVAF torch.Sliding wear at room temperature against alumina involves shallower abrasive grooving, small-scale delamination and carbide pull-outs, and it is controlled by intra-lamellar cohesion. The coatings obtained from the fine feedstock powder exhibit the lowest wear rates (≈5x10−6 mm3/(Nm)). At 400 °C, abrasive grooving dominates the sliding wear behaviour; wear rates increase by one order of magnitude but friction coefficients decrease from ≈0.7 to ≈0.5. The thermal expansion coefficient of the coatings (11.08x10−6 °C−1 in the 30–400 °C range) is sufficiently close to that of the steel substrate (14.23x10−6 °C−1) to avoid macro-cracking

  • 19.
    Bonilla Hernández, Ana Esther
    et al.
    University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Beno, Tomas
    University West, Department of Engineering Science, Division of Production Engineering.
    Repo, Jari
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Wretland, Anders
    GKN Aerospace Engine Systems AB, Trollhättan, Sweden.
    Analysis of Tool Utilization from Material Removal Rate Perspective2015In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 29, p. 109-113Article in journal (Refereed)
    Abstract [en]

    An end of life strategy algorithm has been used to study a CNC program to evaluate how the cutting inserts are used in terms of their full utilization. Utilized tool life (UTL) and remaining tool life (RTL) were used to evaluate if the insert has been used to its limits of expected tool life, or contributing to an accumulated tool waste. It is demonstrated that possible means to improvement exists to increase the material removal rate (MRR), thereby using the insert until its remaining tool life is as close to zero as possible. It was frequently found that inserts were used well below their maximum performance with respect to cutting velocity.

  • 20.
    Carlsson, Henric
    et al.
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production Engineering.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Production Engineering.
    General Time Synchronisation Method for PLC Programs Aiming at Virtual Verification and Development2008In: 17th IFAC World: Congress Proceedings of the 17th World Congress. The International Federation of Automatic Control. Soel, July 6-11, 2008, p. 4440-4445Conference paper (Other academic)
    Abstract [en]

    The latest state-of-the-art Computer Aided Production Engineering (CAPE) simulation technology offers OPC integration for PLC verification. A critical drawback with this technology has been identified and described within this paper. A new time synchronisation method and a simulation architecture are therefore presented and proposed. The time synchronisation method together with the architecture can be used when verifying and developing real-time dependent control logic for industrial control system, e.g. PLC with CAPE tools. The method described in this paper is general and should work on any PLCs that are compatible with the IEC 61131-3 standard. A test case was also carried out, showing that by disregarding time synchronisation it is impossible to verify real-time dependent PLC functions together with CAPE tools in a reliable way. However, the test case also shows that by applying the proposed time synchronisation method together with the described simulation architecture a successful industrial verification method is achieved

  • 21.
    Cernuschi, F.
    et al.
    RSE – Ricerca per il Sistema Energetico, Via Rubattino, 54, 20134 Milano.
    Lorenzoni, L.
    RSE – Ricerca per il Sistema Energetico, Via Rubattino, 54, 20134 Milano.
    Capelli, S.
    RSE – Ricerca per il Sistema Energetico, Via Rubattino, 54, 20134 Milano.
    Guardamagna, C.
    RSE – Ricerca per il Sistema Energetico, Via Rubattino, 54, 20134 Milano.
    Karger, M.
    Forschungszentrum Jülich GmbH, Institut für Energieforschung IEF-1, 52425 Jülich.
    Vaßen, R.
    Forschungszentrum Jülich GmbH, Institut für Energieforschung IEF-1, 52425 Jülich.
    von Niessen, K.
    Sulzer Metco AG, Rigackerstr. 16, CH-5610, Wohlen.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Production Engineering.
    Menuey, J.
    Snecma, 1 Rue Maryse Bastié, 86100 Châtellerault.
    Giolli, C.
    Turbocoating SpA, Via Mistrali 7, Rubbiano di Solignano,.
    Solid particle erosion of thermal spray and physical vapour deposition thermal barrier coatings2011In: Wear, Vol. 271, no 11-12, p. 2909-2918Article in journal (Refereed)
    Abstract [en]

    Thermal barrier coatings (TBC) are used to protect hot path components of gas turbines from hot combustion gases. For a number of decades, in the case of aero engines TBCs are usually deposited by electron beam physical vapour deposition (EB-PVD). EB-PVD coatings have a columnar microstructure that guarantees high strain compliance and better solid particle erosion than PS TBCs. The main drawback of EB-PVD coating is the deposition cost that is higher than that of air plasma sprayed (APS) TBC. The major scientific and technical objective of the UE project TOPPCOAT was the development of improved TBC systems using advanced bonding concepts in combination with additional protective functional coatings. The first specific objective was to use these developments to provide a significant improvement to state-of-the-art APS coatings and hence provide a cost-effective alternative to EB-PVD. In this perspective one standard porous APS, two segmented APS, one EB-PVD and one PS-PVD™ were tested at 700°C in a solid particle erosion jet tester, with EB-PVD and standard porous APS being the two reference systems.Tests were performed at impingement angles of 30° and 90°, representative for particle impingement on trailing and leading edges of gas turbine blades and vanes, respectively. Microquartz was chosen as the erodent being one of the main constituents of sand and fly volcanic ashes. After the end of the tests, the TBC microstructure was investigated using electron microscopy to characterise the failure mechanisms taking place in the TBC.It was found that PS-PVD™ and highly segmented TBCs showed erosion rates comparable or better than EB-PVD samples. © 2011 Elsevier B.V.

  • 22.
    Charles, Corinne
    University West, Department of Engineering Science, Division of Production Engineering.
    Modelling microstructure evolution of weld deposited Ti-6Al-4V2008Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The microstructure and consequently the mechanical properties of titanium alloys are highly dependent on the temperature history endured by the material. The manufacturing process of metal deposition induces repetitive cooling and heating in the material determining a specific microstructure. The presented study is devoted to developing and implementing a microstructure model for Ti-6Al-4V intended to be coupled to a thermo- mechanical model of the metal deposition process.

    Microstructural analysis of the metal deposited samples was first performed to understand the formed microstructure. A set of representative parameters for microstructure modelling were then selected as representative for the known impact of Ti-6Al-4V microstructure on mechanical properties. Evolution equations for these parameters were implemented for thermal finite element analysis of the process. Six representative state variables are modelled: the phase volume fraction of total alpha, beta, Widmanstätten alpha, grain boundary alpha, martensite alpha, and the alpha lath thickness. Heating, cooling and repeated re-heating involved in the process of metal deposition are taken into account in the model. The phase transformations were modelled based on a diffusionnal theory described by a Johnson-Mehl-Avrami formulation, as well as diffusionless transformations for the martensite alpha formation and the beta reformation during reheating. The Arrhenius equation is applied as a simplification to model temperature dependent alpha lath size calculation. Grain growth is not included in the present formulation, but would have to be added for capturing alpha lath coarsening during long term heat treatment.

    The temperature history during robotised tungsten inert gas deposition welding is simulated together with the microstructure. The implementation of the model handles well the complex cyclic thermal loading from the metal deposition process. A particular banded structure observed in the metal deposited microstructure is partially explained using the proposed microstructure model. It is concluded that although qualitatively interesting results have been achieved, further calibration testing over a wider range of temperature histories must be performed to improve the transformation kinetic parameters for reliable quantitative predictions of the microstructure.

  • 23.
    Charles, Corinne
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Järvstråt, Niklas
    University West, Department of Engineering Science, Division of Production Engineering.
    Modelling Ti-6Al-4V microstructure by evolution laws implemented as finite element subroutines:: Application to TIG metal deposition2008In: 8 th International Conference on Trends in welding research,: Pine Mountain, Georgia, June 2-6, 2008Conference paper (Other academic)
  • 24.
    Charles Murgau, Corinne
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Pederson, R.
    Luleå University of Technology, Division of Material Science.
    Lindgren, L. E.
    Luleå University of Technology, Division of Material Mechanics.
    A model for Ti-6Al-4V microstructure evolution for arbitrary temperature changes2012In: Modelling and Simulation in Materials Science and Engineering, ISSN 0965-0393, E-ISSN 1361-651X, Vol. 20, no 5, p. 055006-Article in journal (Refereed)
    Abstract [en]

    This paper presents a microstructure model for the titanium alloy Ti-6Al-4V designed to be used in coupled thermo-metallurgical-mechanical simulations of, e.g., welding processes. The microstructure evolution is increasingly taken into consideration in analyses of manufacturing processes since it directly affects the mechanical properties. Thermally driven phase evolutions are accounted for in the model. A state variable approach is adopted to represent the microstructure with the objective to integrate the microstructure changes with a thermomechanical model of manufacturing process simulation such as welding. The model is calibrated using the literature data and also validated against a cyclic temperature history during multi-pass welding.

  • 25.
    Chen, Y.
    et al.
    University of Manchester, School of Materials, Manchester, United Kingdom.
    Zhao, X.
    Shanghai Jiao Tong University, Shanghai Key Laboratory of Advanced High-Temperature Materials and Precision Forming, Shanghai, China .
    Dang, Y.
    University of Manchester, School of Materials, Manchester, United Kingdom.
    Xiao, Ping
    University of Manchester, School of Materials, Manchester, United Kingdom.
    Curry, Nicholas
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Nylén, Per
    University West, Department of Engineering Science, Division of Production Engineering.
    Characterization and understanding of residual stresses in a NiCoCrAlY bond coat for thermal barrier coating application2015In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 94, p. 1-14Article in journal (Refereed)
    Abstract [en]

    The residual stresses in a NiCoCrAlY bond coat deposited on a Ni-base superalloy substrate after oxidation at 1150 °C were studied by X-ray diffraction using the sin2Ψ technique. The stresses were found to be tensile; they first increased and then decreased with oxidation time. High temperature stress measurement indicated that the stress developed and built up upon cooling, predominantly within the temperature range from 1150 °C to 600 °C. Microstructural examination suggested that, due to the limited penetration depth into the bond coat, the X-ray only probed the stress in a thin surface layer consisting of the single γ-phase formed through Al depletion during oxidation. Quantitative high temperature X-ray diffraction analysis revealed that, above 600 °C, the volume fraction of the β-phase in the bond coat increased with decreasing temperature. The mechanisms of stress generation in the bond coat were examined and are discussed based on the experiments designed to isolate the contribution of possible stress generation factors. It was found that the measured bond coat stresses were mainly induced by the volume change of the bond coat associated with the precipitation of the β-phase upon cooling.

  • 26.
    Choquet, Isabelle
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Degond, Pierre
    Universit´e Paul Sabatier, Mathématiques pour l’Industrie et la Physique.
    Lucquin-Desreux, Brigitte
    Universit´e Pierre et Marie Curie-Paris 6, Laboratoire Jacques-Louis Lions.
    A strong ionization model in plasma physics2009In: Mathematical and Computer Modelling, Vol. 49, no 1-2, p. 88-113Article in journal (Refereed)
  • 27.
    Choquet, Isabelle
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Javidi Shirvan, Alireza
    University West, Department of Engineering Science, Division of Production Engineering.
    Nilsson, Håkan
    Chalmers University of Technology.
    Electric welding arc modeling with the three-dimensional solver OpenFOAM: A comparison of different electromagnetic models2011In: 64 th Annual Assembly and International Conference of International Institute of Welding, 64th IWW: Chennai, 17-22 july, 2011. Working group 212, 2011, p. 212-1189-11-1-212-1189-11-16Conference paper (Other academic)
    Abstract [en]

    This study focuses on the modeling of a plasma arc heat source in the context ofelectric arc welding. The model was implemented in the open source CFD softwareOpenFOAM-1.6.x, coupling thermal fluid mechanics in three dimensions with electromagnetics.Different approaches were considered for modeling the electromagneticfields: i) the three-dimensional approach, ii) the two-dimensional axi-symmetric approach,iii) the electric potential formulation, and iv) the magnetic field formulation asdescribed by Ramírez et al. [1]. The underlying assumptions and the differencesbetween these models are detailed. The models i) to iii) reduce to the same quasione-dimensional limit for an axi-symmetric configuration with negligible radial currentdensity, contrary to the formulation iv). The models ii) to iv) cannot represent the samephysics when the radial current density is significant, such as for a short arc or anelectrode with a conical tip. The models i) to iii) were retained for doing numerical simulations.The corresponding solvers were tested against analytic solution for an infiniteelectric rod. Perfect agreement was obtained for all the models tested. The completesolver (thermal fluid coupled with electromagnetics) was tested against experimentalmeasurements for Gas Tungsten Arc Welding (GTAW). The shielding gas was argon,the arc was short (2mm), the electrode tip conical, and the configuration axi-symmetric.Anode and cathode were treated as boundary conditions. The models i) and ii) lead tothe same results, but not the formulation iii). It indeed neglects the radial current densitycomponent, resulting in a poor estimation of the magnetic field, and in turn of thearc velocity. Limitations of the complete solver were investigated changing also the gascomposition, and testing boundary conditions. These conditions, difficult to measureand to estimate a priori, significantly affect the simulation results.

  • 28.
    Choquet, Isabelle
    et al.
    University West, Department of Engineering Science.
    Javidi Shirvan, Alireza
    University West, Department of Engineering Science, Division of Production Engineering.
    Nilsson, Håkan
    On the choice of electromagnetic model for shorthigh-intensity arcs, applied to welding2012In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 45, no 20, p. 205203-Article in journal (Refereed)
    Abstract [en]

    Four different approaches were considered for modelling the electromagneticfields of high-intensity electric arcs: i) the three-dimensional model, ii) the twodimensionalaxi-symmetric model, iii) the electric potential formulation, and iv) themagnetic field formulation. The underlying assumptions and the differences betweenthese models are described in detail. Models i) to iii) reduce to the same limit for anaxi-symmetric configuration with negligible radial current density, contrary to modeliv). Models i) to iii) were retained and implemented in the open source CFD softwareOpenFOAM. The simulation results were first validated against the analytic solutionof an infinite electric rod. Perfect agreement was obtained for all the models tested.The electromagnetic models i) to iii) were then coupled with thermal fluid mechanicsin OpenFOAM, and applied to the calculation of an axi-symmetric Gas Tungsten ArcWelding (GTAW) test case with short arc (2mm) and truncated conical electrode tip.Models i) and ii) lead to the same simulation results, but not model iii). Model iii)is suited in the specific limit of long axi-symmetric arc, with negligible electrode tipeffect. For short axi-symmetric arc, the more general axi-symmetric formulation ofmodel ii) should instead be used.

  • 29.
    Choquet, Isabelle
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Nilsson, Håkan
    Chalmers University of Technology.
    Javidi Shirvan, Alireza
    University West, Department of Engineering Science, Division of Production Engineering.
    Stenbacka, Nils
    University West, Department of Engineering Science, Division of Production Engineering.
    Numerical simulation of Ar-x%CO2 shielding gas and its effect on an electric welding arc2011In: IIW Commission XII Doc. XII-2017-11, 2011, p. 1-12Conference paper (Other academic)
    Abstract [en]

    This study focuses on the simulation of a plasma arc heat source in the context of electric arc welding. The simulation model was implemented in the open source CFD software OpenFOAM-1.6.x, in three space dimensions, coupling thermal fluid mechanics with electromagnetism. Two approaches were considered for calculating the magnetic field: i) the three-dimensional approach, and ii) the so-called axisymmetric approach. The electromagnetic part of the solver was tested against analytic solution for an infinite electric rod. Perfect agreement was obtained. The complete solver was tested against experimental measurements for Gas Tungsten Arc Welding (GTAW) with an axisymmetric configuration. The shielding gas was argon, and the anode and cathode were treated as boundary conditions. The numerical solutions then depend significantly on the approach used for calculating the magnetic field. The so-called axisymmetric approach indeed neglects the radial current density component, mainly resulting in a poor estimation of the arc velocity. Plasma arc simulations were done for various Ar-x%CO2 shielding gas compositions: pure argon (x=0), pure carbon dioxide (x=100), and mixturesof these two gases with x=1 and 10% in mole. The simulation results clearly show that the presence of carbon dioxide results in thermal arc constriction, and increased maximum arc temperature and velocity. Various boundary conditions were set on the anode and cathode (using argon as shielding gas) to evaluate their influence on the plasma arc. These conditions, difficult to measure and to estimate a priori, significantly affect the heat source simulation results. Solution of the temperature and electromagnetic fields in the anode and cathode will thus be included in the forthcoming developments.

  • 30.
    Choquet, Isabelle
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Nilsson, Håkan
    Chalmers University of Technology.
    Sass-Tisovskaya, Margarita
    University West, Department of Engineering Science, Division of Production Engineering.
    Modeling and simulation of a heat source in electric arc welding2011In: SPS11 : The 4th International Swedish Production Symposiom: Lund, 3-5 maj, 2011, 2011, p. 201-211Conference paper (Refereed)
    Abstract [en]

    This study focused on the modeling and simulation of a plasma heat source applied toelectric arc welding. The heat source was modeled in three space dimensions couplingthermal fluid mechanics with electromagnetism. Two approaches were considered forcalculating the magnetic field: i) three-dimensional, and ii) axi-symmetric. The anodeand cathode were treated as boundary conditions. The model was implemented in theopen source CFD software OpenFOAM-1.6.x. The electromagnetic part of the solverwas tested against analytic solution for an infinite electric rod. Perfect agreement wasobtained. The complete solver was tested against experimental measurements for GasTungsten Arc Welding (GTAW) with an axi-symmetric configuration. The shielding gaswas argon with thermodynamic and transport properties covering a temperature rangefrom 200 to 30 000 K. The numerical solutions then depend greatly on the approachused for calculating the magnetic field. The axi-symmetric approach indeed neglectsthe radial current density component, mainly resulting in a poor estimation of the arcvelocity. Various boundary conditions were set on the anode and cathode. Theseconditions, difficult to measure and to estimate a priori, significantly affect the plasmaheat source simulation results. Solution of the temperature and electromagnetic fieldsin the electrodes will thus be included in the forthcoming developments.

  • 31.
    Choquet, Isabelle
    et al.
    University West, Department of Technology, Mathematics and Computer Science.
    Nylén, Per
    University West, Department of Engineering Science, Division of Production Engineering.
    Wigren, J
    Deposition Rate Increase in APS Processes by Means of Multiple Injection Ports2004In: Thermal Spray 2004: Advances in Technology and Application: Proceedings of the International Thermal Spray Conference 10–12 May 2004, Osaka, Japan, 2004, p. 691-695Conference paper (Other academic)
  • 32.
    Christensen, Tommy
    University West, Department of Engineering Science, Division of Production Engineering.
    Lean Automation på Saab Automobile AB: ett hållbart och flexibelt produktionskoncept2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A new concept of production – Lean Automation – is being developed and implemented at Saab Automobile AB. The aim is to develop solutions for automation that supports the Lean Production principals and way of work.

    A basic idea is that automation should be build from simple, standardized and modular equipment and that it can be reconfigured by in house personnel.

    During 2010, two pilots have been installed: Transport using a simple AGV (Lean AGV) and Lean Automation Robot Cell (LARC). Those components are parts of this study that is aiming for a production system with an unchanged high level of productivity also during periods of frequent changes in volume and product scope.

    The study underlines the importance of gathering the production personnel to enable work balancing, but also to achieve a visual process where errors urgently can be discovered and resolved. The robots work balancing requires a somewhat different approach focusing on the distribution of work elements and taking advantage of the equalizing effect in a common production flow.

    A tool for an expedient balancing of value added work is introduced. The tool is intended for the balancing of both manual and robotized work.

    Further, a method to connect the sub assembly level to the main flow is presented. Fork lift trucks and manually loaded feeders is replaced by a simple flow of AGV’s. The system is conveying information about the state of production through the presence of empty carriers. Through this visual system, plus the use of the team concept to achieve a cheap and efficient buffer, shortage of material is prevented.

    For the selection of internal material flow systems, a set of general guidelines is proposed and exemplified. Finally, the adoption of different solutions for flexibility is linked to the level of assembly and this is also linked to the aspects of parallel versus serial production flow.

  • 33.
    Christiansson, Anna-Karin
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production Engineering.
    Heralic, Almir
    University West, Department of Engineering Science, Division of Production Engineering.
    Ottosson, Mattias
    University West, Department of Engineering Science, Division of Production Engineering.
    Hurtig, Kjell
    University West, Department of Engineering Science, Division of Production Engineering.
    Automation of a robotised metal deposition system using laser melting of wire2008In: 18th International Conference on Flexible Automation and Intelligent Manufacturing (FAIM 2008): Skövde, 30 June-2 July, 2008, p. 122-129Conference paper (Other academic)
    Abstract [en]

    This paper presents a system for full automation of free-form-fabrication of fully dense metal structures using robotized laser melting of wire. The structure is built of beads of melted wire laid side by side and layer upon layer governed by synchronized robot motion. By full automation is here meant that the process starts with a product specification of a component, and ends in a geometrically validated dense metal component fulfilling industrial material requirements. Due to the complexity of this flexible manufacturing system, a number of different disciplines are involved. This paper discusses mainly the system design, which includes how off-line programming is used for automatic generation of code and how feedback control is used for on-line adjustment of parameters based on desired building properties. To meet industrial needs, the project is carried out in a close cooperation between research and development activities in academy and industry.

  • 34.
    Clement, C.
    et al.
    National School of Engineers, University of Limoges, Limoges, 87280, France.
    Sadeghimeresht, Esmaeil
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Lyphout, Christophe
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Nylén, Per
    University West, Department of Engineering Science, Division of Production Engineering.
    Corrosion behavior of HVAF- and HVOF-sprayed high-chromium Fe-based coatings2015Conference paper (Refereed)
    Abstract [en]

    Fe-based coatings with three particular elemental compositions and two different powder particle size were prepared by high-velocity air fuel (HVAF) and high-velocity oxy fuel (HVOF) techniques. The corrosion behavior of which were comparatively studied in 3.5 wt.% NaCl solution. The results indicated that the coatings produced by HVAF process exhibited denser structure with lower porosity. Polarization and electrochemical impedance spectroscopy (EIS) tests indicated that the HVAF coatings provided better corrosion resistance than the HVOF coatings. The presence of defects was significant in HVOF coatings. The investigation illustrated that the corrosion paths initiated and grow through defects of the coating. Furthermore, adding Cr strongly improved the corrosion resistance of the coatings. The results confirmed that the cheap HVAF process could be a potential alternative to HVOF to fabricate Fe-based coatings for industrial applications.

  • 35.
    Curry, Nicholas
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    Janikowski, Wysomir
    University of Manchester.
    Pala, Zdenek
    Academy of Sciences of the Czech Republic, Institute of Plasma Physics.
    Vilémová, Monica
    Academy of Sciences of the Czech Republic, Institute of Plasma Physics.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Production Engineering.
    Impact of Impurity Content on the Sintering Resistance and Phase Stability of Dysprosia- and Yttria-Stabilized Zirconia Thermal Barrier Coatings2014In: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 23, no 1-2, p. 160-169Article in journal (Refereed)
    Abstract [en]

    Dysprosia-stabilized zirconia (DySZ) is a promising candidate to replace yttria-stabilized zirconia (YSZ) as a thermal barrier coating due to its lower inherent thermal conductivity. It is also suggested in studies that DySZ may show greater stability to high temperature phase changes compared to YSZ, possibly allowing for coatings with extended lifetimes. Separately, the impurity content of YSZ powders has been proven to influence high-temperature sintering behavior. By lowering the impurity oxides within the spray powder, a coating more resistant to sintering can be produced. This study presents both high purity and standard purity dysprosia and YSZ coatings and their performance after a long heat treatment. Coatings were produced using powder with the same morphology and grain size; only the dopant and impurity content were varied. Samples have been heat treated for exposure times up to 400 h at a temperature of 1150 °C. Samples were measured for thermal conductivity to plot the evolution of coating thermal properties with respect to exposure time. Thermal conductivity has been compared to microstructure analysis and porosity measurement to track structural changes. Phase analysis utilizing x-ray diffraction was used to determine differences in phase degradation of the coatings after heat treatment. © 2013 ASM International.

  • 36.
    Curry, Nicholas
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    Janikowski, Wyszomir
    University of Mancheste.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Production Engineering.
    Impact of impurity content on the sintering resistance of dysprosia and yttria stabilised zirconia thermal barrier coatings2013In: Proceedings of the International Thermal Spray Conference / [ed] Editor: Rogerio S. Lima, Arvind Agarwal, Margaret M. Hyland, Yuk-Chiu Lau, Georg Mauer, André McDonald, and Filofteia-Laura, ASM International, 2013, p. 557-563Conference paper (Refereed)
    Abstract [en]

    Dysprosia stabilised zirconia (DySZ) is a promising candidate to replace yttria stabilised zirconia (YSZ) as a thermal barrier coating due to its lower inherent thermal conductivity. It is also suggested in studies that DySZ may show greater stability to high temperature phase changes compared to YSZ, possibly allowing for coatings with extended lifetimes. Separately, the impurity content of YSZ powders has been proven to influence high temperature sintering behaviour. By lowering the impurity oxides within the spray powder, a coating more resistant to sintering can be produced. This study presents both high purity and standard purity dysprosia and yttria stabilised zirconia coatings and their performance after a long heat treatment. Coatings were produced using powder with the same morphology and grain size; only the dopant and impurity content were varied. Samples have been heat treated for exposure times up to 400 hours at a temperature of 1150°C. Samples were subsequently measured for thermal conductivity to plot the evolution of coating thermal properties with respect to exposure time. Thermal conductivity has been compared to microstructure analysis and porosity measurement to track structural changes due to sintering.

  • 37.
    Curry, Nicholas
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Markocsan, Nicolaie
    University West, Department of Engineering Science.
    Goddard, Caroline
    Manchester University.
    Influence of Sensor contact on the Thermal Conductivity Values of Thermal Barrier Coatings: Part 1 Experimental2010In: Proceedings of the 24th International Conference on Surface Modification Technologies: 7-9 sept, Dresden, 2010, p. 317-327Conference paper (Refereed)
  • 38.
    Curry, Nicholas
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Production Engineering.
    Li, Xin-Hai
    Tricoire, Aurelien
    Dorfman, Mitchell
    Next Generation Thermal Barrier Coatings for the Gas Turbine Industry2010In: Proceedings of the Thermal Spray: Global Solutions for Future Application (ITSC 2010) Conference: Singapore, May 3-5, 2010, 2010, p. 716-722Conference paper (Refereed)
  • 39.
    Curry, Nicholas
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Production Engineering.
    Li, Xin-Hai
    Siemens Industrial Turbomachinery AB, Finspong, Sweden.
    Tricoire, Aurélien
    Volvo Aero, Trollhättan.
    Dorfman, Mitch
    Sulzer Metco, Westbury, United States.
    Next generation thermal barrier coatings for the gas turbine industry2011In: Journal of Thermal Spray Technology, Vol. 20, no 1-2, p. 108-115Article in journal (Refereed)
    Abstract [en]

    The aim of this study is to develop the next generation of production ready air plasma sprayed thermal barrier coating with a low conductivity and long lifetime. A number of coating architectures were produced using commercially available plasma spray guns. Modifications were made to powder chemistry, including high purity powders, dysprosia stabilized zirconia powders, and powders containing porosity formers. Agglomerated & sintered and homogenized oven spheroidized powder morphologies were used to attain beneficial microstructures. Dual layer coatings were produced using the two powders. Laser flash technique was used to evaluate the thermal conductivity of the coating systems from room temperature to 1200 °C. Tests were performed on as-sprayed samples and samples were heat treated for 100 h at 1150 °C. Thermal conductivity results were correlated to the coating microstructure using image analysis of porosity and cracks. The results show the influence of beneficial porosity on reducing the thermal conductivity of the produced coatings. © 2010 ASM International.

  • 40.
    Curry, Nicholas
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    Tang, Zhaolin
    Northwest Mettech Corp., Vancouver, Canada.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Production Engineering.
    Nylén, Per
    University West, Department of Engineering Science, Division of Production Engineering.
    Influence of Bond Coat Surface Roughness on the Structure of Axial Suspension Plasma Spray Thermal Barrier Coatings - Thermal and Lifetime Performance2015In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 268, no April, p. 15-23Article in journal (Refereed)
  • 41.
    Dalaei, K.
    et al.
    Chalmers University of Technology, Department of Materials and Manufacturing Technology.
    Karlsson, B.
    Chalmers University of Technology, Department of Materials and Manufacturing Technology.
    Svensson, L. E.
    University West, Department of Engineering Science, Division of Production Engineering.
    Stability of shot peening induced residual stresses and their influence on fatigue lifetime2011In: Materials Science and Engineering A, Vol. 528, no 3, p. 1008-1015Article in journal (Refereed)
    Abstract [en]

    Mechanical surface treatment methods such as shot peening may improve the fatigue strength of materials. In this study, the effect of shot peening on strain controlled constant amplitude fatigue loading of a near pearlitic microalloyed steel was investigated. The stress amplitudes throughout the whole lifetime were followed, in addition to detailed recording of stress-strain hysteresis loops, particularly at small cycle numbers. The detailed relaxation of residual stresses and the changes in full width of half maximum (FWHM) of the X-ray peak at the surface and in depth as function of the number of cycles and plastic strain were recorded. By these techniques, the onset as well as the rate of relaxation of residual stresses could be followed at different strain amplitudes. Pronounced increase in lifetime of the shot peened specimens tested at total strain amplitude smaller than 0.3% (corresponding to 0.034% plastic strain amplitude) was achieved. This coincides with reasonably stable residual stresses at the surface and in depth. © 2010 Elsevier B.V.

  • 42.
    De Backer, Jeroen
    et al.
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    Soron, Mikael
    ESAB Welding AB .
    Ilar, Torbjörn
    University West, Department of Engineering Science, Division of Production Engineering.
    Christiansson, Anna-Karin
    University West, Department of Engineering Science, Division of Process and Product Development.
    Friction stir welding with robot for light vehicle design2010In: Proceedings from the 8th International Friction Stir Welding Symposium: Timmendorfer Strand, Germany 18-20 May 2010, The Welding Institute , 2010Conference paper (Other academic)
    Abstract [en]

    Reducing weight is one of the enablers to design more environmentally friendly vehicles. Friction Stir Welding (FSW) supports low weight design through its capability to join different combinations of light weight materials, e.g. different aluminium alloys, but also through its possibilities in producing continuous joints. StiRoLight is a recently started project for robotised FSW for joining of light weight materials emphasising on the vehicle industry, an industry with a long-time experience of robotic welding. The first task involves investigation of force feedback for maintaining the desired contact force. Another important aspect in robotised FSW is the compliance of the robot, which may result in deviations from the pre-programmed path as a result of the high process forces experienced during the welding operation. The further exploration of three-dimensional FSW seams and definition of the process windows will be part of further research within this project.

  • 43.
    De Backer, Jeroen
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Verheyden, Bert
    University West, Department of Engineering Science, Division of Production Engineering.
    Robotic Friction Stir Welding for Automotive and Aviation Applications2010Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Friction Stir Welding (FSW) is a new technology which joins materials by using frictional heat. Inthe first part of this thesis, a profound literature study is performed. The basic principles, therobotic implementation and possibilities to use FSW for high strength titanium alloys areexamined. In the next phase, a FSW-tool is modelled and implemented on an industrial robot in arobot simulation program. Reachability tests are carried out on car body parts and jet engineparts. By using a simulation program with embedded collision detection, all possible weldinglocations are determined on the provided parts. Adaptations like a longer FSW-tool and amodified design are suggested in order to get a better reachability. In different case studies, thenumber of required robots and the reduction of weight and time are investigated and comparedto the current spot welding process.

  • 44.
    Devotta, Ashwin Moris
    et al.
    University West, Department of Engineering Science, Research Enviroment Production Technology West. Sandvik Coromant AB, Sandviken, Sweden.
    Beno, Tomas
    University West, Department of Engineering Science, Division of Production Engineering.
    Löf, Ronnie
    Sandvik Coromant AB, Sandviken, Sweden.
    Espes, Emil
    Sandvik Coromant AB, Stockholm, Sweden.
    Quantitative Characterization of Chip Morphology Using Computed Tomography in Orthogonal Turning Process2015In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 33, p. 299-304Article in journal (Refereed)
    Abstract [en]

    Abstract The simulation of machining process has been an area of active research for over two decades. To fully incorporate finite element (FE) simulations as a state of art tool design aid, there is a need for higher accuracy methodology. An area of improvement is the prediction of chip shape in FE simulations. Characterization of chip shape is therefore a necessity to validate the FE simulations with experimental investigations. The aim of this paper is to present an investigation where computed tomography (CT) is used for the characterization of the chip shape obtained from 2D orthogonal turning experiments. In this work, the CT method has been used for obtaining the full 3D representation of a machined chip. The CT method is highly advantageous for the complex curled chip shapes besides its ability to capture microscopic features on the chip like lamellae structure and surface roughness. This new methodology aids in the validation of several key parameters representing chip shape. The chip morphology’s 3D representation is obtained with the necessary accuracy which provides the ability to use chip curl as a practical validation tool for FE simulation of chip formation in practical machining operations. The study clearly states the ability of the new CT methodology to be used as a tool for the characterization of chip morphology in chip formation studies and industrial applications.

  • 45.
    Edstorp, Marcus
    University West, Department of Engineering Science, Division of Production Engineering.
    An Investigation of Mesh Moving Methods for Simulating the Deformation of Incompressible Fluid Bodies 2009In: COMSOL Conference: 14-16 okt. 2009, Milan, 2009Conference paper (Other academic)
    Abstract [en]

    In this article we apply a finite element method for approximating the geometrical deformation of a two dimensional incompressible fluid body the flow velocity of which is not constrained along its top boundary. As a pressure force is applied on the free boundary, the domain occupied by the fluid deforms. There are several well established methods for treating this type of problem. The purpose of the present work is to investigate the computational efficiency of a number domain-mapping methods, which are akin to many solid mechanical applications involving large deformations, in that they employ a mapping of the initial configuration range onto the current. However, in fluid dynamical applications the deformation of the fluid body may be very large and contain several vortices. When employing domain-mapping methods, the spatial representations of the element domains are attached to the motion, and the Lagrange formulation is therefore inadequate. Instead we wish to find a motion which minimizes the element deformations and the computational complexity of the problem, while satisfying the kinematic constraint along the boundaries.

     

  • 46.
    Edstorp, Marcus
    University West, Department of Engineering Science, Division of Production Engineering.
    Weld Pool Simulations2008Licentiate thesis, monograph (Other academic)
    Abstract [en]

    This investigation is devoted to the study of welding and its effect on the workpiece, focusing on the thermo and fluid dynamical phenomena occuring during a autogenous or nonautogenous arc fusion welding process. Its aim is to simulate the behaviour of the weld pool and analyze the consequence of the solid-liquid phase change, thus obtaining a methodology for predicting the appearance of weld defects related to solidification and cooling. In order to accomplish this, we solve equations governing a number of continuum mechanical and electromagnetical quantities, as well as consider the motion of the freely moving boundary of the weld pool. Since the state of these quantities is strongly influenced by phenomena such as arc and droplet impingement, non-isothermal phase change, surface tension, Marangoni forces and Lorentz forces, much effort is necessarily devoted to the modelling of the corresponding fluxes and sources, as well as to the implementation of computationally efficient techniques for simulating the geometrical deformation of the workpiece, which in our setting is entirely determined by the motion of the weld pool surface.

    Common to all arc fusion welding processes is the employment of a welding arc. Many techniques rely on the arc to clean and shield the workpiece during the process, however in this study we consider it to be its main purpose to cause the local increase of thermal energy that is required for the establishment of the weld pool, and also to exert the mechanical forces that provoke the subsequent fluid flow which enhances heat transfer and facilitates weld penetration. The physics of the welding arc itself is quite intricate, and although the modelling of the arc is not the prime objective of this research project, we conclude that arc forces act on the pool surface, and that the investigation of the arc behaviour is important insofar that it provides input to the pool model and thus enables a more accurate prediction of the quality of the weldment that is created once the pool has solidified

  • 47.
    Edstorp, Marcus
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Charles, Corinne
    University West, Department of Engineering Science, Division of Production Engineering.
    A Finite Element Methodology for Simulating the Influence of Process Parameters on the Phase Transitions in a GTA weld2009In: Proceedings of the 15th International Conference on the Joining of Materials                , 2009Conference paper (Other academic)
  • 48.
    Ericson Öberg, Anna
    et al.
    Material- och Tillverkningsteknik, Chalmers.
    Johansson, Martin
    Holm, Erik
    Hammersberg, Peter
    Material- och Tillverkningsteknik, Chalmers.
    Svensson, Lars-Erik
    University West, Department of Engineering Science, Division of Production Engineering.
    The Influence of Correct Transfer of Weld Information on Production Cost2012In: 5th Swedish Production Symposium 2012, SPS12: 6-8 nov 2012, Linköping / [ed] Mats Björkman, Linköping, 2012, p. 295-302Conference paper (Other academic)
    Abstract [en]

    This study aims at identifying the causes for deviations between actual and theoretical weld weight. Previous performed studies have shown examples of up to 40% extra weld consumables used in some cases. One consequence is of course higher production cost but it can also give increased weight leading to higher fuel consumption and decreased payload. An interesting aspect is that generous margins on specific production measures dilute important feedback of process variation information preventing and prolonging structural root cause analysis.

    The causes for the observed deviations can heritage from several areas, both technical and within the information handling. The investigation shows that single components of the information structure and system, such as unsuitable demands as well as incapable evaluation methods, significantly influences the reliability of the entire manufacturing process. The common factor concerning when problems occur, seems to be the ability of correct information transfer between different functions in the organisation preventing the mismatch to appear in the interface. Suggestions for improving this situation include cross functional agreements as well as new measuring methods.

  • 49.
    Eriksson, Kristina M
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Hanson, R.
    Chalmers University of Technology.
    Performance impact of options for routing and delivery initiation in tugger train delivery systems2008In: Proceedings of SPS08, Swedish Production Symposium, 18th – 20th November 2008, Stockholm, Sweden, 2008Conference paper (Other academic)
  • 50.
    Eriksson, Robert
    et al.
    Siemens AG, Large Gas Turbines, Huttenstr. 12, 10553, Berlin, Germany.
    Gupta, Mohit Kumar
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Broitman, Esteban
    Linköping University. IFM, 58183, Linköping, Sweden.
    Jonnalagadda, Krishna Praveen
    Linköping University, IEI, 58183, Linköping, Sweden.
    Nylén, Per
    University West, Department of Engineering Science, Division of Production Engineering.
    Lin Peng, Ru
    Linköping University, IEI, 58183, Linköping, Sweden.
    Stresses and Cracking During Chromia-Spinel-NiO Cluster Formation in TBC Systems2015In: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 24, no 6, p. 1002-1014Article in journal (Refereed)
    Abstract [en]

    Thermal barrier coatings (TBC) are used in gas turbines to reduce the temperatures in the underlying substrate. There are several mechanisms that may cause the TBC to fail; one of them is cracking in the coating interface due to extensive oxidation. In the present study, the role of so called chromia-spinel-NiO (CSN) clusters in TBC failure was studied. Such clusters have previously been found to be prone to cracking. Finite element modeling was performed on a CSN cluster to find out at which stage of its formation it cracks and what the driving mechanisms of cracking are. The geometry of a cluster was obtained from micrographs and modeled as close as possible. Nanoindentation was performed on the cluster to get the correct Young’s moduli. The volumetric expansion associated with the formation of NiO was also included. It was found that the cracking of the CSN clusters is likely to occur during its last stage of formation as the last Ni-rich core oxidizes. Furthermore, it was shown that the volumetric expansion associated with the oxidation only plays a minor role and that the main reason for cracking is the high coefficient of thermal expansion of NiO. © 2015 ASM International

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