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  • 1.
    Abebe Mengistu, Bemnet
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Internal sensor measurement to reduce the need of coordinate measuring machines2017Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This thesis presents the approach of determining the machining  errors on a five axis CNC machine using sensors already fitted in the machine to extract valuable data up on process called CITE(CNC Integrity Tracing Equipment) system and measuring the machined workpiece geometry using CMM(Coordinate measurement machine). CITE measurement system is the data acquisition hardware and software system developed by University West for collecting position information from encoders of a machine tool. The collected information could then be used to assess the quality and adjustment of a machine tool, CNC programs and the CNC control parameters. The aim of this study is to examine the roundness and concentricity detection capacity of the CITE system by conducting different milling methods and a turning process. In an example cutting of a workpiece, the CITE measurement system was used for recording the machining process. After that, radial error, centre point deviation and circle roundness errors, analysed using MATLAB based on collected CNC tool movement data. CMM measurement used to verify the results obtained from the CITE measurement system. The investigation conducted on the small circles shows that the CITE measurement system have capability of identifying radial errors in different method of millings (slot, up and down). Centre point deviation and roundness errors measured by the CITE system doesn`t show significant differences between milling methods as seen on CMM measurement.

  • 2.
    Abou Nada, Fahed
    et al.
    Lund University, Department of Physics, Division of Combustion Physics, Box 118, Lund, Swede.
    Lantz, Andreas
    Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Larfeldt, Jenny
    Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Markocsan, Nicolaie
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Alden, Marcus
    Lund University, Department of Physics, Division of Combustion Physics, Box 118, Lund, Swede.
    Richter, Mattias
    Lund University, Department of Physics, Division of Combustion Physics, Box 118, Lund, Swede.
    Remote temperature sensing on and beneath atmospheric plasma sprayed thermal barrier coatings using thermographic phosphors2016Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 302, s. 359-367Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Investigations on remote temperature sensing of yttria stabilized zirconia (YSZ) thermal barrier coatings (TBCs) at the surface and at the bond-coat/top-coat interface were carried out. Using Y2O3:Eu thermographic phosphor as an embedded temperature sensing layer, sub-surface temperature probing through 300 mu m of atmospheric plasma sprayed YSZ is demonstrated. The Y2O3:Eu thermographic phosphor displays a temperature sensitivity ranging between 400 degrees C up to a maximum of 900 degrees C when utilizing the luminescence originating from the 611 nm emission band. Dysprosium stabilized zirconia (10 wt.% DySZ), a TBC material, is also investigated and established as a temperature sensor from 400 degrees C up to a temperature of 1000 degrees C using both the intensity decay time and emission intensity ratio methods. In addition, the luminescence of presumed optically inactive YSZ materials was spectroscopically investigated in terms of optical interferences caused by impurities. A validation temperature probing measurement through 300 mu m of YSZ top-coat was successfully performed in a SGT-800 Siemens burner running at six different operating conditions in an atmospheric combustion rig. (C) 2016 Elsevier B.V. All rights reserved.

  • 3.
    Adegoke, Olutayo
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Andersson, Joel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Ojo, Olanrewaju A.
    University of Manitoba, Winnipeg, Canada.
    Brodin, Håkan
    Siemens Industrial Turbomachinery AB, Finspang, Sweden .
    Pederson, Robert
    GKN Aerospace, Redditch, United Kingdom.
    Laser beam powder bed fusion and post processing of alloy 247LC2019Ingår i: MS and T 2019 - Materials Science and Technology, Materials Science and Technology , 2019, s. 27-34Konferensbidrag (Refereegranskat)
    Abstract [en]

    Alloy 247LC is sensitive to cracking during laser beam powder bed fusion (PBF-LB) manufacturing. Post processing is thus required to close cracks and achieve desired properties. In this study, samples of Alloy 247LC were manufactured by PBF-LB and subsequently post processed by hot isostatic pressing (HIP), HIP + solution and ageing heat treatments. The microstructure was characterized. Results showed cracks in the as-built condition. Cracks were not detected after HIP. Bright microconstituents were observed in the region between the cells, mainly, because of the partitioning of Hf and Ta into the intercellular region, where they presumably form carbides. What is assumed to be oxides were prominent in the microstructure. Thermodynamic calculations showed rapid formation of ?’ precipitates in the alloy, due to the high total concentration of Al and Ta and this was linked to the high hardness values in the as-built condition. © 2019 MS&T19®

  • 4.
    Adli, E.
    et al.
    University of Oslo, Oslo, Norway.
    Gjersdal, H.
    University of Oslo, Oslo, Norway.
    Røhne, O.M.
    University of Oslo, Oslo, Norway.
    Dorholt, O.
    University of Oslo, Oslo, Norway.
    Bang, D.M.
    University of Oslo, Oslo, Norway.
    Thomas, D,
    ESS ERIC, Lund, Sweden.
    Shea, T.
    ESS ERIC, Lund, Sweden.
    Andersson, R.
    ESS ERIC, Lund, Sweden.
    Ibison, M.G.
    University of Liverpool and Cockcroft Institute, Daresbury, UK.
    Welsch, C.P
    University of Liverpool and Cockcroft Institute, Daresbury, UK.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    The Ess Target Proton Beam Imaging Systemas In-Kind Contribution2017Ingår i: Proceedings of IPAC2017, Copenhagen, Denmark, 2017, s. 3422-3425Konferensbidrag (Refereegranskat)
  • 5.
    Agic, Adnan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Analysis of entry phase in intermittent machining2018Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Cutting forces and vibrations are essential parameters in the assessment of a cutting process. As the energy consumption in the machining process is directly affected by the magnitude of the cutting forces it is of vital importance to design cutting edges and select process conditions that will maintain high tool performance through reduced energy consumption. The vibrations are often the cause of poor results in terms of accuracy, low reliability due to sudden failures and bad environmental conditions caused by noise. The goal of this work is to find out how the cutting edge and cutting conditions affect the entry conditions of the machining operation. This is done utilizing experimental methods and appropriate theoretical approaches applied to the cutting forces and vibrations. The research was carried out through three main studies beginning with a force build-up analysis of the cutting edge entry into the workpiece in intermittent turning. This was followed by a second study, concentrated on modelling of the entry phase which has been explored through experiments and theory developed in the first study. The third part was focused on the influence of the radial depth of cut upon the entry of cutting edge into the workpiece in a face milling application. The methodology for the identification of unfavourable cutting conditions is also explained herein. Important insights into the force build-up process help addressing the correlation between the cutting geometries and the rise time of the cutting force. The influence of the nose radius for a given cutting tool and workpiece configuration during the initial entry is revealed. The critical angle i.e. the position of the face milling cutter that results in unfavourable entry conditions has been explained emphasizing the importance of the selection of cutting conditions. Finally, the theoretical methods utilized for the evaluation of the role of cutting edge geometry within entry phase dynamics has been explored. This has revealed the trends that are of interest for selection of cutting conditions and cutting edge design.

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  • 6.
    Agic, Adnan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Edge Geometry Effects on Entry Phase by Forces and Vibrations2020Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Intermittent machining is in general strongly related to the large impacts in the entry phase and related vibrations. The influence of the impact forces and vibrations on the cutting process is dependent on workpiece material, structural properties of the tool-workpiece system, cutting edge geometries and cutting parameters. Cutting forces adopt generally a periodic behaviour that gives rise to forced vibrations. In addition, self-induced vibrations may arise because of lowrigidity and insufficient damping in the tool-workpiece system at specific cutting parameters. The ability of the cutting tool to carry the loads during the entry phase and minimize the vibrations is often the key parameter for an effective machining operation.This research work is based on the experiments, analytical studies and modelling. It was carried out through six main studies beginning with a force build-up analysis of the cutting edge entry into the workpiece in intermittent turning. This was followed by a second study, concentrated on modelling of the entry phase which has partly been explored through experiments and theory developed in the first study.

    The third part was focused on the influence of the radial depth of cut upon the entry of the cutting edge into the workpiece in a face milling application. The methodology for the identification of unfavourable radial depth of cut is also addressed herein. Next, effects of the cutting edge on the vibrations in an end milling application were investigated. This study was related to a contouring operation with the maximum chip thickness in the entry phase when machining steel, ISO P material.

    The results of this work provide some general recommendations when milling this type of workpiece material. After that, the focus was set on the dynamic cutting forces in milling. The force developments over a tooth engagement in milling showed to be strongly dependent on the cutting edge geometry. A significant difference between highly positive versus highly negative geometry was found.

    The implication of this phenomena on the stress state in the cutting edge and some practical issues were analysed. Finally, the role of the helix angle on the dynamic response of a workpiece was investigated. The modelling technique using force simulation and computation of the dynamic response by means of modal analysis was presented. Extensive experimental work was conducted to compare the modelling and experimentally obtained results. The modelling results showed a similar trend as the experimental results. The influence of helix angle on the cutting forces and the dynamic response was explained in detail.The research conducted in this work contributes to the deeper understanding of the influence of the cutting edge geometry and the cutting parameters on the force build up process during the entry phase. The presented studies investigate the force magnitudes, force rates and dynamic behaviour of the tools and workpieces when machining at the challenging entry conditions. The methodologies applied are focused on the physical quantities as forces and vibrations rather than the experimental studies that evaluate tool life. The methods and results of the research work are of great interest for the design of the cutting tools and optimization of the cutting processes.

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  • 7.
    Agic, Adnan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Seco Tools, Fagersta, Sweden.
    Eynian, Mahdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Hägglund, S.
    Seco Tools, Fagersta, Sweden.
    Ståhl, Jan-Eric
    Lund University, Production and Materials Engineering, Lund, Sweden.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Influence of radial depth of cut on dynamics of face milling application2016Ingår i: The 7th International Swedish Production Symposium, SPS16, Conference Proceedings: 25th – 27th of October 2016, Lund: Swedish Production Academy , 2016, s. 1-9Konferensbidrag (Refereegranskat)
    Abstract [en]

    The choice of milling cutter geometry and appropriate cutting data for certain milling application is of vital importance for successful machining results. Unfavourable selection of cutting conditions might give rise to high load impacts that cause severe cutting edge damage. The radial depth of cut in combination with milling cutter geometry might under some circumstances give unfavourable entry conditions in terms of cutting forces and vibration amplitudes. This phenomenon originates from the geometrical features that affect the rise time of the cutting edge engagement into work piece at different radial depths of cut. As the radial depth of cut is often an important parameter, particularly when machining difficult to cut materials, it is important to explore the driving mechanism behind vibrations generation. In this study, acceleration of the work piece is measured for different radial depths of cut and cutting edge geometries. The influence of the radial depth of cut on the dynamical behaviour is evaluated in time and frequency domains. The results for different radial depths of cut and cutting geometries are quantified using root mean square value of acceleration. The outcome of this research study can be used both for the better cutting data recommendations and improved tool design.

  • 8.
    Agic, Adnan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Eynian, Mahdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Hägglund, S.
    Seco Tools, Fagersta, Sweden.
    Ståhl, J-E
    Lund University ,Production and Materials Engineering, Lund Sweden.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Influence of radial depth of cut on entry conditions and dynamics in face milling application2017Ingår i: Journal of Superhard Materials, ISSN 1063-4576, Vol. 39, nr 4, s. 259-270Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The choice of milling cutter geometry and appropriate cutting data for certain milling application is of vital importance for successful machining results. Unfavorable selection of cutting conditions might give rise to high load impacts that cause severe cutting edge damage. Under some circumstances the radial depth of cut in combination with milling cutter geometry might give unfavorable entry conditions in terms of cutting forces and vibration amplitudes. This phenomenon is originated from the geometrical features that affect the rise time of the cutting edge engagement into workpiece at different radial depths of cut. As the radial depth of cut is often an important parameter, particularly when machining difficult-to-cut materials, it is important to explore the driving mechanism behind vibrations generation. In this study, acceleration of the workpiece is measured for different radial depths of cut and cutting edge geometries. The influence of the radial depth of cut on the dynamical behavior is evaluated in time and frequency domains. The results for different radial depths of cut and cutting geometries are quantified using the root mean square value of acceleration. The outcome of this research study can be used both for the better cutting data recommendations and improved tool design.

  • 9.
    Agic, Adnan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Seco Tools, Fagersta, Sweden.
    Eynian, Mahdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Ståhl, J. -E
    Lund University, Production and Materials Engineering, Lund, Sweden.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Experimental analysis of cutting edge effects on vibrations in end milling2019Ingår i: CIRP - Journal of Manufacturing Science and Technology, ISSN 1755-5817, E-ISSN 1878-0016, Vol. 24, s. 66-74Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The ability to minimize vibrations in milling by the selection of cutting edge geometry and appropriate cutting conditions is an important asset in the optimization of the cutting process. This paper presents a measurement method and a signal processing technique to characterize and quantify the magnitude of the vibrations in an end milling application. Developed methods are then used to investigate the effects of various cutting edge geometries on vibrations in end milling. The experiments are carried out with five cutting edge geometries that are frequently used in machining industry for a wide range of milling applications. The results show that a modest protection chamfer combined with a relatively high rake angle has, for the most of cutting conditions, a reducing effect on vibration magnitudes. Furthermore, dynamics of a highly positive versus a highly negative cutting geometry is explored in time domain and its dependency on cutting conditions is presented. The results give concrete indications about the most optimal cutting edge geometry and cutting conditions in terms of dynamic behavior of the tool.

  • 10.
    Agic, Adnan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Seco Tools, Fagersta, Sweden.
    Eynian, Mahdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Ståhl, Jan Erik
    Lund University, Production and Materials Engineering, Lund, Sweden.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Dynamic effects on cutting forces with highly positive versus highly negative cutting edge geometries2019Ingår i: International Journal on Interactive Design and Manufacturing, ISSN 1955-2513, E-ISSN 1955-2505, Vol. 13, nr 2, s. 557-565Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Understanding the influence of the cutting edge geometry on the development of cutting forces during the milling process is of high importance in order to predict the mechanical loads on the cutting edge as well as the dynamic behavior on the milling tool. The work conducted in this study involves the force development over the entire engagement of a flute in milling, from peak force during the entry phase until the exit phase. The results show a significant difference in the behavior of the cutting process for a highly positive versus a highly negative cutting edge geometry. The negative edge geometry gives rise to larger force magnitudes and very similar developments of the tangential and radial cutting force. The positive cutting edge geometry produces considerably different developments of the tangential and radial cutting force. In case of positive cutting edge geometry, the radial cutting force increases while the uncut chip thickness decreases directly after the entry phase; reaching the peak value after a certain delay. The radial force fluctuation is significantly higher for the positive cutting edge geometry. The understanding of such behavior is important for modelling of the milling process, the design of the cutting edge and the interactive design of digital applications for the selection of the cutting parameters.

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  • 11.
    Agic, Adnan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Seco Tools AB,Fagersta, Sweden.
    Gutnichenko, Oleksandr
    Division of Production and Materials Engineering, Lund University, Sweden.
    Eynian, Mahdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Ståhl, Jan-Eric
    Division of Production and Materials Engineering, Lund University, Sweden.
    Influence of cutting edge geometry on force build-up process in intermittent turning2016Ingår i: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 46, s. 364-367Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the intermittent turning and milling processes, during the entry phase the cutting edges are subjected to high impact loads that can give rise to dynamical and strength issues which in general cause tool life reduction. In this study the effect of geometrical features of the cutting tool on the force generation during the entry phase is investigated. Cutting forces are measured by a stiff dynamometer at a high sampling frequency. In addition, the chip load area is analyzed and related to the measured cutting force. The results show that micro-geometrical features, in particular the protection chamfer, significantly affect the force generation during the entry phase.

  • 12.
    Alehojat, Seyedmobin
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Effect of HVAF sprayed NiCoCrAlY coating on oxidation performance of E B PBF manufactured Alloy 7182019Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    There is an upsurge of research interest on Alloy 718 additively manufactured (AM) by electron beam powder bed fusion (EB-PBF) technique in aero and land-based gas turbine engines. However, the surface quality hence the oxidation performance of the manufactured components is of great concern. Along with surface roughness resulted from partially melted powder particles, surface defects such as balls, satellites, microcracks as well as up-skin and down-skin surfaces can enhance the vulnerability of the manufactured parts to oxidation. When the surface is unable to withstand the exposed environment adequately, oxidation can be triggered. The surface-induced failures are increasingly becoming more challenging as the AM components often have complex geometries that render them even more difficult to finish. So, the relatively poor surface finish is the barrier to the full exploitation of the AM industry.

    In the present study, a NiCoCrAlY coating deposited by high velocity air-fuel (HVAF) technique on EB-PBF manufactured Alloy 718 was investigated. The oxidation behavior of the parts was investigated in an ambient air environment at 650 and 800 °C for 168 h. The oxidation behavior of the coated samples was analyzed by scanning electron microscopy (SEM) equipped with energy disperse spectroscopy (EDS). The oxidation behavior of the parts was significantly improved after deposition of the thermal spray coating. The oxide scale formed on the surface of the EB-PBF Alloy 718 without the coating was rich in Cr and the oxide scale formed on the surface of the EB-PBF Alloy 718 with NiCoCrAlY coating was rich in Al.

  • 13.
    Algenaid, Wael
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Erosion behaviour of suspension plasma sprayed thermal barrier coatings2018Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Thermal barrier coatings (TBCs) are applied on the surface of hot parts of gas turbine engines to increase the turbine efficiency by providing thermal insulation and also to protect the engine parts from the harsh environment. To maximize these benefits, the TBC must remain intact to the underlying metallic gas turbine components through the life of the gas turbine engines. Typical degradation of TBCs can be attributed to bond coat oxidation, thermal stress etc. In addition to this, erosion can also lead to partial or complete removal of the TBCs especially when the engine operates under erosive environment such as flying over desert area, near active volcanic or offshore ocean environment. Therefore, erosion is also acknowl-edged as a significant life-limiting factor for TBCs. Suspension plasma spray (SPS) is a rela-tively new technique capable of producing coatings with lamellar/vertically cracked and co-lumnar microstructures. Moreover, SPS is a cheaper process compared with Electron Beam Physical Vapor Deposition (EB-PVD) which is a well-known commercial technique to produce columnar TBCs. This work aims to study the effect of microstructure produced by SPS on the erosion performance of TBCs. Six different suspensions of 8 wt. % Yttria Stabilized Zirconia (YSZ) ceramic powder with distinct suspension characteristics such as solid load, solvent type and particle size distribution were used to spray six different TBCs using an identical bond coat and substrate. The as-sprayed TBCs were subjected to an air jet erosion test at room temperature, and their erosion resistance was compared. It was found that the total porosity content in the coating was the most predominant factor influencing the erosion performance of the coatings. Moreover, vertically cracked coatings resulted in low total po-rosity which in turn lead to high erosion resistance. This result was also supported by one of the columnar coatings which had the lowest porosity and highest erosion resistance as com-pared to other columnar coatings. Therefore, it is recommended to produce a columnar coating with lower porosity content for SPS TBCs.

  • 14.
    Algenaid, Wael
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Ganvir, Ashish
    GKN Aerospace Engine Systems, Trollhättan, Sweden.
    Calinas, Rosa Filomena
    Innovnano materials, Coimbra, Portugal.
    Varghese, Johny
    University of Hyderabad, Hyderabad, India.
    Rajulapati, Koteswararao V.
    University of Hyderabad, Hyderabad, India.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Influence of microstructure on the erosion behaviour of suspension plasma sprayed thermal barrier coatings2019Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 375, s. 86-99Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thermal barrier coatings (TBCs) are applied on the surface of hot parts of gas turbine engines to increase the turbine efficiency by providing thermal insulation and to protect the engine parts from the harsh environment. Typical degradation of TBCs can be attributed to bond coat oxidation, thermal stress etc. In addition to this, erosion can also lead to partial or complete removal of the TBCs especially when the engine operates under erosive environment such as flying over desert area, near active volcanic or offshore ocean environment. Suspension Plasma Spraying (SPS) is a promising technique for TBC applications by virtue of its ability to produce a strain-tolerant porous-columnar microstructure that combines the benefits of both electron beam physical vapor deposited (EB-PVD) as well as atmospheric plasma sprayed (APS) coatings. This work investigates the influence of various coating microstructures produced by SPS on their erosion behavior. Six different coatings with varied microstructures produced using different suspensions with distinct characteristics were studied and their erosion resistance was compared. Results showed significant influence of SPS TBCs microstructures on the erosion resistance. Furthermore, the erosion resistance of SPS TBCs showed a close correlation between fracture toughness and the erosion rate, higher fracture toughness favours superior erosion resistance. © 2019 Elsevier B.V.

  • 15.
    Anderberg, Staffan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Pejryd, Lars
    3Production Technology Centre, Innovatum AB.
    A survey of metal working companies’ readiness for process planning performance measurements2009Ingår i: IEEE International Conference on Industrial Engineering and Engineering Management, IEEM 8-11 sep, 2009, Hong-Kong, 2009, s. 1910-1914Konferensbidrag (Refereegranskat)
    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.

  • 16.
    Anderberg, Staffan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Pejryd, Lars
    Production Technology Centre, Innovatum AB.
    CNC machining process planning productivity – a qualitative survey2009Ingår i: Proceedings of The International 3'rd Swedish Production Symposium, SPS 09, 2009, s. 228-235Konferensbidrag (Refereegranskat)
    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.

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    Anderberg_Beno_Pejryd_CNC machining process planning productivity - a qualitative survey
  • 17.
    Anderberg, Staffan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Pejryd, Lars
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Energy and Cost Efficiency in CNC Machining from a Process Planning Perspective2011Ingår i: 9th Global Conference on Sustainable Manufacturing: Sustainable Manufacturing –Shaping Global Value Creation / [ed] Günther Seliger, 2011, s. 383-389Konferensbidrag (Refereegranskat)
    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.

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    Anderberg Beno Pejryd - Energy and cost efficiency in CNC machining from a process planning perspective
  • 18.
    Anderberg, Staffan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Pejryd, Lars
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Process planning for cnc machining of swedish subcontractors: A web survey2014Ingår i: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 17, s. 732-737Artikel i tidskrift (Refereegranskat)
    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.

  • 19.
    Anderberg, Staffan
    et al.
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap, Avd för maskinteknik.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Pejryd, Lars
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Production preparation methodology in Swedish metal working industry - a State of the Art investigation2008Ingår i: 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, s. 443-450Konferensbidrag (Övrigt vetenskapligt)
    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%.

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    Anderberg_Beno_Pejryd - Preparation Methodology in Swedish metal working industry
  • 20.
    Anderberg, Staffan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Kara, Sami
    University of New South Wales.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Impact of energy efficiency on computernumerically controlled machining2010Ingår i: Proceedings of the Institution of mechanical engineers. Part B, journal of engineering manufacture, ISSN 0954-4054, E-ISSN 2041-2975, Vol. 224, nr B4, s. 531-541Artikel i tidskrift (Refereegranskat)
    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.

  • 21.
    Aranke, Omkar
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Effect of spray parameters on micro-structure and lifetime of suspension plasma sprayed thermal barrier coat-ings2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Fabrication of Thermal Barrier Coatings (TBCs) with higher lifetime and relatively cheaper processes is of particular interest for gas turbine applications. Suspension Plasma Spray (SPS) is capable of producing coatings with porous columnar structure, and it is also a much cheaper process compared to the conventionally used Electron Beam Physical Vapour Dep-osition (EB-PVD). Although TBCs fabricated using SPS have lower thermal conductivity as compared to other commonly used processes, they are still not commercialized due to their poor lifetime expectancy.

    Lifetime of TBCs is highly influenced by the top coat microstructure. The objective of this work was to study and evaluate the top coat microstructure produced using axial SPS with different process parameters. 8 wt. % Yttria Stabilized Zirconia (YSZ) suspension with 25 % solid load in ethanol was used to spray the top coat. The bond coat was deposited on Has-telloy-X substrates using a NiCoCrAlY powder by High Velocity Air Fuel (HVAF) spray with same process parameters. Influence of the microstructure on lifetime of the coatings was of particular interest in this work. The coating microstructure was analysed using Scanning Electron Microscope (SEM) and it was observed that axial SPS is capable of producing TBCs with varied top coat microstructure from highly porous to densely packed columnar microstructure. The lifetime of the coatings was determined by Thermal Cyclic Fatigue (TCF) testing and Burner Rig Testing (BRT). Porosity and Thermal conductivity of the coat-ings was determined by Image Analysis and Laser Flash Analysis (LFA) respectively.

    From the results obtained, it can be concluded that axial SPS could be a promising method of producing TBCs with low thermal conductivity & high lifetime for high temperature gas turbine applications.

  • 22.
    Aranke, Omkar
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Algenaid, Wael
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Awe, Samuel
    R and D Department, Automotive Components Floby AB, Floby, 52151, Sweden.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Coatings for automotive gray cast iron brake discs: A review2019Ingår i: Coatings, ISSN 2079-6412, Vol. 9, nr 9, artikel-id 552Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Gray cast iron (GCI) is a popular automotive brake disc material by virtue of its high melting point as well as excellent heat storage and damping capability. GCI is also attractive because of its good castability and machinability, combined with its cost-effectiveness. Although several lightweight alloys have been explored as alternatives in an attempt to achieve weight reduction, their widespread use has been limited by low melting point and high inherent costs. Therefore, GCI is still the preferred material for brake discs due to its robust performance. However, poor corrosion resistance and excessive wear of brake disc material during service continue to be areas of concern, with the latter leading to brake emissions in the form of dust and particulate matter that have adverse effects on human health. With the exhaust emission norms becoming increasingly stringent, it is important to address the problem of brake disc wear without compromising the braking performance of the material. Surface treatment of GCI brake discs in the form of a suitable coating represents a promising solution to this problem. This paper reviews the different coating technologies and materials that have been traditionally used and examines the prospects of some emergent thermal spray technologies, along with the industrial implications of adopting them for brake disc applications. © 2019 by the authors.

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  • 23.
    Aranke, Omkar
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Gupta, Mohit Kumar
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Markocsan, Nicolaie
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Li, Xin-Hai
    Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Kjellman, Björn
    GKN Aerospace Sweden AB, Trollhättan, Sweden.
    Microstructural Evolution and Sintering of Suspension Plasma-Sprayed Columnar Thermal Barrier Coatings2019Ingår i: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 28, nr 1-2, s. 198-211Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Suspension plasma spray (SPS) is capable of producing coatings with porous columnar structure, and it is also a much cheaper process compared to the conventionally used electron beam physical vapor deposition (EB-PVD). Although TBCs with a columnar microstructure that are fabricated using SPS have typically lower thermal conductivity than EB-PVD, they are used sparingly in the aerospace industry due to their lower fracture toughness and limited lifetime expectancy. Lifetime of TBCs is highly influenced by the topcoat microstructure. The objective of this work was to study the TBCs produced using axial SPS with different process parameters. Influence of the microstructure on lifetime of the coatings was of particular interest, and it was determined by thermal cyclic fatigue testing. The effect of sintering on microstructure of the coatings exposed to high temperatures was also investigated. Porosity measurements were taken using image analysis technique, and thermal conductivity of the coatings was determined by laser flash analysis. The results show that axial SPS is a promising method of producing TBCs having various microstructures with good lifetime. Changes in microstructure of topcoat due to sintering were seen evidently in porous coatings, whereas dense topcoats showed good resistance against sintering.

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  • 24.
    Augustsson, Svante
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automationssystem.
    Olsson, Jonas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Gustavsson Christiernin, Linn
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser.
    Bolmsjö, Gunnar
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automation och datateknik.
    How to Transfer Information Between Collaborating Human Operators and Industrial Robots in an Assembly2014Ingår i: Proceedings the NordiCHI 2014: The 8th Nordic Conference on Human-Computer Interaction: Fun, Fast, Foundational, ACM Publications, 2014, s. 286-294Konferensbidrag (Refereegranskat)
    Abstract [en]

    Flexible human-robot industrial coproduction will be important in many small and middle-sized companies in the future. One of the major challenges in a flexible robot cell is how to transfer information between the human and the robot with help of existing and safety approved equipment. In this paper a case study will be presented where the first half focus on data transfer to the robot communicating the human's position and movements forcing the robot to respond to the triggers. The second half focuses on how to visualize information about the settings and assembly order to the human. The outcome was successful and flexible, efficient coproduction could be achieved but also a number of new challenges were found.

  • 25.
    Awasthi, Shikha
    et al.
    Material Science and Engineering, Indian Institute of Technology, Kanpur, Kanpur, India .
    Goel, Sneha
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Pandey, Chandra Prabha
    Babu Banarasi Das University, Department of Chemistry, Lucknow, India.
    Balani, Kantesh
    Material Science and Engineering, Indian Institute of Technology, Kanpur, Kanpur, India .
    Multi-Length Scale Tribology of Electrophoretically Deposited Nickel-Diamond Coatings2017Ingår i: JOM: The Member Journal of TMS, ISSN 1047-4838, E-ISSN 1543-1851, Vol. 69, nr 2, s. 227-235Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electrophoretically deposited (EPD) nickel and its composite coatings are widely used to enhance the life span of continuous ingot casting molds in the steel, aerospace and automotive industries. This article reports the effect of different concentrations of diamond particles (2.5–10 g/L) on the wear mechanism of EPD Ni. The distribution of diamond particles in the Ni matrix was observed using Voronoi tessellation. Variation in COF was observed by a fretting wear test to be 0.51 ± 0.07 for Ni, which decreases to 0.35 ± 0.03 for the Ni-diamond coatings. The wear volume of the coatings with 7.5 g/L concentration of diamond was observed to be a minimum (0.051 ± 0.02 × 10−3 mm3) compared with other composite coatings. Further, the micro-scratch testing of the coatings also exhibited a reduced COF (0.03–0.12) for 7.5 g/L diamond concentration compared with Ni (0.08–0.13). Higher wear resistance of the diamond-added coatings (optimum 7.5 g/L concentration) is due to the balance between the dispersion strengthening mechanism and the enhancement of the load-bearing capacity due to the incorporation of diamond particles. Thus, these composites can be used for applications in automotive and aerospace industries. © 2016 The Minerals, Metals & Materials Society

  • 26.
    Badgujar, Amol C.
    et al.
    Centre for Solar Energy Materials, ARCI, Hyderabad, India.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Dhage, Sanjay R.
    Mechanical and Aerospace Engineering Department, University of California, Los Angeles, USA .
    Process Parameter Impact on Selective Laser Ablation of Bilayer Molybdenum Thin Films for CIGS Solar Cell Applications2018Ingår i: Materials focus, ISSN 2169-429X, nr 4, s. 556-562Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cu(In,Ga)Se2 or CIGS absorber layers are a promising candidate for thin film solar cells, with efficiency exceeding 22% having already been demonstrated at the cell level and their commercialization been ramped up. Scribing by selective ablation to achieve monolithic integration is an essential step in CIGS module making to divide a large area cell into a series of inter-connected smaller cells. P1 scribing or electrical isolation of back contact is an essential part of the monolithic integration. Laser-induced scribing of Molybdenum (Mo) back contact of a CIGS solar cell is highly sensitive to process parameters like laser power, pulse duration, and pulse repetition frequency. The above parameters control the scribe width, heat affected zone and process residue directly or indirectly, thereby affecting electrical isolation and module performance. Influence of laser process parameters on scribing of a bilayer Mo thin film back contact has been investigated and is being reported. The scribes obtained employing various laser conditions were characterized for electrical isolation and analyzed by optical microscopy followed by profilometry. High-quality scribing, with a scribe width of 53 μm over a length of 300 mm, was achieved on a bilayer Mo thin film sputtered on a Soda lime glass substrate.

  • 27.
    Balachandramurthi, Arun Ramanathan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Fatigue Properties of Additively Manufactured Alloy 7182018Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Additive Manufacturing (AM), commonly known as 3D Printing, is a disruptive modern manufacturing process, in which parts are manufactured in a layer-wise fashion. Among the metal AM processes, Powder Bed Fusion (PBF) technology has opened up a design space that was not formerly accessible with conventional manufacturing processes. It is, now, possible to manufacture complex geometries, such as topology-optimized structures, lattice structures and intricate internal channels, with relative ease. PBF is comprised of Electron Beam Melting (EBM) and Selective Laser Melting (SLM) processes.

    Though AM processes offer several advantages, the suitability of these processes to replace conventional manufacturing processes must be studied in detail; for instance, the capability to produce components of consistent quality. Therefore, understanding the relationship between the AM process together with the post treatment used and the resulting microstructure and its influence on the mechanical properties is crucial, to enable manufacturing of high-performance components. In this regard, for AM built Alloy 718, only a limited amount of work has been performed compared to conventional processes such as casting and forging. The aim of this work, therefore, is to understand how the fatigue properties of EBM and SLM built Alloy 718, subjected to different thermal post-treatments, is affected by the microstructure. In addition, the effect of as-built surface roughness is also studied.

    Defects can have a detrimental effect on fatigue life. Numerous factors such as the defect type, size, shape, location, distribution and nature determine the effect of defects on properties. Hot Isostatic Pressing (HIP) improves fatigue life as it leads to closure of most defects. Presence of oxides in the defects, however, hinders complete closure by HIP. Machining the as-built surface improves fatiguelife; however, for EBM manufactured material, the extent of improvement is dependent on the amount of material removed. The as-built surface roughness, which has numerous crack initiation sites, leads to lower scatter in fatigue life. In both SLM and EBM manufactured material, fatigue crack propagation is transgranular. Crack propagation is affected by grain size and texture of the material.

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  • 28.
    Balachandramurthi, Arun Ramanathan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Moverare, Johan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Linköping University, Department of Management and Engineering, Linköping, Sweden.
    Dixit, Nikhil
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Deng, Dunyong
    Linköping University, Department of Management and Engineering, Linköping, Sweden.
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Microstructural influence on fatigue crack propagation during high cycle fatigue testing of additively manufactured Alloy 7182019Ingår i: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 149, s. 82-94Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A study of the microstructure of additively manufactured Alloy 718 was performed in order to better understand the parameters that have an influence on the fatigue properties of the material. The specimens were manufactured using two powder bed fusion techniques – Electron Beam Melting (EBM) and Selective Laser Melting (SLM). Four point bending fatigue tests were performed at room temperature with a stress ratio of R = 0.1 and 20 Hz frequency, on material that was either in hot isostatically pressed (HIP) and solution treated and aged (STA) condition or in STA condition without a prior HIP treatment. The grains in the SLM material in the HIP + STA condition have grown considerably both in the hatch and the contour regions; EBM material, in contrast, shows grain growth only in the contour region. Fractographic analysis of the specimens in HIP + STA condition showed a faceted appearance while the specimens in STA condition showed a more planar crack appearance. The crack propagation occurred in a transgranular mode and it was found that precipitatessuch as NbC, TiN or δ-phase, when present, did not affect the crack path. The areas with larger grains corresponded to the faceted appearance of the fracture surface. This could be attributed to the plastic zone ahead of the crack tip being confined within one grain, in case of the larger grains, which promotes single shear crack growth mode

  • 29.
    Balachandramurthi, Arun Ramanathan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Moverare, Johan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Linköping University, Department of Management and Engineering, Linköping, Sweden.
    Dixit, Nikhil
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Influence of defects and as-built surface roughness on fatigue properties of additively manufactured Alloy 7182018Ingår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 735, s. 463-474Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electron beam melting (EBM) and Selective Laser Melting (SLM) are powder bed based additive manufacturing (AM) processes. These, relatively new, processes offer advantages such as near net shaping, manufacturing complex geometries with a design space that was previously not accessible with conventional manufacturing processes, part consolidation to reduce number of assemblies, shorter time to market etc. The aerospace and gas turbine industries have shown interest in the EBM and the SLM processes to enable topology-optimized designs, parts with lattice structures and part consolidation. However, to realize such advantages, factors affecting the mechanical properties must be well understood – especially the fatigue properties. In the context of fatigue performance, apart from the effect of different phases in the material, the effect of defects in terms of both the amount and distribution and the effect of “rough” as-built surface must be studied in detail. Fatigue properties of Alloy 718, a Ni-Fe based superalloy widely used in the aerospace engines is investigated in this study. Four point bending fatigue tests have been performed at 20 Hz in room temperature at different stress ranges to compare the performance of the EBM and the SLM material to the wrought material. The experiment aims to assess the differences in fatigue properties between the two powder bed AM processes as well as assess the effect of two post-treatment methods namely – machining and hot isostatic pressing (HIP). Fractography and metallography have been performed to explain the observed properties. Both HIPing and machining improve the fatigue performance; however, a large scatter is observed for machined specimens. Fatigue properties of SLM material approach that of wrought material while in EBM material defects severely affect the fatigue life. © 2018 Elsevier B.V.

  • 30.
    Balachandramurthi, Arun Ramanathan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Olsson, Jonas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Ålgårdh, Joakim
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Powder Materials & Additive Manufacturing, Swerim AB, SE-164 40, Kista, Sweden.
    Snis, Anders
    Arcam EBM, SE-431 37, Mölndal, Sweden.
    Moverare, Johan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Linköping University, Department of Management and Engineering,SE-581 83, Sweden.
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Microstructure tailoring in Electron Beam Powder Bed Fusion Additive Manufacturing and its potential consequences2019Ingår i: Results in Materials, ISSN 2590-048X, Vol. 1Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electron Beam Powder Bed Fusion process for Alloy 718 was investigated, in the sense of microstructural evolution with varying process conditions. The existence of a geometric relationship between the melt front and the processing parameters was observed. By understanding and capitalizing on this relationship, it was possible to obtain columnar, equiaxed or bimodal microstructure.

  • 31.
    Balachandramurthi Ramanathan, Arun
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Moverare, Johan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Linköping University, Department of Management and Engineering, SE 581 83 Linköping, Sweden.
    Mahade, Satyapal
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Additive Manufacturing of Alloy 718 via Electron Beam Melting: Effect of Post-Treatment on the Microstructure and the Mechanical Properties.2018Ingår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, nr 1, artikel-id E68Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Alloy 718 finds application in gas turbine engine components, such as turbine disks, compressor blades and so forth, due to its excellent mechanical and corrosion properties at elevated temperatures. Electron beam melting (EBM) is a recent addition to the list of additive manufacturing processes and has shown the capability to produce components with unique microstructural features. In this work, Alloy 718 specimens were manufactured using the EBM process with a single batch of virgin plasma atomized powder. One set of as-built specimens was subjected to solution treatment and ageing (STA); another set of as-built specimens was subjected to hot isostatic pressing (HIP), followed by STA (and referred to as HIP+STA). Microstructural analysis of as-built specimens, STA specimens and HIP+STA specimens was carried out using optical microscopy and scanning electron microscopy. Typical columnar microstructure, which is a characteristic of the EBM manufactured alloy, was observed. Hardness evaluation of the as-built, STA and HIP+STA specimens showed that the post-treatments led to an increase in hardness in the range of ~50 HV1. Tensile properties of the three material conditions (as-built, STA and HIP+STA) were evaluated. Post-treatments lead to an increase in the yield strength (YS) and the ultimate tensile strength (UTS). HIP+STA led to improved elongation compared to STA due to the closure of defects but YS and UTS were comparable for the two post-treatment conditions. Fractographic analysis of the tensile tested specimens showed that the closure of shrinkage porosity and the partial healing of lack of fusion (LoF) defects were responsible for improved properties. Fatigue properties were evaluated in both STA and HIP+STA conditions. In addition, three surface conditions were also investigated, namely the 'raw' as-built surface, the machined surface with the contour region and the machined surface without the contour region. Machining off the contour region completely together with HIP+STA led to significant improvement in fatigue performance.

  • 32.
    Beno, Tomas
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Anderberg, Staffan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för process- och produktutveckling.
    Green machining: improving the bottom line2009Konferensbidrag (Övrigt vetenskapligt)
    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.

  • 33.
    Beno, Tomas
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Hulling, U
    Volvo Aero Corporation, Trollhättan.
    Measurement of cutting edge temperature in drilling2012Ingår i: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 3, s. 531-536Artikel i tidskrift (Refereegranskat)
    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.

  • 34.
    Beno, Tomas
    et al.
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap, Avd för maskinteknik. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Isaksson, Marina
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap, Avd för maskinteknik.
    Pejryd, Lars
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap, Avd för maskinteknik.
    Investigation of Minimal Quantity Cooling Lubrication in Turning of Inconel 7182007Ingår i: Proceedings of the 3rd International Conference on Tribology in Manufacturing Processes: ICTMP 2007, Yokohama, Japan 24-26 September, 2007, s. 281-286Konferensbidrag (Övrigt vetenskapligt)
  • 35.
    Beno, Tomas
    et al.
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap, Avd för maskinteknik. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Isaksson, Marina
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap, Avd för maskinteknik.
    Pejryd, Lars
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap, Avd för maskinteknik. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Investigation of Minimal Quantity Lubrication in Turning of Waspalloy2007Ingår i: Advances in Life Cycle Engineering for Sustainable Manufacturing Businesses: Proceedings of the 14th CIRP Conference on Life Cycle Engineering, Waseda University, Tokyo, Japan, June 11th-13th, 2007, Springer , 2007, s. 305-310Konferensbidrag (Refereegranskat)
  • 36.
    Beno, Tomas
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Repo, Jari
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för maskinteknik och naturvetenskap.
    Pejryd, Lars
    Örebro Universitet.
    The Use of Machine Tool Internal Encoders as Sensors in a Process Monitoring System2013Ingår i: International Journal of Automation Technology, ISSN 1881-7629, E-ISSN 1883-8022, Vol. 7, nr 4, s. 410-417Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Tool wear in machining changes the geometry of the cutting edges, which affects the direction and amplitudes of the cutting force components and the dynamics in the machining process. These changes in the forces and dynamics are picked up by the internal encoders and thus can be used for monitoring of changes in process conditions. This paper presents an approach for the monitoring of a multi-tooth milling process. The method is based on the direct measurement of the output from the position encoders available in the machine tool and the application of advanced signal analysis methods.

    The paper investigates repeatability of the developed method and discusses how to implement this in a process monitoring and control system. The results of this work show that various signal features which are correlated with tool wear can be extracted from the first few oscillating components, representing the low-frequency components, of the machine axes velocity signatures. The responses from the position encoders exhibit good repeatability, especially short term repeatability while the long-term repeatability is more unreliable.

  • 37.
    Bhardwaj, Sanjay
    et al.
    International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Hyderabad, India.
    Padmanabham, G.
    International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Hyderabad, India.
    Jain, Karuna
    National Institute of Industrial Engineering (NITIE), Mumbai, India.
    Srinivasa Rao, D.
    International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Hyderabad, India.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Technology commercialization in advanced materials sector: Indian context2017Ingår i: Journal of Intellectual Property Rights, ISSN 0971-7544, E-ISSN 0975-1076, Vol. 22, nr 3, s. 154-167Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study is aimed at developing insights into the Technology Value Chain (TVC) of advanced materials-based technologies using a scenario in which technology has been transferred by a Research and Technology Organization (RTO) to a Small and Medium Enterprise (SME) in the Indian context. A Conceptual Theoretical Model (CTM) using constructs from existing TVC models is used as a basis for the case study described in this paper. This model is refined using actual evidence from an Indian RTO - the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Hyderabad. The TVC of ARCI’s proprietary Detonation Spray Coating (DSC) technology is used to expand upon the CTM as well as to provide new insights wherever possible. The TVC adopted for DSC includes technology incubation and proof of concept in advance of transferring the technology. These strategies, aided by government funding of the technology recipient companies, were observed to play an important role in successful commercialization. © 2017, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.

  • 38.
    Björklund, Stefan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Förbättrad lönsamhet för biogasanläggningar genom beläggning av knivar2016Konferensbidrag (Övrigt vetenskapligt)
  • 39.
    Björklund, Stefan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Goel, Sneha
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Function-dependent coating architectures by hybrid powder-suspension plasma spraying: Injector design, processing and concept validation2018Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 142, s. 56-65Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The attractive properties achieved by Suspension Plasma Spraying (SPS), combined with the availability of high throughput capable plasma spray systems that permit axial feeding, provide encouragement to explore use of suspensions for next generation functional applications. This paper deals with realization of coatings with various pre-determined function-dependent architectures by employing a hybrid powder-suspension feedstock. Some illustrative application-relevant coating architecture designs are discussed, along with the specific benefits that can accrue by deploying a multi-scale powder-suspension feedstock combination. An elegant feedstock delivery arrangement to enable either simultaneous or sequential feeding of powders and suspensions to enable convenient processing of coatings with desired architectures is presented. As proof-of-concept, deposition of layered, composite and functionally graded coatings using the above system is also demonstrated using appropriate case studies

  • 40.
    Bonilla Hernández, Ana Esther
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW). GKN Aerospace Engine Systems AB, Trollhättan, Sweden.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Fredriksson, Claes
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för Industriell ekonomi, Elektro- och Maskinteknik.
    Energy and Cost Estimation of a Feature-based Machining Operation on HRSA2017Ingår i: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 61, nr Supplement C, s. 511-516Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Forward-looking manufacturing companies aim for sustainable production with low environmental footprint. This is true also for aerospace engine-makers, although their environmental impact mostly occurs during the use-phase of their products. Materials, such as Nickel alloys, are used for special applications where other materials will not withstand tough working conditions in terms of pressure and temperature. Heat Resistant Super Alloys are, however, considered difficult to machine and cutting tools will wear off rapidly. In this paper, a simple way to estimate the energy required, the cost and environmental footprint to produce a work piece using standard engineering software is presented. The results show that for a hypothetical 3 tonne work piece, Inconel 718 will be considerably cheaper and require less water but will require more energy, and has considerably larger CO2 footprint than Waspaloy.

  • 41.
    Bonilla Hernández, Ana Esther
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Repo, Jari
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser.
    Wretland, Anders
    GKN Aerospace Engine Systems AB, Trollhättan, Sweden.
    Analysis of Tool Utilization from Material Removal Rate Perspective2015Ingår i: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 29, s. 109-113Artikel i tidskrift (Refereegranskat)
    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.

  • 42.
    Bonilla Hernández, Ana Esther
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Repo, Jari
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser.
    Wretland, Anders
    GKN Aerospace Engine Systems AB, Trollhättan, Sweden.
    Integrated optimization model for cutting data selection based on maximal MRR and tool utilization in continuous machining operations2016Ingår i: CIRP - Journal of Manufacturing Science and Technology, ISSN 1755-5817, E-ISSN 1878-0016, Vol. 13, s. 46-50Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The search for increased productivity can be interpreted as the increase of material removal rate (MRR). Namely, increase of feed, depth of cut and/or cutting speed. The increase of any of these three variables, will increase the tool wear rate; therefore decreasing its tool life according to the same tool life criteria. This paper proposes an integrated model for efficient selection of cutting data for maximal MRR and maximal tool utilization. The results show that, it is possible to obtain a limited range of cutting parameters from where the CAM Programmer can select the cutting data assuring both objectives.

  • 43.
    Bonilla Hernández, Ana Esther
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Repo, Jari
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser.
    Wretland, Anders
    GKN Aerospace Engine Systems AB, Trollhättan, Sweden.
    Streamlining the CAM programming process by Lean Principles within the aerospace industryManuskript (preprint) (Övrigt vetenskapligt)
  • 44.
    Bonilla Hernández, Ana Esther
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW). GKN Aerospace Engine Systems AB, Flygmotorvagen 1, Trollhattan, 46138, Sweden.
    Lu, Tao
    University of Kentucky, Institute for Sustainable Manufacturing (ISM), Lexington, KY 40506, United States.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Fredriksson, Claes
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Jawahir, I. S.
    University of Kentucky, Institute for Sustainable Manufacturing (ISM), Lexington, KY 40506, United States.
    Process sustainability evaluation for manufacturing of a component with the 6R application2019Ingår i: Procedia Manufacturing, E-ISSN 2351-9789, Vol. 33, s. 546-553Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sustainability in manufacturing can be evaluated at product, process and system levels. The 6R methodology for sustainability enhancement in manufacturing processes includes: reduced use of materials, energy, water and other resources; reusing of products/components; recovery and recycling of materials/components; remanufacturing of products; and redesigning of products to utilize recovered materials/resources. Although manufacturing processes can be evaluated by their productivity, quality and cost, process sustainability assessment makes it a complete evaluation. This paper presents a 6R-based evaluation method for sustainable manufacturing in terms of specific metrics within six major metrics clusters: environmental impact, energy consumption, waste management, cost, resource utilization and society/personnel health/operational safety. Manufacturing processes such as casting, welding, turning, milling, drilling, grinding, etc., can be evaluated using this methodology. A case study for machining processes is presented as an example based on the proposed metrics. © 2019 The Authors. Published by Elsevier B.V.

  • 45.
    Chen, Ying
    et al.
    University of Manchester,School of Materials, M13 9PL, Manchester, United Kingdom.
    Zhang, Xun
    University of Manchester,School of Materials, M13 9PL, Manchester, United Kingdom.
    Zhao, Xiaofeng
    Shanghai Jiao Tong University, Shanghai Key Laboratory of Advanced High-Temperature Materials and Precision Forming, Shanghai, 200240, China.
    Markocsan, Nicolaie
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Nylén, Per
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Xiao, Ping
    University of Manchester,School of Materials, M13 9PL, Manchester, United Kingdom; Shanghai Jiao Tong University, Shanghai Key Laboratory of Advanced High-Temperature Materials and Precision Forming, Shanghai, 200240, China.
    Measurements of elastic modulus and fracture toughness of an air plasma sprayed thermal barrier coating using micro-cantilever bending2019Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 374, s. 12-20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The elastic modulus and fracture toughness of an air plasma sprayed thermal barrier coating (APS TBC) were measured using the micro-cantilever bending technique. The micro-cantilevers were machined by a focused ion beam with their central arms either parallel or normal to the bond coat/topcoat interface. Such orientations allowed direct measurements of both the in-plane and out-of-plane elastic moduli as well as mode I fracture toughness by bending. The calculated elastic modulus along the in-plane and out-of-plane direction is 144 GPa and 110 GPa, respectively, suggesting that the APS TBC is elastically anisotropic at microscale. The derived mode I fracture toughness along the plane parallel to the interface is 0.40 MPam. This relatively low toughness reflects the weak fracture resistance of the highly-flawed APS for short cracks at microscale. The measurements in this study can be incorporated into micromechanical life time prediction models of the APS TBCs. © 2019 Elsevier B.V.

  • 46.
    Das, Kallol
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Eynian, Mahdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Wretland, Anders
    GKN Aerospace Engine Systems AB, Trollhättan, Sweden.
    Effect of tool wear on quality in drilling of titaniumalloy Ti6Al4V, Part II: Microstructure and Microhardness2017Ingår i: High speed machining, E-ISSN 2299-3975, Vol. 3, s. 11-22Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Drilling of Ti6Al4V with worn tools can introduce superficial and easily measured features such as increase of cutting forces, entry and exit burrs and surface quality issues and defects. Such issues were presented in the part I of this paper. In part II, subsurface quality alterations,such as changes of the microstructure and microhardness variation is considered by preparing metallographic sections and measurement, mapping of the depth of grain deformation, and microhardness in these sections. Drastic changes in the microstructure and microhardness were found in sections drilled with drills with large wear lands,particularly in the dry cutting tests. These measurements emphasize the importance of detection of tool wear and ensuring coolant flow in drilling of holes in titanium components.

  • 47. Davies, P.
    et al.
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV). Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Institute of Structural Materials, College of Engineering, Swansea University, Bay Campus, Fabian Way, Swansea SA1 8EN, United Kingdom.
    Coleman, M.
    Institute of Structural Materials, College of Engineering, Swansea University, Bay Campus, Fabian Way, Swansea SA1 8EN, United Kingdom.
    Birosca, S.
    Institute of Structural Materials, College of Engineering, Swansea University, Bay Campus, Fabian Way, Swansea SA1 8EN, United Kingdom.
    The hierarchy of microstructure parameters affecting the tensile ductility in centrifugally cast and forged Ti-834 alloy during high temperature exposure in air2016Ingår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 117, s. 51-67Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ductility regression is the main concern in using Ti-834 titanium alloy at temperatures above 500 °C for aerospace applications. The reduction of ductility in titanium alloys at high temperatures is strongly correlated to the exposure time. In the current study the effect of prolonged exposure at 500 °C on the tensile ductility of two differently processed Ti-834 alloys was investigated. In order to simulate actual Ti-834 processing routes, forged and centrifugally cast materials were used. The tensile tests were conducted on various specimens exposed at 500 °C for 100, 200 and 500 h to observe microstructure feature changes. Moreover, the effect of microstructure, microtexture, α-case, α2 and silicide precipitate coarsening during high temperature exposure was studied thoroughly. The cast alloy was found to have a minimum ductility and failed at 1.8% strain after exposure at 500 °C/500 h when the α-case layer was retained during testing, whilst, the ductility of the forged alloy was unaffected. The effects of individual microstructural parameters on the ductility regression in Ti-834 alloy were quantified. The results showed that 7.1% strain differences between the cast and forged alloy are related to microstructural variations including; morphology, lath widths, grain size and shape, grain orientations and microtexture. A total of 9.6% strain loss was observed in centrifugally cast Ti-834 after aging at 500°C/500 h and quantified as follow; 3.6% due to α-case formation during high temperature exposure, 0.2% due to α2-precipitates coarsening, 4.4% due to further silicide formation and coarsening, 1.4% due to additional microstructure changes during high temperature exposure. Furthermore, silicide coarsening on α/β phase boundaries caused large void formation around the precipitates. A theoretical model supported by experimental observations for silicide precipitation in fully colony and duplex microstructures was established. The element partitioning during exposure caused Al and Ti depletion in the vicinity of the β phase in the lamellae, i.e., αs area. This resulted in lowering the strength of the alloy and facilitated the formation of Ti3(SiZr)2 precipitates. The Al depletion and nano-scale partitioning observed at the αs/β boundaries resulted in easy crack initiation and promoted propagation in the centrifugally cast colony microstructure and reduced the basal slip τcrss. Furthermore, silicides were not formed in αp (high Al, Ti and low Zr areas) in the forged duplex microstructure that promoted superior mechanical performance and ductility over the cast alloy.

    Graphical abstract

  • 48.
    Devotta, Ashwin
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Löf, Ronnie
    Sandvik Coromant AB, Sandviken, Sweden.
    FE Modelling and Characterization of Chip Curl in Nose Turning processIngår i: International Journal of Machining and Machinability of Materials, ISSN 1748-572XArtikel i tidskrift (Refereegranskat)
  • 49.
    Devotta, Ashwin Moris
    et al.
    Sandvik Coromant AB, Sandviken, Sweden.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Eynian, Mahdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Simulation-Based Product Development Framework for Cutting Tool Geometry Design2019Ingår i: Conference Proceedings: International Conference on Competitive Manufacturing, COMA19, presented at Stellenbosch Univerisy, January 30 - February 1 2019, Stellenbosch University, Stellenbosch, South Africa. / [ed] Dimitrov, D., Hagedorn-Hansen, D. & Von Leipzig, K., Stellenbosch University , 2019, s. 47-52Konferensbidrag (Refereegranskat)
    Abstract [en]

    Cutting tool geometry design has traditionally relied on experimental studies; while engineering simulations, to the level of industrial deployment, have been developed only in the last couple of decades. With the development of simulation capability across length scales from micro to macro,cutting tool geometry development includes engineering data development for its efficient utilization. This calls for the design of a simulation-based approach in the design of cutting tool geometry so that the engineering data can be generated for different machining applications (e.g.digital twin). In this study, the needs for engineering model development of different stages of cutting tool design evaluation is assessed. To this end, some of the previously developed engineering models have been evaluated for evaluation of chip form morphology in industrially relevant nose turning process, work piece material behavior modeling and damage modeling for the prediction of chip shape morphology. The study shows the possibility for the developed models to act as building blocks of a digital twin. It also shows the need for engineering model development for different aspects of cutting tool design, its advantages, limitations, and prospects.

  • 50.
    Devotta, Ashwin Moris
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW). R&D Turning, Sandvik Coromant, Sandviken.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Löf, Ronnie
    R&D Turning, Sandvik Coromant, Sandviken.
    Finite element modelling and characterisation of chip curl in nose turning process2017Ingår i: International Journal of Machining and Machinability of Materials, E-ISSN 1748-572X, Vol. 19, nr 3, s. 277-295Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Finite element (FE) modelling of machining provide valuable insights into its deformation mechanics. Evaluating an FE model predicted chip morphology requires characterisation of chip shape, chip curl and chip flow angles. In this study, a chip morphology characterisation methodology is developed using computed tomography (CT), high-speed imaging and Kharkevich model equations enabling evaluation of FE model’s chip morphology prediction accuracy. Chip formation process in nose turning of AISI 1045 steel is simulated using a 3D FE model for varying feed rate and depth of cut and evaluated against experimental investigations using the employed methodology. The study shows that the methodology is able to characterise chip morphology in nose turning process accurately and enables evaluation of FE model’s chip morphology prediction accuracy. This can enable the finite element model to be deployed in cutting tool design for chip breaker geometry design.

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