Background

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.

Publications

Articles in journals Chapters in books Conference papers Doctoral theses, comprehensive summaries

Articles in journals

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

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.

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.

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

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.

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.

Beste, U. , Koptyug, A. , Vikner, P. , Nilsson, M. , Rännar, L. & Bäckström, M. (). Energy consumption comparison in production of highly alloyed metallic components by conventional and additive manufacturing methods. Journal of Materials Processing Technology,

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

Ek, R. , Rännar, L. , Bäckström, M. & Carlsson, P. (). The Effect of EBM Process Parameters upon Surface Roughness. Rapid prototyping journal,

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

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. .

Koptyug, A. , Rännar, L. , Bäckström, M. & Cronskär, M. (2014). Additive manufacturing for medical and biomedical applications : Advances and challenges. In Advanced Materials Research.. pp. 1286--1291.

Skoglund, P. & Rännar, L. (2014). A survey on implementation of additive manufacturing to the manufacturing process of orthopedic and orthotic appliances. .

Rännar, L. & Hamberg, Å. (2014). Design and manufacture of a titanium tibial reinforcement cage using electron beam melting. .

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. .

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.

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. .

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. .

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. .

Ainegren, M. , Rännar, L. , Carlsson, P. & Tinnsten, M. (2012). The multi functional roller ski. .

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.

Petrovic, V. , Jordá, O. , Martin, A. , Rännar, L. R. & Dejanovic, S. (2011). Knowledge assisted Rapid Manufacturing, KARMA Project. .

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.

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. . Vienna :

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)