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  • 1.
    Botero Vega, Carlos Alberto
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Jiménez-Piqué, Emilio
    Universitat Politècnica de Catalunya, Barcelona.
    Roos, Stefan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Skoglund, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Koptioug, Andrei
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Nanoindentation: a suitable tool in metal Additive Manufacturing2018Conference paper (Refereed)
  • 2.
    Bäckström, Mikael
    Luleå University of Technology, Department of Physics and Mechanical Engineering.
    On Monitoring and Control of Machining Processes1999Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The thesis presents several aspects related to the industrial and academic activities associated with monitoring and control of the machining process and machine tools

    A survey of the industrial situation identified some key factors for a successful implementation of monitoring and control techniques. Applicable, relatively simple, systems for cutting-process monitoring and adaptive control are available on the commercial market today but the degree of industrial utilisation of the technique is low because the systems are experienced as hard to operate and use, and are at the same time considered unreliable. In order to promote a higher degree of industrial utilisation more work has to be devoted raising the performance of the system solutions.

    An Integrated Supervisory Process Control (ISPC) concept is presented as an approach dealing with multi-purpose control requirements utilising the individual advantages of several sensors and modelling techniques. The ISPC system is supposed to operate as a conceptual integration of sensors, process models and different control modules. Two prototype systems, based on five-axis machining centres, for real-time control of the machining process are outlined. Different strategies for monitoring and control are developed, implemented and experimentally tried out, and the studies conducted demonstrate results that encourage further research work devoted to verification of the proposed control concept.

    The results obtained in the initial experiments utilising methods for process control and monitoring, such as double exponential smoothing technique (DES), multivariate monitoring applied to signal tracking and artificial neural networks applied to cutting torque control, reveal that the different techniques have potential to improve the performance of monitoring and control tasks, thus contributing to the creation of more sophisticated and reliable solutions in the ISPC concept.

  • 3.
    Bäckström, Mikael
    Linköping University, IKP.
    Performance of Adaptive Control: Significant Features1991Licentiate thesis, monograph (Other academic)
  • 4.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Carlsson, Peter
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Danvind, Jonas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Koptioug, Andrei
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Sundström, David
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    A New Wind Tunnel Facility Dedicated to Sports Technology Research and Development2016In: Procedia Engineering, Elsevier, 2016, Vol. 147, p. 62-67Conference paper (Refereed)
    Abstract [en]

    It is desirable to test sportswear and sports equipment at exactly the same conditions experienced during use. Although outdoor tests are in many cases the most adequate, they are at the same time quite complex, demand special measurement technology and wearable equipment. Results of such tests are often hard to interpret due to large variations because of rapidly varying ambient conditions and individual specifics of human objects, among other factors, which are hard or impossible to control. One common alternative is provided through indoor tests made in a stable, controlled environment. Controlling such parameters as temperature, wind speed and direction, air humidity with indoor facilities intended to replicate ambient conditions, and designed to house large objects, is a complex undertaking. Furthermore, replicating seasonal conditions complicates matters even more. A significant amount of research and development related to the operation of sports and other related equipment at high speeds and windy conditions has been carried out in wind tunnels with different degrees of climatic realism. However, the majority of such facilities are designed and constructed for the automotive industry, the aerospace industry and for marine research. A new wind tunnel facility, opened in March 2015 at the Sports Tech Research Centre at Mid Sweden University, is currently among the very few facilities in the world designed under the direct control of sports technology specialists and dedicated primarily to research and development within sports, outdoor clothing and footwear as well as equipment development and testing. The main goal when constructing this dedicated facility has been to successfully replicate ambient conditions for training and equipment testing in environments with controlled wind speed, temperature (+4 to +35°C) and precipitation (from fine mist to heavy downfall). The wind tunnel facility houses the largest moving belt in Sweden (5 m long and 2.7 m wide) which can be adjusted for leveled, uphill and downhill motion. The moving belt is placed in a 10 m2 test section in which the wind speed can be adjusted to match belt speed or independently up to 55 km/h (without narrowing the test section). A fog and rain system, mounted in the test section, can generate rainy conditions varying from fine mist to heavy monsoon. It is also possible to open the facility in order to allow experiments to be performed in wide range of outdoor, ambient conditions. This paper presents the basic parameters of the new wind tunnel facility. As this facility is open for wider international cooperation, we also report the general directions of current research and the future work planned to be carried out at this facility.

  • 5.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Dahlén, Leon
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Ebrahimzadeh, Reza
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Taylor Made Titanium Insoles in Alpine Ski Boots2009In: Asia-Pasific Congress on Sports Technology, 2009Conference paper (Refereed)
  • 6.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Koptioug, Andrei
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    People and Skis2006In: Science-First Hand, ISSN 1810-8520, no 3, p. 110-125Article in journal (Other (popular science, discussion, etc.))
  • 7.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Koptyug, Andrey
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Automatic Pacenotes2013Patent (Other (popular science, discussion, etc.))
  • 8.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Kuzmin, Leonid
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Wiklund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Critical Factors Influencing Loss of Time after Shooting - A Case Study Performed During the 2008 IBU Biathlon World Championships2009In: The Impact of Technology on Sport III, 2009, p. 33-37Chapter in book (Other academic)
    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.

  • 9.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Kuzmin, Leonid
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Influencing factors on time-loss after shooting in Biathlon2011In: Moderns systems for application in Biathlon, Omck: Russian Sports Federation , 2011, p. 154-159Conference paper (Refereed)
  • 10.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Koptyug, Andrey
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Carlsson, Peter
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Danvind, Jonas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Wiklund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Sports Technology Education at Mid Sweden University2013In: 6TH ASIA-PACIFIC CONGRESS ON SPORTS TECHNOLOGY (APCST), Elsevier, 2013, Vol. 60, p. 214-219Conference paper (Refereed)
    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.

  • 11. Bäckström, Mikael
    et al.
    Wiklund, Håkan
    A step towards integrated supervisory control of complex machining processes1998In: Changing the ways we work : shaping the ICT-solutions for the next century : proceedings of the Conference on Integration in Manufacturing, Göteborg, Sweden, 6-8 October 1998, Amsterdam: IOS press , 1998, p. 817-Conference paper (Refereed)
  • 12. Bäckström, Mikael
    et al.
    Wiklund, Håkan
    An approach to integrated process monitoring and quality control of advanced machining1999In: Life cycle approaches to production systems : management, control, and supervision; preprints; ASI '99; Advanced Summer Institute '99, ICIMS-NOE; September 22 - 24, 1999, Leuven, Belgium, Leuven, Belgien, 1999, p. 150-Conference paper (Refereed)
  • 13. Bäckström, Mikael
    et al.
    Wiklund, Håkan
    Deployment of quality and productivity requirements in integrated process control1999In: Proceedings of The 26th International Conference on Computers & Industrial Engineering, December 15-17, 1999, Melbourne, Australia, 1999, p. 70-74Conference paper (Other academic)
  • 14.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Wiklund, Håkan
    Development of a multi-tooth approach to tool condition monitoring in milling1998In: Insight (Northampton), ISSN 1354-2575, E-ISSN 1754-4904, Vol. 40, no 8, p. 548-552Article in journal (Refereed)
  • 15.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Wiklund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Integration of real-time quality control and process monitoringManuscript (preprint) (Refereed)
  • 16.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Wiklund, Håkan
    Integration of real-time quality control and process monitoring2000In: The 33rd CIRP International Seminar on Manufacturing Systems : the manufacturing systems in its human context : a tool to extend the global welfare : 5-7 June, 2000, Stockholm, Sweden : proceedings.: CIRP International Seminar on Manufacturing Systems (33 : 2000 : Stockholm), Sth.: KTH, Inst.för farkost och flyg , 2000, p. 438-Conference paper (Refereed)
  • 17.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Wiklund, Håkan
    On the application of quality function deployment in integrated supervisory process control2000In: IMechE conference transactions, 2000, Vol. 2000, no 5, p. 531-540Conference paper (Refereed)
  • 18.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Wiklund, Håkan
    On the use of neural networks and statistical methods in the integrated supervisory process control concept1999Report (Other academic)
  • 19.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Wiklund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    QFD as a tool to improve quality control in a complex manufacturing environment2004In: The Asian Journal on Quality, ISSN 1598-2688, Vol. 5, no 1, p. 10-22Article in journal (Refereed)
  • 20.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Wiklund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    QFD as a Tool to Improve Quality Control in a Complex Manufacturing Environment2003In: Proceedings of The Sixth Quality Management and Organisational Development Conference (QMOD 2003) Paris, France 1-3 october 2003 - Paris, 2003Conference paper (Other academic)
  • 21.
    Bäckstöm, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Dahlen, Leon
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Essential ski characteristics for cross-country skis performance2008In: ENGINEERING OF SPORT 7, VOL 2, Paris: Springer, 2008, p. 543-549Conference paper (Refereed)
    Abstract [en]

    Winner or trail hog? Much depends on the ski characteristics. The manufacturing of skis is a complicated process involving several materials and different process steps. This gives as a result that every ski obtains unique characteristics such as span curve and bending stiffness etc. For high performance skiers as the member of the Swedish ski team the importance of equal characteristics of each ski in a pair is vital. The process of matching skis to a pair is the process of finding two individual skis with the most similar characteristics. This is traditionally done by hand with simpler equipment. Our measurement system is developed for faster and more accurate ski characteristics assessment. The characteristics do impose the overall performance of the ski. It produces the span curve with very high accuracy and gives a good representation of the pressure distribution over the full length of the ski. The measured characteristics could, in our opinion, also be used in selecting skis for different weather and track conditions. The ski measurement system has been used by the Swedish cross-country team during the last 2,5 years which have resulted in a faster and more accurate matching of skis. In collaboration with the Swedish ski team have also an investigation concerning correlation between ski characteristics and weather and track conditions has been initiated with some preliminary results already obtained.

  • 22. Cai, D. Q.
    et al.
    Xie, M
    Goh, T. N.
    Wiklund, Håkan
    Bäckström, Mikael
    A study of control chart for adjusted processes1999In: The 26th International Conference on Computers & Industrial Engineering (the 26th C & IE) : December 15-17, 1999, Melbourne, Australia, 1999, p. 443-447Conference paper (Refereed)
  • 23.
    Carlsson, Peter
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Ainegren, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Sundström, David
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Esping, Björn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Koptioug, Andrey
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Cross-Country Ski2015In: The Engineering Approach to Winter Sports / [ed] Braghin F., Cheli F., Maldifassi S., Melzi S. and Sabbioni E., Springer, 2015, p. 107-152Chapter in book (Other academic)
    Abstract [en]

    Cross-country skiing, biathlon and ski orienteering are competitive sports with practitioners who are mostly from countries in the northern hemisphere. The competition season is during the time when the ground is covered with snow, which roughly extends from mid-November to late March. During the rest time of the year, which is a long preparatory period of training for the skiers before the competition season, the skiers use roller skis for dryland training with the aim of imitating skiing on snow. Furthermore, over the last few decades, fairly specific indoor testing methods for cross-country skiers have become possible due to the development of treadmills that allow roller skiing using classical and freestyle techniques.

  • 24.
    Cronskär, Marie
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Modeling of fractured clavicles and reconstruction plates using CAD, finite element analysis and real musculoskeletal forces input2013In: WIT Transactions on Biomedicine and Health, WIT Press, 2013, p. 235-243Conference paper (Refereed)
    Abstract [en]

    This study focuses on the treatment options for clavicle fractures, more specifically the cases with a need for internal fixation: non-unions and some complex fractures. Enhancing the understanding of the loading of the bone and fixation device enables treatment options to be improved. The aim of the study was to develop a method for the realistic simulation of stresses and displacements in the bone and fixation device and to use this method to make comparisons between a conventional reconstruction plate and a customized plate, designed from patient-specific computed tomography (CT) data. In an earlier study, a finite element (FE) mesh of the clavicle geometry was created from CT data, subjected to muscle forces and other boundary conditions from a multibody musculoskeletal model and imported into the FE solver. In this study, a solid 3D model of the same clavicle geometry was created and the mesh was replaced by the solid model to make the FE-model more suitable for the comparison of different plates. An LCP Reco-Plate 3.5 straight, 6 holes (by Synthes) was compared with a customized plate which was designed to follow the anatomy of the bone. The LCP-Reco plate has tapered reconstruction segments throughout the plate to allow for the plate reshaping during surgery. The customized plate was designed without such segments and with a lower width than the LCP plate. The two different plates showed stresses and displacements of similar magnitudes. The customized plate had a more even stress distribution while the LCP plate had higher stress concentrations in the middle of the plate and on the edges of the tapered reconstruction segments. To the authors' best knowledge, this is the first FE model of a clavicle bone with plate and it may, upon further development, serve as a useful instrument for improved clavicle fixation.

  • 25.
    Cronskär, Marie
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Implementation of digital design and solid free-form fabrication for customization of implants in trauma orthopaedics2012In: Journal of medical and biological engineering, ISSN 1609-0985, Vol. 32, no 2, p. 91-96Article in journal (Refereed)
    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.

  • 26.
    Cronskär, Marie
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Production of Customized Hip Stem Prostheses: a Comparison Between Machining and Additive Manufacturing2013In: Rapid prototyping journal, ISSN 1355-2546, E-ISSN 1758-7670, Vol. 19, no 5, p. 365-372Article in journal (Refereed)
    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.

  • 27.
    Cronskär, Marie
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Koptioug, Andrei
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Application of electron beam melting to titanium hip stem Implants2008In: / [ed] Katalinic, B., Vienna: DAAAM International Vienna , 2008, p. 1559-1560Conference paper (Refereed)
    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.

  • 28.
    Cronskär, Marie
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Nilsson, K-G
    Samuelsson, B
    Patient-specific bone plates for clavicle fractures: Design, manufacturing and strength analysisManuscript (preprint) (Other academic)
  • 29.
    Cronskär, Marie
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    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 Manufacturing2015In: Journal of mechanical design (1990), ISSN 1050-0472, E-ISSN 1528-9001, Vol. 137, no 11, article id 111418Article in journal (Refereed)
    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.

  • 30.
    Ek, Rebecca
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Carlsson, Peter
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    The Effect of EBM Process Parameters upon Surface Roughness2016In: Rapid prototyping journal, ISSN 1355-2546, E-ISSN 1758-7670, Vol. 22, no 3, p. 495-503Article in journal (Refereed)
    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.

  • 31.
    Geldart, Martin
    et al.
    University of Nottigham.
    Webb, Phil
    University of Nottigham.
    Larsson, Hans
    Luleå University of Technology, Department of Physics and Mechanical Engineering.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Gindy, Noel
    University of Nottigham.
    Rask, Kjell
    Luleå University of Technology, Department of Physics and Mechanical Engineering.
    A direct comparison of the machining performance of a variax 5 axis parallel kinetic machining centre with conventional 3 and 5 axis machine tools.2003In: International journal of machine tools & manufacture, ISSN 0890-6955, E-ISSN 1879-2170, Vol. 43, no 11, p. 1107-1116Article in journal (Refereed)
    Abstract [en]

    The current trend within the Tool and Die manufacturing sector is to machine components directly from hardened material using high speed 5-axis machining. This has been driven by the increasing requirements for cost competitiveness and lead-time reduction. Significant research effort has been applied to the optimisation of the process with factors such as tooling and machining strategies being considerably improved. However, the underlying structures of the machine tools used have remained unchanged and still consist of a serial kinematic chain. One of the standard justifications for the development of machines designed around parallel kinematic chains is that they should exhibit inherently greater stiffness, have higher axis accelerations and be capable of generating significantly higher cutting forces than conventional serial machines. This suggests that they should be ideally suited to the direct manufacture of tools and dies from hardened material. The comparison of different machine tool types is a complex and difficult process, particularly when their structures are fundamentally different. This paper describes an approach used to compare the performance of three very different types of machines. The technique uses two parameters; surface finish and geometric accuracy to assess the relative performance of different machine tools when cutting hardened material. The method is used to compare a serial kinematic 5-axis machining centre, a serial kinematic 3-axis machining centre and a parallel kinematic 6-axis machining centre. The results of the comparison are presented in this paper wand show that all the machine tools performed to an equal standard for materials with a hardness of 54HRc but for very hard materials, 62HRc, the parallel kinematic machine out performed the serial machine tools.

  • 32.
    Johansson, Jon
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Collaboration - a Key Factor for the Application of Discrete Event Simulation in Real World Manufacturing Industry2007Conference paper (Refereed)
    Abstract [en]

    In manufacturing industry, the application of Discrete Event Simulation (simulation) has not come to a breakthrough in all industrial sectors. Simulation technology in itself may appear abstract, and without internal competence or earlier experience the step to hire a simulation consultant is not obvious in all industries. This presentation provides a multifaceted perspective of the application of simulation in industry. The frame of reference found in methods for the analysis of the collaborative engineeringdesign process provides an inspiring and supporting perspective and gives an insight into the present state of simulation application for future improvement of simulation projects by mutual references.

  • 33.
    Klingvall Ek, Rebecca
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Fatigue properties of electrochemical polished and hot isostatic pressed Ti6A14V manufactured by electron beam meltingIn: Article in journal (Refereed)
  • 34.
    Klingvall Ek, Rebecca
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Fatigue properties of Ti-6Al-4V manufactured using electron beam melting2017In: Proceedings Euro PM 2017: International Powder Metallurgy Congress and Exhibition 2017, Brussels: EPMA European Powder Metallurgy Association , 2017Conference paper (Refereed)
    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.

  • 35.
    Klingvall Ek, Rebecca
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Influence of the surface topography of additive manufactured Ti6A14V on fatigue and calculations of the stress concentration factorIn: Article in journal (Refereed)
  • 36.
    Klingvall Ek, Rebecca
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Hong, Jaan
    Uppsala University, Uppsala.
    Thor, Andreas
    Uppsala University, Uppsala.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Micro- to Macroroughness of Additively Manufactured Titanium Implants in Terms of Coagulation and Contact Activation2017In: International Journal of Oral & Maxillofacial Implants, ISSN 0882-2786, E-ISSN 1942-4434, Vol. 32, no 3, p. 565-574Article in journal (Refereed)
    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.

  • 37.
    Koptioug, Andrei
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Ainegren, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Nilsson, Kajsa
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Studying Moisture Transport Trough "Active" Fabrics Using Humidity-Temperature Sensor Nodes2018In: Proceedings, Volume 2, ISEA 2018: / [ed] Dr Hugo Espinosa, David R. Rowlands, Jonathan Shepherd, Professor David Thiel, 2018, Vol. 2, p. 230-, article id 6Conference paper (Refereed)
    Abstract [en]

    Active fabrics providing better comfort of the garments and footwear rapidly become an essential part of our life. However, only limited information about the performance of such fabrics is commonly available for the garment and footwear designers, and tests are often done only with the final products. Thus development of the objective testing methods for the fabric assemblies containing microporous membranes and garments using them is one of the important topics. Garment tests in the climate chamber when exercising in windy and rainy conditions with a set of temperature and humidity sensors placed over the body allow comparing manufactured garments for thermal and humidity comfort. To allow for better material testing a new laboratory setup was developed for studying the dynamics of the humidity transport through different fabrics at realistic conditions in extension of the existing ISO test procedure. Present paper discusses the experimental procedures and first results acquired with new setup.

  • 38.
    Koptioug, Andrei
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Botero Vega, Carlos Alberto
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Popov, Vladimir
    Israel Institute of Metals, Technion R&D Foundation, Technion City, 3200003, Haifa, Israel.
    Chudinova, Ekaterina
    Tomsk Polytechnic University, Tomsk, Russia.
    Developing new materials for Electron Beam Melting: experiences and challenges2018Conference paper (Refereed)
    Abstract [en]

    Lack of industrially available materials for additive manufacturing (AM) of metallic materials along with the promises of materials with improved or unique properties provides a strong drive for developing new process/material combinations. As powder bed technologies for metallic materials are relatively new to the market, and to some extent are only maturing, developers of new process/material combinations have certain challenges to overcome. Firstly, basic knowledge on the behavior of materials (even those well established for other applications) under extreme conditions of melting/solidification with beam-based AM methods is far from being adequate. Secondly, manufacturing of the equipment is up to date driven by industrial application, thus optimization of the AM machines for small test batches of powders is still belongs to research and development projects. Also, majority of the powder manufacturers are primarily driven by the market development, and even they are well aware of the demands imposed by the powder bed AM machines, availability of small test batches of adequate powders may be problematic or at least quite costly for the R&D oriented users. Present paper describes the experiences in developing new materials for EBM A2 machine by Arcam EBM, modified for operating with powder batches of 100-200 ml and less. In particular it discusses achievements and challenges of working with powders from different materials with specifications far beyond the range suggested by machine manufacturer. Also it discusses the possibility of using blended rather than pre-alloyed powders for achieving both composite-like and alloyed materials in the same part by steering electron beam energy deposition strategy.

  • 39.
    Koptioug, Andrei
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    3D-printing: a future “magic wand” for global manufacturing. How can we benefit from it today for sports and health care?2017In: Proceedings of the 5th International Congress on Sport Sciences Research and Technology Support, icSPORTS / [ed] Jan Cabri, Pedro Pezarat Correia, INSTICC Press, 2017Conference paper (Refereed)
    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.

  • 40.
    Koptioug, Andrei
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Botero Vega, Carlos Alberto
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    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 powders2018In: Euro PM2018 Proceedings, European Powder Metallurgy Association, EPMA , 2018Conference paper (Refereed)
    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.  

  • 41.
    Koptyug, Andrey
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Ainegren, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Schieber, Erika
    Persson, Jonas
    Possibility of modern humidity sensor application in the studies ofmoisture transport through the sports and outdoor garments2016In: icSPORTS 2016 - Proceedings of the 4th International Congress on Sport Sciences Research and Technology Support, Portugal: SciTePress, 2016, p. 51-58Conference paper (Refereed)
    Abstract [en]

    Sensor nodes containing pairs of temperature and humidity sensors were assessed as a mean of garmentperformance and comfort studies. Modern sensors are small, low weight and produce minimal disturbancewhen placed under the garments and in the footwear. Four sensor nodes were used to provide dynamicinformation about heat and humidity transfer properties of garments during the tests in realistic conditions.Pilot studies were carried out for the few models of cross country skiing garments and waders. Main studieswere carried out in the wind tunnel at Mid Sweden University having pivoted treadmill, temperature controland rain capacity. Additional experiments with the waders were carried out in a large water tank. Studies ofthe temperature and humidity dynamics under the garments containing microporous membranes illustratethe importance of recognizing main features of such materials. In particular, such membranes can onlytransport moisture from the side where humidity is higher. It means that garments and footwear containingsuch membranes will potentially behave differently when ambient air humidity changes. In particular,modern garments with incorporated microporous membranes being superior at low ambient air humidity canbe dramatically less effective for moisture transfer from the body in the rain.

  • 42.
    Koptyug, Andrey
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Tin Man- Making Spare Parts for Human Body2012In: Science First Hand, ISSN 1810-3960, Vol. 44, no 2, p. 45-57Article in journal (Other (popular science, discussion, etc.))
    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.

  • 43.
    Koptyug, Andrey
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Cross-country Ski Vibrations: Loaded Vs Unloaded Skis2012Conference paper (Other academic)
  • 44.
    Koptyug, Andrey
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Gliding-induced ski vibrations: Approaching proper modeling2014In: Procedia Engineering, 2014, Vol. 72, p. 539-544Conference paper (Refereed)
    Abstract [en]

    Phenomena of the ski and snow boards vibrations generated in gliding are known for years. In the cross country and jumping skis such vibrations are not very obvious but can play quite positive role reducing the effective gliding friction. The research into the nature of friction-induced vibrations and the factors influencing their frequencies and magnitudes is driven by the desire to control them for improving ski gliding performance. Significant amount of experimental data acquired in the field and laboratory studies is already available making it possible to formulate certain qualitative conclusions. But so far it did not bring comprehensive understanding of the phenomenon and specifically of the mechanisms controlling such vibrations. Modeling is one of the potent tools allowing to deeper understand experimentally studied phenomena and it can provide much stronger quantitative prediction capacity. Present paper discusses possible approaches to modeling of the phenomenon and first results of constructing simplified models. © 2014 The Authors.

  • 45.
    Koptyug, Andrey
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Laboratory Setup for the Cross Country Ski Vibrations Measurements: Methodology and First Results2012Conference paper (Refereed)
  • 46.
    Koptyug, Andrey
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Studies into the Mechanisms of the Cross-country Ski Vibrations and Possible Models of the Phenomenon2013In: 6TH ASIA-PACIFIC CONGRESS ON SPORTS TECHNOLOGY (APCST), Elsevier, 2013, Vol. 60, p. 40-45Conference paper (Refereed)
    Abstract [en]

    Field and laboratory measurements show a presence of intense cross-country ski vibrations during free gliding. Thereare indications that such vibrations may and indeed do affect the average friction forces and thus should affect the skigliding. Our studies into the nature of these vibrations and the factors influencing their frequencies and magnitudesare driven by the desire to control them for improving ski gliding performance. The complexity of the correspondingresonance system, represented by constant interaction of the skier, the skis and the snow, and the mechanisms of thevibration excitation, most probably dominated by the stochastic forces caused by a stick-slip character of the friction,demand new approaches to the modelling and experiments. Present paper describes some results of the experimentallaboratory studies of such vibrations, and possible approaches to their modelling following the routes suggested inmodelling of the similar phenomena.

  • 47.
    Koptyug, Andrey
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Carlsson, Peter
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Cross-country ski vibrations and possible mechanisms of their influence on the free gliding2012In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 34, p. 473-478Article in journal (Refereed)
    Abstract [en]

    Present paper describes the results of experimental studies on the self-induced and forced vibrations of loaded cross country skis and presents the discussion on the possible mechanisms causing such vibrations and the ways they can influence the friction between the ski running surface and the snow. Studied vibrations of gliding skis are most probably caused by the frictional effects. Mechanisms involved are similar to the ones causing the brake disc squeal or the violin string excitation by the bow. Major factors responsible for the development of these vibrations such as micro roughness of the surfaces, nonlinearities in the material properties, thermo-elastic instabilities and instabilities due to decreasing friction with increasing sliding velocity are also common for the case of gliding skis. The results of this study indicate that the ski vibration pattern both in amplitude and in frequency could influence the ski gliding properties. Though it seems quite feasible that the control of the cross country ski vibrations can improve the gliding performance, further systematic studies are needed to confirm it and to formulate the consecutive strategies of cross country ski design improvement.

  • 48.
    Koptyug, Andrey
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Backstrom, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Klingvall, Rebecca
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Electron Beam Melting: Moving from Macro- to Micro- and Nanoscale2012In: Materials Science Forum, Switzerland: Trans Tech Publications Inc., 2012, Vol. 706-709, p. 532-537Conference paper (Refereed)
    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.

  • 49.
    Koptyug, Andrey
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Multiscale surface structuring of the biomedical implants manufactured in Electron Beam Melting technology: Demands, advances and challengesArticle in journal (Refereed)
    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.

  • 50.
    Koptyug, Andrey
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    New Materials for Additive Manufacturing in Metal: Back to Basics?2017Conference paper (Refereed)
    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.

     

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