Lars-Erik Rännar

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Lars-Erik got his Ph.D. at the Norwegian University of Science and Technology (NTNU), Trondheim, Norway, with the thesis “On Optimization of Injection Molding Cooling” and since autumn 2014, Lars-Erik’s has a position as an Associate Professor at the Department of Quality Technology, Mechanical Engineering and Mathematics, Campus Östersund, Mid Sweden University.

Area of interest

Lars-Erik's speciality is additive manufacturing and he has more than 15 years of experience within the area. The first studies focused on how to implement what at that time was called rapid tooling into the injection molding industry. Later on, other projects were initiated where additive manufacturing was used as a tool to design and manufacture medical models, that is plastic models manufactured from the data retrieved from x-ray pictures. In 2007, the group acquired the first A2 system (Arcam AB, Mölndal, Sweden) world-wide and at that point, the research group within additive manufacturing was initiated and today Lars-Erik is the head of the research group.

Current research

His research is focused on additive manufacturing and with special focus on the Electron beam melting method (EBM, Arcam AB, Mölndal, Sweden). The method is used within several projects, ranging from sports technology, over to material/process development and medical applications. Together with researchers from from clinical institutions (e.g. Uppsala University, Skåne University Hospital, Östersund Hospital), methods for virtual planning and direct manufacturing of medical implants in biocompatible titanium have been developed in the areas of maxillofacial surgery and orthopedics.

The development of new materials for the EBM process is also an important part of the research. The aim is to develop new materials manufactured in the EBM process which will make it possible to design and manufacture new kind of products with unique characteristics. Today, Lars-Erik and his colleuages are one of a handful of groups world-wide which are certified to do this kind of development and examples of materials that has been developed are stainless steel, amorphous metal and high alloyed high speed steel.

The development of new products and functionalities within the area of Sports Engineering is also in focus for the research carried out by Lars-Erik. Some examples are pole tips for roller skiing on a tread mill and new types of insoles for alpine skiing facilitating optimal force distribution.

Today, Lars-Erik is involved in two national projects and one international project focusing on additive manufacturing.

Teaching and tutoring

Lars-Erik is a teacher in the areas of plastic manufacturing, additive manufacturing, 3D modeling, reversed engineering and computer aided design. He is responsible for numerous courses on both basic and advanced level and program coordinator for the bachelor programmes within engineering.

He is also participating as a lecturer ("Additive Manufacturing Technologies for Metals") in the graduate school hosted by the project "Produktion 2030", a strategic programme for production research and innovation i Sweden.

Other information

Lars-Erik is supervisor for the Ph.D. student Rebecca Klingvall. Rebecca's studies are focused on the biocompatibility of different surface topographies manufactured by EBM.


Articles in journals

Olsén, J. , Shen, Z. , Liu, L. , Koptyug, A. & Rännar, L. (2018). Micro- and macro-structural heterogeneities in 316L stainless steel prepared by electron-beam melting. Materials Characterization, vol. 141, pp. 1-7.  

Zhong, Y. , Rännar, L. , Liu, L. , Koptyug, A. , Wikman, S. , Olsen, J. , Cui, D. & Shen, Z. (2017). Additive manufacturing of 316L stainless steel by electron beam melting for nuclear fusion applications. Journal of Nuclear Materials, vol. 486, pp. 234-245.  

Zhong, Y. , Rännar, L. , Wikman, S. , Koptyug, A. , Liu, L. , Cui, D. & Shen, Z. (2017). Additive manufacturing of ITER first wall panel parts by two approaches : Selective laser melting and electron beam melting. Fusion engineering and design, vol. 116, pp. 24-33.  

Surmeneva, M. A. , Surmenev, R. , Chudinova, E. A. , Koptioug, A. , Tkachev, M. S. , Gorodzha, S. N. & Rännar, L. (2017). Fabrication of multiple-layered gradient cellular metal scaffold via electron beam melting for segmental bone reconstruction. Materials & design, vol. 133, pp. 195-204.  

Rännar, L. , Koptioug, A. , Olsén, J. , Saeidi, K. & Shen, Z. (2017). Hierarchical structures of stainless steel 316L manufactured by Electron Beam Melting. Additive Manufacturing, vol. 17, pp. 106-112.  

Klingvall Ek, R. , Hong, J. , Thor, A. , Bäckström, M. & Rännar, L. (2017). Micro- to Macroroughness of Additively Manufactured Titanium Implants in Terms of Coagulation and Contact Activation. International Journal of Oral & Maxillofacial Implants, vol. 32: 3, pp. 565-574.  

Thor, A. , Palmquist, A. , Hirsch, J. , Rännar, L. , Derand, P. & Omar, O. (2016). Clinical, Morphological, and Molecular Evaluations of Bone Regeneration With an Additive Manufactured Osteosynthesis Plate. The Journal of craniofacial surgery (Print), vol. 27: 7, pp. 1899-1904.  

Koptyug, A. , Rännar, L. , Bäckström, M. & Shen, Z. (2016). New Metallurgy of Additive Manufacturing in Metal : Experiences from the Material and Process Development with Electron Beam Melting Technology (EBM). Materials Science Forum, vol. 879, pp. 996-1001.  

Ek, R. , Rännar, L. , Bäckström, M. & Carlsson, P. (2016). The Effect of EBM Process Parameters upon Surface Roughness. Rapid prototyping journal, vol. 22: 3, pp. 495-503.  

Huo, J. , Derand, P. , Rännar, L. , Hirsch, J. & Gamstedt, E. K. (2015). Failure location prediction by finite element analysis for an additive manufactured mandible implant. Medical Engineering & Physics, vol. 37: 9, pp. 862-869.  

Cronskär, M. , Rännar, L. , Bäckström, M. , Nilsson, K. G. & Samuelsson, B. (2015). Patient-Specific Clavicle Reconstruction Using Digital Design and Additive Manufacturing. Journal of mechanical design (1990), vol. 137: 11  

Koptyug, A. , Rännar, L. , Bäckström, M. & Cronskär, M. (2014). Additive Manufacturing for Medical and Biomedical Applications: Advances and Challenges. Materials Science Forum, , pp. 1286-1291.

Koptyug, A. , Bergemann, C. , Lange, R. , Jaggi, V. , Rännar, L. & Nebe, J. B. (2014). Osteoblast Ingrowth into Titanium Scaffolds made by Electron Beam Melting. Materials Science Forum, vol. 783-786, pp. 1292-1297.  

Koptyug, A. , Rännar, L. , Bäckström, M. , Fager Franzén, S. & Dérand, P. (2013). Additive Manufacturing Technology Applications Targeting Practical Surgery. International Journal of Life Science and Medical Research, vol. 3: 1, pp. 15-24.    

Cronskär, M. , Rännar, L. & Bäckström, M. (2013). Production of Customized Hip Stem Prostheses : a Comparison Between Machining and Additive Manufacturing. Rapid prototyping journal, vol. 19: 5, pp. 365-372.  

Dérand, P. , Rännar, L. & Hirsch, J. (2012). Imaging, virtual planning, design and production of patient specific implants and clinical validation in cranio-maxillo-facial surgery. Cranial maxillofacial Trauma and Reconstruction, vol. 5: 3, pp. 137-144.  

Cronskär, M. , Rännar, L. & Bäckström, M. (2012). Implementation of digital design and solid free-form fabrication for customization of implants in trauma orthopaedics. Journal of medical and biological engineering, vol. 32: 2, pp. 91-96.  

Koptyug, A. , Bäckström, M. & Rännar, L. (2012). Tin Man- Making Spare Parts for Human Body. Science First Hand, vol. 44: 2, pp. 45-57.

Rännar, L. , Glad, A. & Gustafson, C. (2007). Efficient cooling with tool inserts manufactured by electron beam melting. Rapid prototyping journal, vol. 13: 3, pp. 128-135.  

Klingvall Ek, R. , Bäckström, M. & Rännar, L. (). Fatigue properties of electrochemical polished and hot isostatic pressed Ti6A14V manufactured by electron beam melting. ,

Klingvall Ek, R. , Bäckström, M. & Rännar, L. (). Influence of the surface topography of additive manufactured Ti6A14V on fatigue and calculations of the stress concentration factor. ,

Koptyug, A. , Rännar, L. & Bäckström, M. (). Multiscale surface structuring of the biomedical implants manufactured in Electron Beam Melting technology : Demands, advances and challenges. ,

Chapters in books

Ainegren, M. , Rännar, L. , Carlsson, P. & Tinnsten, M. (2013). The multifunctional roller ski. In Science and Nordic Skiing II. University of Salzburg, University of Jyväskylä. pp. 253-261.

Bäckström, M. , Kuzmin, L. , Rännar, L. & Wiklund, H. (2009). Critical Factors Influencing Loss of Time after Shooting - A Case Study Performed During the 2008 IBU Biathlon World Championships. In The Impact of Technology on Sport III.. pp. 33-37.

Conference papers

Botero, C. A. , Koptyug, A. , Jiménez-Piqué, E. & Rännar, L. (2018). Microstructure and nanomechanical behavior of modified 316L-based materials fabricated using EBM. Paper presented at the 2:nd International Conference on Electron Beam Additive Manufacturing, Nuremberg, Germany, April 11, 2018

Botero Vega, C. A. , Jiménez-Piqué, E. , Roos, S. , Skoglund, P. , Koptioug, A. , Rännar, L. & Bäckström, M. (2018). Nanoindentation: a suitable tool in metal Additive Manufacturing. Paper presented at the Materials Science & Technology, MS&T 2018, October 14-18, Columbus, USA

Skoglund, P. , Botero Vega, C. A. , Koptioug, A. , Rännar, L. & Bäckström, M. (2018). Possibility of the “cold start” of the build in Electron Beam Melting. Paper presented at the Materials Science & Technology, MS&T 2018, October 14-18, Columbus, USA

Olsén, J. , Koptioug, A. , Rännar, L. , Saedi, K. & Shen, Z. J. (2018). The Heterogenic Structure Formed During Electron Beam Melting of 316L Stainless Steel. Paper presented at the International Conference on Powder Metallurgy and Particulate Materials, (PowderMet), San Antonio, USA, June 17-20, 2018

Koptioug, A. , Rännar, L. , Botero Vega, C. A. , Bäckström, M. & Popov, V. (2018). Unique material compositions obtained by Electron beam melting of blended powders. In Euro PM2018 Proceedings.

Koptioug, A. , Bäckström, M. & Rännar, L. (2017). 3D-printing: a future “magic wand” for global manufacturing. How can we benefit from it today for sports and health care?. In Proceedings of the 5th International Congress on Sport Sciences Research and Technology Support, icSPORTS.

Mellin, P. , Magnusson, H. , Harlin, P. , Wikman, S. , Olsén, J. , Shen, Z. J. , Rännar, L. , Ålgårdh, J. & et al. (2017). Bonding EBM-built blocks of 316L steel, using hot isostatic pressing. In Proceedings Euro PM 2017 : International Powder Metallurgy Congress and Exhibition.

Roos, S. , Rännar, L. , Koptioug, A. & Danvind, J. (2017). Characterization of 316ln lattice structures fabricated via electron beam melting. In Materials Science and Technology Conference and Exhibition 2017, MS and T 2017.. pp. 336--343.  

Klingvall Ek, R. , Bäckström, M. & Rännar, L. (2017). Fatigue properties of Ti-6Al-4V manufactured using electron beam melting. In Proceedings Euro PM 2017: International Powder Metallurgy Congress and Exhibition 2017. Brussels :

Koptyug, A. , Rännar, L. & Bäckström, M. (2017). New Materials for Additive Manufacturing in Metal: Back to Basics?. Paper presented at the Frontiers in Materials Processing Applications, Research and Technology, FiMPART-2017, Bordeaux, France, July 9-12, 2017

Hirsch, J. , Dérand, P. , Gamstedt, K. , Huo, J. , Omar, O. , Palmquist, A. , Thor, A. , Nysjö, F. & et al. (2016). 3D printed titanium implants i Maxillofacial surgery. Paper presented at the 12th International Bernd-Spiessl Symposium, Basel, June 16-18, 2016

Leicht, A. , Vattur Sundaram, M. , Yao, Y. , Hrhya, E. , Nyborg, L. , Rännar, L. , Koptyug, A. , Frisk, K. & et al. (2016). As-HIP Microstructure of EBM Fabricated Shell Components. In Proceedings of Wolrd PM2016 - AM - Properties of Lightweight Materials ll.

Frisk, K. , Rännar, L. , Koptyug, A. , Petterson, N. , Persson, D. , Leicht, A. , Vattur Sundaram, M. , Hrhya, E. & et al. (2016). Characterisation Of EBM-built Shelled Samples of Ti6Al4V Compacted by HIP. Paper presented at the World Powder Metallurgy Congress, Hamburg, Germany, October 9-13, 2016

Leicht, A. , Shvab, R. , Hrhya, E. , Nyborg, L. & Rännar, L. (2016). Characterization of virgin and recycled 316L powder used in additive manufacturing. Paper presented at the 7th International Swedish Production Symposium, Lund, 25th - 27th of October, 2016

Cronskär, M. , Rännar, L. , Hamberg, Å. , Samuelsson, B. & Nilsson, K. G. (2016). Custom design and additive manufacturingof orthopedic implants and medical models in titanium and plastics. Paper presented at the Bernd-Spiessel Symposium, Basel, Switzerland, June 16-18, 2016

Cronskär, M. , Legrell, P. , Tidehag, P. & Rännar, L. (2016). Dental Implant Manufacturing using Electron Beam Melting – Geometry Deviation from Intraoral Scanning and from Cone Beam Computed Tomography. In EBAM 2016 : 1st International Conference on Electron Beam Additive Manufacturing.  

Cronskär, M. , Legrell, P. , Tidehag, P. & Rännar, L. (2016). Dental Implant Manufacturing using Electron Beam Melting – Geometry Deviation from Intraoral Scanning and from Cone Beam Computed Tomography. Paper presented at the Odontologisk riksstämma, Älvsjö, Sweden, 16-18 November, 2016

Rännar, L. , Koptyug, A. , Bäckström, M. & Jönsson, A. (2016). Water jet polishing of materials manufactured with electron beam melting technology. Paper presented at the World Powder Metallurgy Congress, Hamburg, Germany, 9-13 October, 2016

Wikman, S. , Shen, Z. , Rännar, L. , Obitz, C. & Öijerholm, J. (2015). Assessment of additive manufacturing of 316L(N)-IG for In-Vessel components and performance of CuCrZr at coolant water interfaces. Paper presented at the 17th International Conference on Fusion Reactor Materials (ICFRM-17), Aachen, Germany, 12-16 October, 2015.

Skoglund, P. & Rännar, L. (2014). A survey on implementation of additive manufacturing to the manufacturing process of orthopedic and orthotic appliances. Paper presented at the 5:th International Conference on Additive Technologies, Vienna, Austria, October 16-17 2014

Rännar, L. & Hamberg, Å. (2014). Design and manufacture of a titanium tibial reinforcement cage using electron beam melting. Paper presented at the 5:th International Conference on Additive Technologies, Vienna, Austria, 15. - 17. October 2014

Huo, J. , Hirsch, J. , Dérand, P. , Rännar, L. & Gamstedt, K. (2014). Finite element investigation of the in-vivo failure of a titanium alloy human jaw implant. Paper presented at the International Bernd-Spiessl-Symposium 2014 for Innovative and Visionary Technologies in Cranio-Maxillofacial Surgery, Basel, Switzerland, June 19-21 2014

Koptyug, A. , Rännar, L. , Bäckström, M. & Langlet, r. (2013). Bulk Metallic Glass Manufacturing Using Electron Beam Melting. In Proceedings from Additive Manufacturing & 3D Printing, Nottingham, UK, July 2013. Nottingham, UK :

Wikman, S. , Cui, D. , Shen, J. , Bin, Q. & Rännar, L. (2013). ON 3D ADDITIVE MANUFACTURING ITER COMPONENTS. Paper presented at the 16th International Conference On Fusion Reactor Materials; 20-26 October, 2013; Beijing, China

Bäckström, M. , Tinnsten, M. , Koptyug, A. , Rännar, L. , Carlsson, P. , Danvind, J. & Wiklund, H. (2013). Sports Technology Education at Mid Sweden University. In 6TH ASIA-PACIFIC CONGRESS ON SPORTS TECHNOLOGY (APCST). (Procedia Engineering). pp. 214--219.    

Hirsch, J. , Carlbom, I. , Dérand, P. , Nysjö, F. , Nyström, I. , Olsson, P. & Rännar, L. (2013). Virtual planning, additive manufacturing of biomaterials and real time reconstructive maxillofacial surgery. Paper presented at the 27:th International College for Maxillo-Facial-Surgery (ICMFS), Bad Hofgastein, Austria, March 4-9, 2013

Koptyug, A. , Rännar, L. , Backstrom, M. & Klingvall, R. (2012). Electron Beam Melting : Moving from Macro- to Micro- and Nanoscale. In Materials Science Forum. Switzerland : (Materials Science Forum). pp. 532--537.  

Ainegren, M. , Rännar, L. , Carlsson, P. & Tinnsten, M. (2012). The multi functional roller ski. Paper presented at the ICSNS 2012, 2nd International Congress on Science and Nordic Skiing, May 28th - 31st, Vuokatti, Finland

Hirsch, J. , Rännar, L. & Gamstedt, K. (2012). Virtual planning of reconstructions, production of individualized implants and transfer of the plan to the operating room in CMF surgery. Paper presented at the 26th Congress of the International College for Maxillo-Facial Surgery (ICMFS, Canary Islands, Spain

Bäckström, M. , Rännar, L. & Kuzmin, L. (2011). Influencing factors on time-loss after shooting in Biathlon. In Moderns systems for application in Biathlon. Omck : . pp. 154--159.

Petrovic, V. , Jordá, O. , Martin, A. , Rännar, L. R. & Dejanovic, S. (2011). Knowledge assisted Rapid Manufacturing, KARMA Project. Paper presented at the European Forum on Rapid Prototyping and Manufacturing (AEPR’11), Paris, France

Bäckström, M. , Dahlén, L. , Ebrahimzadeh, R. & Rännar, L. (2009). Taylor Made Titanium Insoles in Alpine Ski Boots. In Asia-Pasific Congress on Sports Technology.

Cronskär, M. , Rännar, L. , Bäckström, M. & Koptioug, A. (2008). Application of electron beam melting to titanium hip stem Implants. Paper presented at the International Conference on Additive Technologies

Israelsson, B. & Rännar, L. (2004). CAE and Rapid Prototyping Integrated in Product Marketing : A Novel Method for the Plastic Manufacturing Industry in the County of Jämtland. In Moldex3D European User’s Meeting, Billund, Denmark, September 2004..

Rännar, L. (2003). Efficient Cooling of FFF Injection Molding Tools with Conformal Cooling Channels, : An Introductory Analysis. In 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 : . pp. 433--437.

Holmberg, J. & Rännar, L. (2001). VerOpt - MATLAB Driven Versatile Optimization. In Program and proceedings for the Nordic MATLAB Conference Oslo, October 17-18, 2001. Trondheim : . pp. 207--212.

Doctoral theses, comprehensive summaries

Rännar, L. (2008). On Optimization of Injection Molding Cooling. Dis. (Comprehensive summary) Trondheim : , 2008 (Doctoral thesis at NTNU : 2008:113)