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 2010, Lars-Erik’s has a position as an Assistant professor at the Department of Quality Technology, Mechanical Engineering and Mathematics, Campus Östersund, Mid Sweden University.

Area of interest

In July 2010, a framework 7 (FP7) project will start where Lars-Erik will be responsible for Mid Sweden University’s part in a project called KARMA – Knowledge based process planning and design for additive layer manufacturing - that will comprise 7 countries, 13 members and a total budget of 3.5 million Euros. The members will develop a planning tool for SMEs and the tool will automatic analysis and optimization of build-up direction searching for the best impact on processing parameters such as surface quality, build-up time and support structure. (www.karmaproject.eu)

Current research

His research is focused on additive manufacturing (rapid prototyping, free form fabrication etc) and with special focus on the Electron beam melting method (EBM, Arcam AB, Mölndal, Sweden). The method is used within several projects where the medical applications have got the most attention. For example, together with researchers from Uppsala University and Mälar hospital, a method for virtual planning and direct manufacturing of medical implants in biocompatible titanium have been developed in the area of maxillofacial surgery.

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 collaborates with two companies within this area.

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.

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.

Other information

Lars-Erik is assistant supervisor for two Ph.D. students at the department, Marie Cronskär and Rebecca Klingvall. Marie’s work is focused on the design of additive manufactured implants while Rebecca studies 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

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

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.

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. (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.

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.

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. ,

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

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.

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. .

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

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. .

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

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. .

Koptyug, A. , Rännar, L. & Backstrom, M. (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)