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  • 1.
    Ainegren, Mats
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Carlsson, Peter
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Tinnsten, Mats
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    The multi functional roller ski2012Konferansepaper (Fagfellevurdert)
  • 2.
    Ainegren, Mats
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Carlsson, Peter
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Tinnsten, Mats
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    The multifunctional roller ski2013Inngår i: Science and Nordic Skiing II / [ed] Hakkarainen A, Linnamo V, Lindinger S, University of Salzburg, University of Jyväskylä , 2013, s. 253-261Kapittel i bok, del av antologi (Fagfellevurdert)
  • 3.
    Botero, Carlos Alberto
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Koptyug, Andrey
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Jiménez-Piqué, Emilio
    Universitat Politècnica de Catalunya, Barcelona, Spain.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Microstructure and nanomechanical behavior of modified 316L-based materials fabricated using EBM2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Stainless steel 316L based materials modified by the additions of iron-based wear-resistant alloys (Colferoloy@ 103 and 139) used for thermal spray coatings applications were fabricated by EBM. Process parameters were tailored to fabricate compact specimens of 1cm3 in an Arcam A2 (Arcam AB, Mölndal, Sweden) at Mid Sweden University. Microstructural features of the materials obtained were characterized by OM and SEM in polished and etched samples. Nanoindentation tests carried out at different penetration depths were performed on selected areas of the polished specimens to evaluate the materials micro/nano mechanical behavior and to establish correlations with the observed microstructure.

  • 4.
    Botero Vega, Carlos Alberto
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Jiménez-Piqué, Emilio
    Universitat Politècnica de Catalunya, Barcelona.
    Roos, Stefan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Skoglund, Per
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Koptioug, Andrei
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Nanoindentation: a suitable tool in metal Additive Manufacturing2018Konferansepaper (Fagfellevurdert)
  • 5.
    Bäckström, Mikael
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Dahlén, Leon
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Ebrahimzadeh, Reza
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Taylor Made Titanium Insoles in Alpine Ski Boots2009Inngår i: Asia-Pasific Congress on Sports Technology, 2009Konferansepaper (Fagfellevurdert)
  • 6.
    Bäckström, Mikael
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Kuzmin, Leonid
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Wiklund, Håkan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Critical Factors Influencing Loss of Time after Shooting - A Case Study Performed During the 2008 IBU Biathlon World Championships2009Inngår i: The Impact of Technology on Sport III, 2009, s. 33-37Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    The final result during a biathlon race is a composition of skiing, shooting and in some cases penalty time or rounds. One of the most decisive parts of the competition is the shooting component. The shooting component itself can be subdivided into separate parts: Actions just before shooting, the shooting itself and actions after the shooting. In the case of a slow approach to the firing line partially caused by dismounting of ski poles, time loss is tactically accepted by some skiers – heart rate decreases and a mental focus can be obtained. A slow departure from the firing line and the subsequent loss of time is on the contrary absolutely not desirable. A part of the lost time after shooting is observed to be related to mounting the ski poles. Modern ski poles can be divided into three groups of strap systems: 1. Simple loop; 2. Strap with Velcro fastener; 3. Click-in (typically Leki).

    The paper presents a case study aimed at finding how the ski pole strapping system influences time loss after shooting. The study was performed during the IBU Biathlon World Championship 2008 in Östersund, Sweden. Time measurements were made over a defined distance allowing the athletes to approach cruising speed after the last shot in a series. The measurements for each athlete have been normalized relative his/her racing performance. The results clearly indicate time differences between strap systems. In some cases the differences could mean achieving podium place or not.

  • 7.
    Bäckström, Mikael
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Kuzmin, Leonid
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Influencing factors on time-loss after shooting in Biathlon2011Inngår i: Moderns systems for application in Biathlon, Omck: Russian Sports Federation , 2011, s. 154-159Konferansepaper (Fagfellevurdert)
  • 8.
    Bäckström, Mikael
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Tinnsten, Mats
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Koptyug, Andrey
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Carlsson, Peter
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Danvind, Jonas
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Wiklund, Håkan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Sports Technology Education at Mid Sweden University2013Inngår i: 6TH ASIA-PACIFIC CONGRESS ON SPORTS TECHNOLOGY (APCST), Elsevier, 2013, Vol. 60, s. 214-219Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In present paper we would like to share some experiences of building new education in Sports Technology at MidSweden University and the results of 10 years of successfully running it in Östersund. The Sports Technologyeducation at Mid Sweden University started at Campus Östersund in 2003 as a part of the curriculum of theEngineering Department. This specialization was initially at the three-year Bachelor level, and later it was extendedto an additional two-year Master level. Aiming at the quality of Sports Technology education, three keystones areunderlying its process, representing the solid knowledge base, capacity to be flexible in problem solving and the usean innovative approaches. The Department unites researches with a background in both natural sciences andengineering disciplines, having a wide experience of working with and within the industry, equally active in researchand teaching. The unique constellation of the profiles forming the Department include not only the SportsTech®group, being “the backbone”, but also the Ecology and Eco-technology, and Quality Technology groups bringing theexcellence and extra competence needed to assure the quality of the Sports Technology education. We were the firsthigher education institution in Sweden to give this kind of education program and now some other SwedishUniversities have followed us. Our success can be measured by a number of graduates taking good jobs in theindustry. We also enjoy a steady flow of new students coming from all parts of Sweden, and Sports Technologyeducation stays among the most desirable ones in the country.

  • 9.
    Cronskär, Marie
    et al.
    AIM Sweden.
    Legrell, Pererik
    Norrlands universitetssjukhus.
    Tidehag, Per
    Norrlands universitetssjukhus.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Dental Implant Manufacturing using Electron Beam Melting – Geometry Deviation from Intraoral Scanning and from Cone Beam Computed Tomography2016Inngår i: EBAM 2016: 1st International Conference on Electron Beam Additive Manufacturing, 2016Konferansepaper (Fagfellevurdert)
  • 10.
    Cronskär, Marie
    et al.
    AIM Sweden.
    Legrell, Pererik
    Norrlands universitetssjukhus.
    Tidehag, Per
    Norrlands universitetssjukhus.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Dental Implant Manufacturing using Electron Beam Melting – Geometry Deviation from Intraoral Scanning and from Cone Beam Computed Tomography2016Konferansepaper (Annet vitenskapelig)
  • 11.
    Cronskär, Marie
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Implementation of digital design and solid free-form fabrication for customization of implants in trauma orthopaedics2012Inngår i: Journal of medical and biological engineering, ISSN 1609-0985, Vol. 32, nr 2, s. 91-96Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bone plates for the fixation of complex fractures in proximity to joints often have to be reshaped to follow the bone contour. Good adhesion of the screws in areas where the bone is osteoporotic is also a challenge. One possible solution to these issues is to tailor-make plates by creating a digital three-dimensional model of the fracture from a computed tomography (CT) scan, digitally reducing the fracture, designing a plate, and finally manufacturing it directly from the digital model with solid free-form fabrication (SFF) technology. This study designs a custom plate for a distal tibia fracture, and investigates and refines the procedure from the CT scan to the final implant, with the aim of making it usable in trauma orthopaedics. The bone plate is manufactured using electron beam melting (EBM) technology. The challenges of bone plate design using digitalization and SFF are discussed. The virtual models created by the engineer while digitally reducing the fracture and modeling the plate are valuable for the physician while planning the surgery. A combination of surgery planning and digital plate design improves the surgeon's preparations and ensures correspondence between the plan and the designed implant. The proposed procedure, with the approximate required time in brackets, includes the separation of bone in the DICOM file (60 min), the reduction of fracture (5-30 min), revision (30 min), modelling of the plate (30-120 min), confirmation (30 min), manufacturing with SFF (10 h), post-processing (60 min), and finally cleaning and sterilization (90 min). The whole procedure requires about three working days.

  • 12.
    Cronskär, Marie
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Production of Customized Hip Stem Prostheses: a Comparison Between Machining and Additive Manufacturing2013Inngår i: Rapid prototyping journal, ISSN 1355-2546, E-ISSN 1758-7670, Vol. 19, nr 5, s. 365-372Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose - The purpose of this paper is to study the use of the additive manufacturing (AM) method, electron beam melting (EBM), for manufacturing of customized hip stems. The aim is to investigate EBM's feasibility and commercial potential in comparison with conventional machining, and to map out advantages and drawbacks of using EBM in this application. One part of the study concerns the influence on the fatigue properties of the material, when using the raw surface directly from the EBM machine, in parts of the implant.Design/methodology/approach - The research is based on a case study of manufacturing a batch of seven individually adapted hip stems. The stems were manufactured both with conventional machining and with EBM technology and the methods were compared according to the costs of materials, time for file preparation and manufacturing. In order to enhance bone ingrowths in the medial part of the stem, the raw surface from EBM manufacturing is used in that area and initial fatigue studies were performed, to get indications on how this surface influences the fatigue properties.Findings - The cost reduction due to using EBM in this study was 35 per cent. Fatigue tests comparing milled test bars with raw surfaced bars indicate a reduction of the fatigue limit by using the coarse surface.Originality/value - The paper presents a detailed comparison of EBM and conventional machining, not seen in earlier research. The fatigue tests of raw EBM-surfaces are interesting since the raw surface has shown to enhance bone ingrowths and therefore is suitable to use in some medical applications.

  • 13.
    Cronskär, Marie
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Koptioug, Andrei
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Application of electron beam melting to titanium hip stem Implants2008Inngår i: / [ed] Katalinic, B., Vienna: DAAAM International Vienna , 2008, s. 1559-1560Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Free Form Fabrication Process (FFF) is nowadays an accepted technology widely used for prototyping and manufacturing. However, it is still in an expansive phase and new applications like direct manufacturing of implants are evolving continuously. Present work describes the possibilities provided by the electron beam melting (EBM) method for orthopedics; in particular hip stem implant manufacturing. The conventional machining used for individually adapted prostheses typically involves advanced milling with the drawback of removing up to 80% of the material. This paper addresses the economic feasibility of using an additive approach for the manufacturing of typical orthopedic implants. The studied implants were manufactured from biocompatible Ti-6Al-4V alloy using both EBM and conventional CNC technologies and compared according to material consumption, manufacturing time and cost.

  • 14.
    Cronskär, Marie
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Nilsson, K-G
    Samuelsson, B
    Patient-specific bone plates for clavicle fractures: Design, manufacturing and strength analysisManuskript (preprint) (Annet vitenskapelig)
  • 15.
    Cronskär, Marie
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Nilsson, Kjell G.
    Umea Univ, Dept Surg & Perioperat Sci Orthopaed, S-90187 Umea, Sweden.
    Samuelsson, Börje
    Ostersunds Sjukhus, Dept Orthopaed, Ortopedmottagningen, S-83183 Ostersund, Sweden.
    Patient-Specific Clavicle Reconstruction Using Digital Design and Additive Manufacturing2015Inngår i: Journal of mechanical design (1990), ISSN 1050-0472, E-ISSN 1528-9001, Vol. 137, nr 11, artikkel-id 111418Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There is a trend toward operative treatment for certain types of clavicle fractures and these are usually treated with plate osteosynthesis. The subcutaneous location of the clavicle makes the plate fit important, but the clavicle has a complex shape, which varies greatly between individuals and hence standard plates often have a poor fit. Using computed tomography (CT) based design, the plate contour and screw positioning can be optimized to the actual case. A method for patient-specific plating using design based on CT-data, additive manufacturing (AM), and postprocessing was initially evaluated through three case studies, and the plate fit on the reduced fracture was tested during surgery (then replaced by commercial plates). In all three cases, the plates had an adequate fit on the reduced fracture. The time span from CT scan of the fracture to final implant was two days. An approach to achieve functional design and screw-hole positioning was initiated. These initial trials of patient-specific clavicle plating using AM indicate the potential for a smoother plate with optimized screw positioning. Further, the approach facilitates the surgeon's work and operating time can be saved.

  • 16.
    Cronskär, Marie
    et al.
    AIM Sweden.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Hamberg, Åke
    Östersund hospital.
    Samuelsson, Börje
    Östersund hospital.
    Nilsson, Kjell G
    Norrlands universitetssjukhus.
    Custom design and additive manufacturingof orthopedic implants and medical models in titanium and plastics2016Konferansepaper (Fagfellevurdert)
  • 17. Dérand, Per
    et al.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Hirsch, Jan-M
    Imaging, virtual planning, design and production of patient specific implants and clinical validation in cranio-maxillo-facial surgery2012Inngår i: Cranial maxillofacial Trauma and Reconstruction, ISSN 1943-3875, Vol. 5, nr 3, s. 137-144Artikkel i tidsskrift (Fagfellevurdert)
  • 18.
    Ek, Rebecca
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Carlsson, Peter
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    The Effect of EBM Process Parameters upon Surface Roughness2016Inngår i: Rapid prototyping journal, ISSN 1355-2546, E-ISSN 1758-7670, Vol. 22, nr 3, s. 495-503Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose-The surface roughness of products manufactured using the additive manufacturing (AM) technology of electron beam melting (EBM) has a special characteristic. Different product applications can demand rougher or finer surface structure, so the purpose of this study is to investigate the process parameters of EBM to find out how they affect surface roughness. Design/methodology/approach-EBM uses metal powder to manufacture metal parts. A design of experiment plan was used to describe the effects of the process parameters on the average surface roughness of vertical surfaces. Findings-The most important electron beam setting for surface roughness, accorDing to this study, is a combination of speed and current in the contours. The second most important parameter is contour offset. The interaction between the number of contours and contour offset also appears to be important, as it shows a much higher probability of being active than any other interaction. The results show that the line offset is not important when using contours. Research limitations/implications-This study examined contour offset, number of contours, speed in combination with current and line offset, which are process parameters controlling the electron beam. Practical implications-The surface properties could have an impact on the product's performance. A reduction in surface processing will not only save time and money but also reduce the environmental impact. Originality/value-Surface properties are important for many products. New themes containing process parameters have to be developed when introducing new materials to EBM manufacturing. During this process, it is very important to understand how the electron beam affects the melt pool.

  • 19.
    Frisk, Karin
    et al.
    Swerea KIMAB, Kista.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Koptyug, Andrey
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Petterson, Niklas
    Swerea KIMAB, Kista.
    Persson, Daniel
    Swerea KIMAB, Kista.
    Leicht, Alexander
    Chalmers.
    Vattur Sundaram, Maheswaran
    Chalmers.
    Hrhya, Eduard
    Chalmers.
    Nyborg, Lars
    Chalmers.
    Ahlfors, Magnus
    Quintus Technologies, Västerås.
    Characterisation Of EBM-built Shelled Samples of Ti6Al4V Compacted by HIP2016Konferansepaper (Fagfellevurdert)
  • 20.
    Hirsch, J
    et al.
    Akademiska sjukhuset.
    Carlbom, I
    Uppsala universitet.
    Dérand, P
    Skåne universitetssjukhus.
    Nysjö, F
    Uppsala universitet.
    Nyström, I
    Uppsala universitet.
    Olsson, P
    Uppsala universitet.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Virtual planning, additive manufacturing of biomaterials and real time reconstructive maxillofacial surgery2013Konferansepaper (Fagfellevurdert)
  • 21. Hirsch, Jan-M
    et al.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Gamstedt, Kristofer
    Virtual planning of reconstructions, production of individualized implants and transfer of the plan to the operating room in CMF surgery2012Konferansepaper (Annet vitenskapelig)
  • 22.
    Hirsch, Jan-Michael
    et al.
    Uppsala university.
    Dérand, Per
    University hospital of Lund.
    Gamstedt, Kristofer
    Uppsala university.
    Huo, Jinxing
    Uppsala university.
    Omar, Omar
    Gothenburg university.
    Palmquist, Anders
    Gothenburg university.
    Thor, Andreas
    Uppsala university.
    Nysjö, Fredrik
    Uppsala university.
    Nysjö, J
    Uppsala university.
    Nyström, Ingela
    Uppsala university.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    3D printed titanium implants i Maxillofacial surgery2016Konferansepaper (Fagfellevurdert)
  • 23.
    Holmberg, Joakim
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik, fysik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik, fysik och matematik.
    VerOpt - MATLAB Driven Versatile Optimization2001Inngår i: Program and proceedings for the Nordic MATLAB Conference Oslo, October 17-18, 2001, Trondheim: Comsol , 2001, s. 207-212Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    VerOpt, a MATLAB driven versatile optimization environment, enables the choice of a suitable optimization routine, parallelization over TCP/IP and the use of external solvers. VerOpt is the result of working towards the creation of a versatile yet effective environment for applied optimization studies. This paper presents the concepts behind VerOpt, including how and why we use parallelization, and the lessons learnt when using external solvers. The paper also gives a comparison of implemented optimization routines when applied to test problems. Currently, links to three external solvers are implemented. Two of them come from the commercial software market for engineering solutions: ANSYS (version 5.6 University High), a general purpose FE-code and C-MOLD (version 2000.7.1), a code for injection molding. The third solver is from the academic world, AnyBody, a code for biomechanical studies. The implemented optimization routines referred to are Method of Moving Asymptotes (MMA), Simulated Annealing (SA) and a genetic algorithm (GA). The MMA is a gradient-based algorithm whereas the other two can be classified as stochastic. The results of the comparison of the implemented optimization routines, in which �fmincon� from the MATLAB Optimization Toolbox is also used, show that MMA is generally the fastest routine, but does not always find the best solution. However, in test cases when parallelization is used the comparison is not ideal, since the parallelization procedures for the algorithms are not equivalent. When optimization routines are based on numerically computed gradients, such as MMA, they are embarrassingly parallel. This is because the gradients are independent of each other, which makes it possible to compute them simultaneously, but on different processors. For a stochastic routine such as SA a different approach is needed. In our case we have used a simple form of domain decomposition. An interesting result is that, in the test case involving ANSYS, we found that using ANSYS alone, as solver as well as optimizer, did not give such a good solution as using VerOpt. A clear future development is to add a greater number of different types of optimization routines. A possible future development is to transform VerOpt into something that is more akin to a regular style MATLAB Toolbox. Irrespective of this development, VerOpt will be a significant aid for education as well as research in applied optimization. It will also serve the authors as the environment for further research in the fields of injection molding and biomechanics.

  • 24.
    Huo, Jinxing
    et al.
    Division of Applied Mechanics, Department of Engineering Sciences, Uppsala University, Sweden.
    Derand, Per
    Department of Oral and Maxillofacial Surgery, Skåne University Hospital, Sweden.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Hirsch, Jan-Michael
    Department of Surgical Sciences, Oral & Maxillofacial Surgery, Uppsala University Sweden.
    Gamstedt, E. Kristofer
    Division of Applied Mechanics, Department of Engineering Sciences, Uppsala University.
    Failure location prediction by finite element analysis for an additive manufactured mandible implant2015Inngår i: Medical Engineering & Physics, ISSN 1350-4533, Vol. 37, nr 9, s. 862-869Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to reconstruct a patient with a bone defect in the mandible, a porous scaffold attached to a plate, both in a titanium alloy, was designed and manufactured using additive manufacturing. Regrettably, the implant fractured in vivo several months after surgery. The aim of this study was to investigate the failure of the implant and show a way of predicting the mechanical properties of the implant before surgery. All computed tomography data of the patient were preprocessed to remove metallic artefacts with metal deletion technique before mandible geometry reconstruction. The three-dimensional geometry of the patient's mandible was also reconstructed, and the implant was fixed to the bone model with screws in Mimics medical imaging software. A finite element model was established from the assembly of the mandible and the implant to study stresses developed during mastication. The stress distribution in the load-bearing plate was computed, and the location of main stress concentration in the plate was determined. Comparison between the fracture region and the location of the stress concentration shows that finite element analysis could serve as a tool for optimizing the design of mandible implants.

  • 25.
    Huo, Jinxing
    et al.
    Uppsala university.
    Hirsch, Jan-Michael
    Uppsala university.
    Dérand, Per
    Skåne university hospital.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Gamstedt, Kristofer
    Uppsala university.
    Finite element investigation of the in-vivo failure of a titanium alloy human jaw implant2014Konferansepaper (Fagfellevurdert)
  • 26.
    Israelsson, Björn
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik, fysik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik, fysik och matematik.
    CAE and Rapid Prototyping Integrated in Product Marketing: A Novel Method for the Plastic Manufacturing Industry in the County of Jämtland2004Inngår i: Moldex3D European User’s Meeting, Billund, Denmark, September 2004., 2004Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    This paper describes a successful co-operation between the university and the industry in the county of Jämtland, Sweden. The project was initiated by the plastic manufacturing company Essge-Plast who wanted to incorporate Mid Sweden University in one of their in-house projects. The task was to design a new type of bracket and information plate for Stockholm�s burial grounds. Different kind of CAE software was used in order to visualize the concept and to simulate the production of the plastic part. Also, rapid prototyping was used in order to confirm the design of the bracket and the plate.

  • 27.
    Klingvall Ek, Rebecca
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Fatigue properties of electrochemical polished and hot isostatic pressed Ti6A14V manufactured by electron beam meltingInngår i: Artikkel i tidsskrift (Fagfellevurdert)
  • 28.
    Klingvall Ek, Rebecca
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Fatigue properties of Ti-6Al-4V manufactured using electron beam melting2017Inngår i: Proceedings Euro PM 2017: International Powder Metallurgy Congress and Exhibition 2017, Brussels: EPMA European Powder Metallurgy Association , 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The interest in powder bed fusion additive manufacturing methods, such as electron beam melting (EBM), is increasing constantly and main business areas driving the development are aerospace and implant manufacturers. EBM manufactured parts have a rather coarse surface roughness mainly originating from the layer thickness and the powder grains melted by the electron beam. Thus, there is an interest in understanding how the surface properties influences the fatigue performance of the material. In this study, EBM manufactured Ti-6Al-4V was investigated at high cycle fatigue using rotating beam and different types of specimens regarding geometry, as-built and hot isostatic pressing (HIP) post-processing were evaluated. The results confirm that as-built surfaces affect the fatigue limit and a small size specimen geometry for rotating beam fatigue testing is proposed as a part of material and process verification.

  • 29.
    Klingvall Ek, Rebecca
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Influence of the surface topography of additive manufactured Ti6A14V on fatigue and calculations of the stress concentration factorInngår i: Artikkel i tidsskrift (Fagfellevurdert)
  • 30.
    Klingvall Ek, Rebecca
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Hong, Jaan
    Uppsala University, Uppsala.
    Thor, Andreas
    Uppsala University, Uppsala.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Micro- to Macroroughness of Additively Manufactured Titanium Implants in Terms of Coagulation and Contact Activation2017Inngår i: International Journal of Oral & Maxillofacial Implants, ISSN 0882-2786, E-ISSN 1942-4434, Vol. 32, nr 3, s. 565-574Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: This study aimed to evaluate how as-built electron beam melting (EBM) surface properties affect the onset of blood coagulation. The properties of EBM-manufactured implant surfaces for placement have, until now, remained largely unexplored in literature. Implants with conventional designs and custom-made implants have been manufactured using EBM technology and later placed into the human body. Many of the conventional implants used today, such as dental implants, display modified surfaces to optimize bone ingrowth, whereas custom-made implants, by and large, have machined surfaces. However, titanium in itself demonstrates good material properties for the purpose of bone ingrowth. Materials and Methods: Specimens manufactured using EBM were selected according to their surface roughness and process parameters. EBM-produced specimens, conventional machined titanium surfaces, as well as PVC surfaces for control were evaluated using the slide chamber model. Results: A significant increase in activation was found, in all factors evaluated, between the machined samples and EBM-manufactured samples. The results show that EBM-manufactured implants with as-built surfaces augment the thrombogenic properties. Conclusion: EBM that uses Ti6Al4V powder appears to be a good manufacturing solution for load-bearing implants with bone anchorage. The as-built surfaces can be used "as is" for direct bone contact, although any surface treatment available for conventional implants can be performed on EBM-manufactured implants with a conventional design.

  • 31.
    Koptioug, Andrei
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    3D-printing: a future “magic wand” for global manufacturing. How can we benefit from it today for sports and health care?2017Inngår i: Proceedings of the 5th International Congress on Sport Sciences Research and Technology Support, icSPORTS / [ed] Jan Cabri, Pedro Pezarat Correia, INSTICC Press, 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    3D-printing, or as it is also known, additive manufacturing (AM), is promising to be one of the determining manufacturing technologies of the present century. It is not a single technology but a family of rather different ones common in the way components are made, adding materials layer by layer. Additive manufacturing is already quite competitive to existing and well established technologies, but it also can provide unprecedented flexibility and complexity of shapes making components from the materials as different as cheese, chocolate and cream, live cells, concrete, polymers and metal. Many more materials we were not even thinking about few years ago are also becoming available in additive manufacturing, making it really believable that “only the sky is the limit”. During the time available for the keynote lecture, we will analyze the present position of AM in relation to other technologies, the features that make it so promising and its influence upon the part of our life we call sports and health, using the examples relevant to the Congress areas from computer systems to sports performance. Out of all enormities of materials available for different representatives of this manufacturing family we will concentrate at polymers and metals. AM technologies working with these two material families are already providing some unique solutions within the application areas relevant to the Congress' scope. We will also talk about some limitations inherent to the AM in polymers and metals to have the awareness that though the limit is somewhere “high in the sky”, it still exists.

  • 32.
    Koptioug, Andrei
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Botero Vega, Carlos Alberto
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Popov, Vladimir
    Israel Institute of Metals, Technion R&D Foundation, Technion City, 3200003, Haifa, Israel.
    Unique material compositions obtained by Electron beam melting of blended powders2018Inngår i: Euro PM2018 Proceedings, European Powder Metallurgy Association, EPMA , 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Today powder bed fusion based (PBF) additive manufacturing (AM) methods in metallic materials mainly employ pre-alloyed precursor powders. It was even somehow assumed that in situ alloying of the blended powders will not be effective and such PBF processing will not yield any valuable materials. Recent studies carried out both for laser- and electron beam- based PBF have demonstrated possibilities of using precursors blended from both elemental and alloyed powders. We also demonstrate that composites and alloys indeed can be manufactured from a range of different pre-blended powders with Electron Beam Melting (EBM). It is also possible achieving both composites and alloys by design in different parts of the manufactured components by varying the beam energy deposition strategy. Using sequentially fed precursor powders together with a new powder delivery system also allows manufacturing of the functionally graded materials with gradual composition variation. Blended powder precursors and sequential powder feeding should provide opportunities of manufacturing components with changing composition and material properties in a single manufacturing process. It makes possible modern industrial manufacturing of materials similar to Damascus steels, and other composites and composite-like materials in combinations with alloyed and gradient sections by choice in different parts of components.  

  • 33.
    Koptyug, Andrey
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Bergemann, Claudia
    University Medical Center Rostock, Dept. of Cell Biology, Schillingallee 69, D-18057 Rostock, Germany.
    Lange, Regina
    Interface Research Group, Institute for Electronic Appliances and Circuits, University of Rostock, A.-Einstein-Str. 2, D-18059 Rostock, Germany.
    Jaggi, Victor-Emanuel
    University of Applied Sciences Northwestern Switzerland FHNW, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz, Switzerland.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Nebe, J. Barbara
    University Medical Center Rostock, Dept. of Cell Biology, Schillingallee 69, D-18057 Rostock, Germany.
    Osteoblast Ingrowth into Titanium Scaffolds made by Electron Beam Melting2014Inngår i: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 783-786, s. 1292-1297Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Present paper describes early findings from the study of Ti-6Al-4V scaffolds additively manufactured using electron beam melting (EBM®) technology and the influence of surface topography on the initial stages of cell acceptance. The surface topography of the components made by additive manufacturing (AM) processes including EBM® are often hard to control within the desired feature size range without post-processing. Two groups of experiments studying the behavior of human osteoblast-like cells (MG63) on samples with different surface roughness were carried out in vitro: Ti-6Al-4V samples only powder-blasted, and Ti-6Al-4V samples additionally electrochemically polished. The cell migration into powder-blasted Ti-6Al-4V 3D scaffolds with different shapes and dimensions of the lattice structures were studied.

  • 34.
    Koptyug, Andrey
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Tin Man- Making Spare Parts for Human Body2012Inngår i: Science First Hand, ISSN 1810-3960, Vol. 44, nr 2, s. 45-57Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    In this paper we would like to illustrate the present and future of additive manufacturing technologies in medicine, in particular when helping the humanity to acquire some needed "spare parts", using some examples provided by the Sports Technology (SportsTech) Group at the Department of Engineering and Sustainable Development of the Mid Sweden University.

  • 35.
    Koptyug, Andrey
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Backstrom, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Klingvall, Rebecca
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Electron Beam Melting: Moving from Macro- to Micro- and Nanoscale2012Inngår i: Materials Science Forum, Switzerland: Trans Tech Publications Inc., 2012, Vol. 706-709, s. 532-537Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents some results achieved in the biomedical applications of the EBM® technology, and describes the resolved and unresolved challenges presented by modern medical implant manufacturing. In particular it outlines the issues related to the cellular structure design and metal surface modification. Moving to precision control of the metal surface at a microand sub-micrometer scale is a serious challenge to the EBM® processing, because it uses the powder with average grain size of about 0.04 to 0.1 mm. Though manufacturing of components with solidmesh geometry and porous surfaces using EBM® is quite possible, post- processing (for example chemical or electrochemical) is needed to achieve desired control of the surface at smaller scales to realize full potential of the technology for biomedical applications.

  • 36.
    Koptyug, Andrey
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Multiscale surface structuring of the biomedical implants manufactured in Electron Beam Melting technology: Demands, advances and challengesArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Paper discusses the challenges of additive manufacturing when multidimensional shape and surface feature control of the component on wide scale is essential, as it is for the manufacturing of the metallic biomedical implants. Paper also discusses most critical demands imposed by the biomedical implant manufacturing including implant surface roughness issues along with possible solution pathways, and gives some examples of the problems encountered and achievements reached in solving these challenges for the Ti6Al4V EBM®- manufactured components.

  • 37.
    Koptyug, Andrey
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    New Materials for Additive Manufacturing in Metal: Back to Basics?2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Advantages of Additive Manufacturing (AM) technologies benefit from the freedom of component shapes achievable in a single manufacturing process, short design-to-market times, and energy and material efficiency. AM in metal also allows for extremely high quality of the material, low residual stress in "as manufactured" parts (especially with Electron Beam Melting, EBM®), and gives promise of exciting new materials with unique composition and properties. Beam- based additive manufacturing in metal uses sources with extremely high energy density like lasers and electron beams resulting in fast melting-solidification dynamics. Materials produced at such conditions often have unique microstructure and properties, which allows speaking about new, non-stationary metallurgy. Knowledge of traditional metallurgical processes, which are mainly stationary, is often not adequate for understanding the processes involved with AM in metal, especially in cases of new materials. Along with some technological challenges this prevents fast growth of full-scale industrial application of AM. Though extensive research is carried out on new materials for AM, so far it is mainly centered at the development of process parameters for the materials already known from more traditional technologies. And at the moment it is an art rather than science as additive manufacturing in metal is far from being a “push-button” process. In order to develop future materials with required microstructure utilizing in full unique manufacturing conditions it is important to go “back to basics” and carefully study the processes involved. Present paper outlines some of the existing research and technology challenges relevant to the industrial applications of the beam-based AM in metal and possible pathways to solutions basing on multiple years of practical work.

     

  • 38.
    Koptyug, Andrey
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Cronskär, Marie
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Additive Manufacturing for Medical and Biomedical Applications: Advances and Challenges2014Inngår i: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, s. 1286-1291Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Additive Manufacturing (AM) has solidly established itself not only in rapid prototyping but also in industrial manufacturing. Its success is mainly determined by a possibility of manufacturing components with extremely complex shapes with minimal material waste. Rapid development of AM technologies includes processes using unique new materials, which in some cases is very hard or impossible to process any other way. Along with traditional industrial applications AM methods are becoming quite successful in biomedical applications, in particular in implant and special tools manufacturing. Here the capacity of AM technologies in producing components with complex geometric shapes is often brought to extreme.

    Certain issues today are preventing the AM methods taking its deserved place in medical and biomedical applications. Present work reports on the advances in further developing of AM technology, as well as in related post-processing, necessary to address the challenges presented by biomedical applications. Particular examples used are from Electron Beam Melting (EBM), one of the methods from the AM family.

  • 39.
    Koptyug, Andrey
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Fager Franzén, Sanna
    ARCAM AB.
    Dérand, Per
    Additive Manufacturing Technology Applications Targeting Practical Surgery2013Inngår i: International Journal of Life Science and Medical Research, ISSN 2226-4566, Vol. 3, nr 1, s. 15-24Artikkel i tidsskrift (Fagfellevurdert)
  • 40.
    Koptyug, Andrey
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Langlet, raham
    Exmet AB, Company.
    Bulk Metallic Glass Manufacturing Using Electron Beam Melting2013Inngår i: Proceedings from Additive Manufacturing & 3D Printing, Nottingham, UK, July 2013, Nottingham, UK, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Modern research into the Bulk Metallic Glass (BMG) manufacturing is driven by theinterest from multiple application areas, including engineering, technology andbiomedicine. Advantages and unique properties of these materials can potentiallyrevolutionise many areas of modern life. But manufacturing of even small BMGcomponents is quite complex and often expensive. Making large BMG samplesusing traditional manufacturing methods like casting is hardly possible at all. Coolingof the large bulky pieces is commonly too slow to allow for successful formation ofamorphous metal. Only the processes with extremely fast cooling rates will succeedin BMG formation. Thus only small or rather thin BMG components are commonlymanufactured today.Beam type additive technologies can provide the route for successful BMGmanufacturing. These methods use layer-by-layer component manufacturing, whenthe melting of the thin powder layers is carried out by the energy of sharply focusedlaser or electron beam. There are hopes that the heat transfer from the small meltareas to the bulk of the metal would provide cooling rates high enough for theamorphous state formation.Present paper reports on the first successful experiments on manufacturing ironbasedBMG samples using EBM® additive manufacturing process. Used iron-basedalloys (also known as amorphous steels) are significantly cheaper andenvironmentally more friendly than traditional rare- earth based compositions. EBM®equipment is very versatile allowing perfect control of the manufacturing process. Butthe number of influencing parameters to be adjusted and issues to be considered inorder to achieve successful BMG manufacturing is quite significant. Among the mostcritical issues are the powder composition and powder grain dimensions, layerthickness, average sample temperature, energy deposition rate, beam focus andmotion parameters etc.Few iron-based BMG samples from the pre-alloyed powder (two powders of thesame composition from two different suppliers) were manufactured at Mid-SwedenUniversity and are currently thoroughly studied. Present paper discusses in somedetails the process development for EBM® manufacturing of iron-based BMGs, firstresults and preliminary conclusions available at the moment.

  • 41.
    Koptyug, Andrey
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Bäckström, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Shen, Zhijian
    Stockholm University, Dept. of Materials and Environmental Chemistry.
    New Metallurgy of Additive Manufacturing in Metal: Experiences from the Material and Process Development with Electron Beam Melting Technology (EBM)2016Inngår i: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 879, s. 996-1001Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Additive manufacturing (AM) is becoming one of the most discussed modern technologies. Significant achievements of the AM in metals today are mainly connected to the unprecedented freedom of component shapes this technology allows. But full potential of these methods lies in the development of new materials designed to be used specifically with AM. Proper understanding of the AM process will open up new possibilities, where material and component properties can be specifically tailored by controlling the parameters throughout the whole manufacturing process. Present paper discusses the issues related to the beam melting technologies AM and electron beam welding (EBW). We are speaking of new direction in material science that can be termed “non-stationary metallurgy”, using the examples from material and process development for EBW, electron beam melting (EBM®) and other additive manufacturing methods.

  • 42.
    Leicht, Alexander
    et al.
    Chalmers.
    Shvab, Ruslan
    Chalmers.
    Hrhya, Eduard
    Chalmers.
    Nyborg, Lars
    Chalmers.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Characterization of virgin and recycled 316L powder used in additive manufacturing2016Konferansepaper (Fagfellevurdert)
  • 43.
    Leicht, Alexander
    et al.
    Chalmers.
    Vattur Sundaram, Maheswaran
    Chalmers.
    Yao, Yiming
    Chalmers.
    Hrhya, Eduard
    Chalmers.
    Nyborg, Lars
    Chalmers.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Koptyug, Andrey
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Frisk, Karin
    Swerea KIMAB.
    Ahlfors, Magnus
    Quintus Technologies.
    As-HIP Microstructure of EBM Fabricated Shell Components2016Inngår i: Proceedings of Wolrd PM2016 - AM - Properties of Lightweight Materials ll, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Electron Beam Melting (EBM) was used to build Ti-6Al-4V cylindrical shell samples with different wall thickness filled with powder. Built shell samples were HIPed and the difference in microstructure between the EBM-built walls and densified powder inside the shell components was studied as well as the cohesion between these two regions. Components characterization utilizing LOM and SEM+EBSD indicates that columnar grain growth was consistent before and after HIP in the EBM-built part of the components (walls), whereas the densified material in the center of the component had a fine isotropic microstructure, characteristic for HIPed material. The combination of EBM and HIP is shown to be an attractive way of manufacturing complex-shape full density components for high performance applications, involving shortening of built time in the EBM-processing and lead time in capsule fabrication for HIP.

  • 44.
    Mellin, Pelle
    et al.
    Swerea KIMAB, Kista.
    Magnusson, Hans
    Swerea KIMAB, Kista.
    Harlin, Peter
    Sandvik Materials Technology, Sandviken.
    Wikman, Stefan
    F4E, Barcelona, Spain.
    Olsén, Jon
    Stockholm University, Stockholm.
    Shen, Zhijian James
    Stockholm University, Stockholm.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Ålgårdh, Joakim
    Swerea KIMAB, Kista.
    Nyborg, Lars
    Chalmers University of Technology, Gothenburg.
    Bonding EBM-built blocks of 316L steel, using hot isostatic pressing2017Inngår i: Proceedings Euro PM 2017: International Powder Metallurgy Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    To enable production of the First Wall Beam in the ITER fusion reactor; we attempt to join EBM-built blocks of 316L, by Hot Isostatic Pressing (HIP). For highly critical components, EBM-built material is usually HIPed anyway to heal defects such as pores and cracks. Using HIP to simultaneously bond several print-jobs together into a larger component saves time and reduces manufacturing complexity. We found by carrying out this research, that fine surface roughness is an important enabler for a complete bond. The raw printed surfaces that are obtained straight from the Arcam machine (Ra = 19.2 μm) do not enable a good bond. Instead, traditional machining, which in this paper reached Ra = 2.0 μm, enabled a good bond. HIP parameters are also important. The best bond in this study was achieved after increasing holding time from 1 h to 2 h. 

  • 45.
    Olsén, Jon
    et al.
    Stockholm University.
    Koptioug, Andrei
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Saedi, Kamran
    Luleå university of Technology.
    Shen, Zhijian James
    Stockholm university.
    The Heterogenic Structure Formed During Electron Beam Melting of 316L Stainless Steel2018Konferansepaper (Fagfellevurdert)
  • 46.
    Olsén, Jon
    et al.
    Stockholm University.
    Shen, Zhijian
    Stockholm University.
    Liu, Leifeng
    University of Birmingham, Birmingham, United Kingdom.
    Koptyug, Andrey
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitets- och maskinteknik.
    Micro- and macro-structural heterogeneities in 316L stainless steel prepared by electron-beam melting2018Inngår i: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 141, s. 1-7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This is a study of the micro- and macrostructural variations in samples of stainless steel with the overall composition of the grade 316L, produced using electron beam melting. Electron beam melting is one of the processing methods under consideration for manufacturing some of the International Thermo- Nuclear Experimental Reactor In-Vessel components. Therefore further studies of the homogeneity of the material were conducted. Electron beam melting results in a complicated thermal history of the manufactured part giving a significant impact on the microstructure. A cellular structure that is often observed in samples prepared by selective laser melting was found in the top layers of the specimens. Further down, the structure changed until the cellular structure was almost non-existing, and the grain boundaries had become more pronounced. This revelation of a heterogeneous structure throughout the entire part is crucial for large-scale industrial applications like the Thermo- Nuclear Experimental Reactor to make sure that it is understood that the properties of the material might not be the same at every point, as well as to assure that the correct post-treatment is done. It is also exposed that a significant part of this change is due to molybdenum redistribution inside the sample when it diffuses from the cell boundaries into the cells, and into bigger agglomerates in the grain boundaries. This diffusion seems not to affect the microhardness of the samples. 

  • 47. Petrovic, V
    et al.
    Jordá, O
    Martin, A
    Rännar, Lars-Erik Rännar
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Dejanovic, Slavko
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Knowledge assisted Rapid Manufacturing, KARMA Project2011Konferansepaper (Fagfellevurdert)
  • 48.
    Roos, Stefan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Koptioug, Andrei
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Danvind, Jonas
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för kvalitetsteknik, maskinteknik och matematik.
    Characterization of 316ln lattice structures fabricated via electron beam melting2017Inngår i: Materials Science and Technology Conference and Exhibition 2017, MS and T 2017, Association for Iron and Steel Technology, AISTECH , 2017, s. 336-343Konferansepaper (Fagfellevurdert)
    Abstract [en]

    One of the promising application areas of additive manufacturing (AM) relates to light weight structures, including complex near net shape geometries and lattices. So far one of the limiting factors hampering wider industrial usage of AM technologies is the limited availability of processed materials. The aim of present study was to expand the previous success in electron beam melting (EBM®) manufacturing of 316LN bulk materials into thinner lattice structures thus further widening the application areas available for the method. Present paper reports on the initial results where lattice structures with octagonal basic cells were manufactured using EBM® and characterized using microscopy and compression testing. 

  • 49.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik, fysik och matematik.
    Efficient Cooling of FFF Injection Molding Tools with Conformal Cooling Channels,: An Introductory Analysis2003Inngår i: Advanced research in virtual and rapid prototyping: proceedings of the 1st International Conference on Advanced Research in Virtual and Rapid Prototyping, Leiria, Portugal, 1 - 4 October, 2003, Leiria: Escola Superior de Tecnologia e Gestão , 2003, s. 433-437Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Typically, the conventional machining techniques for the design of cooling layouts, in injection molding tools, are drilled straight bores placed around the tool cavity. Ejector pins, parting planes, cores, etc., make it impossible to gain an optimal cooling effect and the methods to improve the cooling, such as baffles and bubblers, are rather time-consuming and expensive. A numerical comparison of the efficiency between conventional cooling channel layouts, using straight holes and a baffle, and a free-form fabricated (FFF) layout was carried out considering cooling time and dimensional stability. The analyses showed a considerable improvement in both cooling time and dimensional stability in favor of FFF cooling channels. A reduction of the cycle time up to 67% was achieved with preserved, and even better tolerances on the dimensional stability.

  • 50.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    On Optimization of Injection Molding Cooling2008Doktoravhandling, med artikler (Annet vitenskapelig)
12 1 - 50 of 62
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