Integration of simulation driven DFAM and LCC analysis for decision making in l-PBF Patricia Nyamekye, Anna Unt, Antti Salminen, Heidi Piili Metals, 2020 Laser based powder bed fusion (L-PBF) is used to manufacture parts layer by layer with the energy of laser beam. The use of L-PBF for building functional parts originates from the design freedom, flexibility, customizability, and energy efficiency of products applied in dynamic application fields such as aerospace and automotive. There are challenges and drawbacks that need to be defined and overcome before its adaptation next to rivaling traditional manufacturing methods. Factors such as high cost of L-PBF machines, metal powder, post-preprocessing, and low productivity may deter its acceptance as a mainstream manufacturing technique. Understanding the key cost drivers of L-PBF that influence productivity throughout the whole lifespan of products will facilitate the decision-making process. Functional and operational decisions can yield profitability and increase competitiveness among advanced manufacturing sectors. Identifying the relationships between the phases of the life cycle of products influences cost-effectiveness. The aim of the study is to investigate the life cycle cost (LCC) and the impact of design to it in additive manufacturing (AM) with L-PBF. The article provides a review of simulation driven design for additive manufacturing (simulation driven DfAM) and LCC for metallic L-PBF processes and examines the state of the art to outline the merits, demerits, design rules, and life cycle models of L-PBF. Practical case studies of L-PBF are discussed and analysis of the interrelating factors of the different life phases are presented. This study shows that simulation driven DfAM in the design phase increases the productivity throughout the whole production and life span of L-PBF parts. The LCC model covers the whole holistic lifecycle engineering of products and offers guidelines for decision making.
Overview of optical digital measuring challenges and technologies in laser welded components in ev battery module design and manufacturing Heikki Saariluoma, Aki Piiroinen, Anna Unt, Jukka Hakanen, Tuomo Rautava, et al. Batteries, 2020 Ensuring the precision and repeatability of component assembly in the production of electric vehicle (EV) battery modules requires fast and accurate measuring methods. The durability of EV battery packs depends on the quality of welded connections, therefore exact positioning of the module components is critical for ensuring safety in exploitation. Laser welding is a non-contact process capable of welding dissimilar materials with high precision, for that reason it has become the preferred joining method in battery production. In high volume manufacturing, one of the main production challenges is reducing the time required for assessment of dimensional and geometrical accuracy prior to joining. This paper reviews the challenges of EV battery design and manufacturing and discusses commercially available scanner-based measurement systems suitable for fabrication of battery pack components. Versatility of novel metrological systems creates new opportunities for increasing the production speed, quality and safety of EV battery modules.
Application Development for the Evaluation of Penetration in Laser and Laser-Arc Hybrid Welding of Tee and Corner Joints Ilya Nikolaevich Udin, A.A. Voropaev, A. Unt Key Engineering Materials, 2019 Laser technologies deservedly take their place in modern mechanical engineering production. Using laser source for welding has already become common. However, the creation of critical welded constructions is impossible without extensive technological surveys, which can be greatly simplified by using a computational experiment. To achieve this goal, special programs are usually used. That can be unjustified difficult and thereby awkward for technological practice. The article describes an application built on the basis of a simplified model for calculating the temperature field for the cases of laser and laser-arc welding of internal fillet welds as well as single-sided T-joints and simultaneous double-sided welds. The results of calculations by the model and comparing them with experimental data have shown that it is sufficiently adequate for use in technological purposes. The developed application contemporaneously has a simple and intuitive interface, does not require significant computational resources and can be used for quick preliminary estimation of the result of welding for the selected type of weld.
Research of mechanical properties of cold resistant steel 09crni2mocu after direct laser deposition Y.A. Bistrova, E.A. Shirokina, R.V. Mendagaliev, M.O. Gushchina, A. Unt Key Engineering Materials, 2019 Review focuses on describing of mechanical properties of the components manufactured via direct laser depositionfrom cold resistant steel material. The results of tensile and impact testing are presented and microstructures of the fractures are shown. The process of laser deposition of cold-resistant steels, the formation of structures, as well as the mechanical properties of these samples are poorly understood. The results of tensile and impact tests are presented, and microstructures are shown. Mechanical tests for impact strength were carried out at a temperature of -40˚С, with different laser radiation powers. The results are given using the as-received powder, as well as used powder with a different mixing ratio, and the results are analyzed. As a result of the study, it was found that the fractional composition of the 09XH2MD alloy powder affects the mechanical characteristics of samples obtained by direct laser deposition. The effect of recycled powder on the mechanical properties of the obtained samples is given, the optimal laser deposition regimes are selected
High power fiber laserwelding of single sided T-joint on shipbuilding steel with different processing setups Anna Unt, Ilkka Poutiainen, Stefan Grünenwald, Mikhail Sokolov, Antti Salminen Applied Sciences Switzerland, 2017 Laser welding of thick plates in production environments is one of the main applications of high power lasers; however, the process has certain limitations. The small spot size of the focused beam produces welds with high depth-to-width aspect ratio but at times fails to provide sufficient reinforcement in certain applications because of poor gap bridging ability. The results of welding shipbuilding steel AH36 with thickness of 8 mm as a single-sided T-joint using a 10 kW fiber laser are presented and discussed in this research paper. Three optical setups with process fibers of 200 µm, 300 µm and 600 µm core diameters were used to study the possibilities and limitations set by the beam delivery system. The main parameters studied were beam inclination angle, beam offset from the joint plane and focal point position. Full penetration joints were produced and the geometry of the welds was examined. It was found that process fibers with smaller core diameter produce deeper penetration but suffer from sensitivity to beam positioning deviation. Larger fibers are less sensitive and produce wider welds but have, in turn, lower penetration at equivalent power levels.
Effect of optical parameters on fiber laser welding of ultrahigh strength steels and weld mechanical properties at subzero temperatures Antti Salminen, Farhang Farrokhi, Anna Unt, Ilkka Poutiainen Journal of Laser Applications, 2016 The recently developed direct-quenched ultrahigh strength steels have a combination of high tensile strength and toughness properties at subzero temperatures down to −80 °C. The low carbon content of the material is beneficial for weldability. Modern high power lasers provide an excellent opportunity to modify the focal point diameter by changing the feeding fiber diameter, collimation and focal length, and thus modify the beam intensity and heat input in actual welding process. In this study, butt joints of Optim 960 QC direct-quenched ultrahigh strength steel with a thickness of 8 mm were welded with 10 kW fiber laser with various different optical setups in order to evaluate the characteristics of the joints within the range of low to high heat inputs possible for this welding process. The mechanical properties of the joints were studied by subjecting the specimens to a number of destructive tests of mechanical properties. The weld metal hardness and tensile strength was tested. It was found that high quality butt joints with superior tensile strength could be obtained. However, having a high level of all these properties in the joint narrows, the process parameters' window and the heat input needs to be strictly controlled.
Laser scribing of stainless steel with and without work media Anna Unt, Heidi Piili, Marika Hirvimäki, Matti Manninen, Antti Salminen 29th International Congress on Applications of Lasers and Electro Optics Icaleo 2010 Congress Proceedings, 2010
Conceptual design proposal for the EU-DEMO electron cyclotron ex-vessel waveguide system with enhanced remote maintainability D Birlan, G Benzoni, W Brace, A Bruschi, A Cammi, R Chavan, F Crisinel, ... Fusion Engineering and Design 219, 115267 , 2025 2025
Metal additive manufacturing for industrial applications S Afkhami, M Amraei, A Unt, H Piili, T Björk LUT University , 2021 2021 Citations: 4
Overview of optical digital measuring challenges and technologies in laser welded components in EV battery module design and manufacturing H Saariluoma, A Piiroinen, A Unt, J Hakanen, T Rautava, A Salminen Batteries 6 (3), 47 , 2020 2020 Citations: 72
Integration of simulation driven DfAM and LCC analysis for decision making in L-PBF P Nyamekye, A Unt, A Salminen, H Piili Metals 10 (9), 1179 , 2020 2020 Citations: 14
The influence of a protective environment during direct laser deposition on the formation of structure and properties of steel F690W (09CrNi2MoCu) RV Mendagaliyev, AA Voropaev, OG Klimova-Korsmik, NV Lebedeva, ... Materials Today: Proceedings 30, 712-717 , 2020 2020 Citations: 3
Аpplication Development for the Evaluation of Penetration in Laser and Laser-Arc Hybrid Welding of Tee and Corner Joints IN Udin, AA Voropaev, A Unt Key Engineering Materials 822, 381-388 , 2019 2019 Citations: 3
Research of mechanical properties of cold resistant steel 09CrNi2MoCu after direct laser deposition YA Bistrova, EA Shirokina, RV Mendagaliev, MO Gushchina, A Unt Key Engineering Materials 822, 418-424 , 2019 2019 Citations: 5
Fiber laser and hybrid welding of T-joint in structural steels A Unt Lappeenranta University of Technology , 2018 2018 Citations: 1
Investigating the effect of beam parameters on joint formation in laser beam welding of T-joint in structural steel A Unt, S Grünenwald, I Poutiainen, A Salminen International Congress on Applications of Lasers & Electro-Optics 2018 (1), 704 , 2018 2018
Investigation of the influence of welding parameters on the weld geometry when welding structural steel with oscillated high-power laser beam S Grünenwald, A Unt, A Salminen Procedia CIRP 74, 461-465 , 2018 2018 Citations: 23
High power fiber laser welding of single sided T-joint on shipbuilding steel with different processing setups A Unt, I Poutiainen, S Grünenwald, M Sokolov, A Salminen Applied Sciences 7 (12), 1276 , 2017 2017 Citations: 28
Fiber laser-MIG hybrid welding of 5 mm 5083 aluminum alloy I Bunaziv, OM Akselsen, A Salminen, A Unt Journal of Materials Processing Technology 233, 107-114 , 2016 2016 Citations: 167
Effect of optical parameters on fiber laser welding of ultrahigh strength steels and weld mechanical properties at subzero temperatures A Salminen, F Farrokhi, A Unt, I Poutiainen Journal of Laser Applications 28 (2) , 2016 2016 Citations: 16
Thick section laser beam welding of shipbuilding steels: fiber and optical parameters optimization and gap bridgeability M Sokolov, A Salminen, I Borshchov, A Unt Procedia CIRP 83 , 2016 2016 Citations: 2
Effect of welding parameters and the heat input on weld bead profile of laser welded T-joint in structural steel A Unt, A Salminen Journal of laser applications 27 (S2) , 2015 2015 Citations: 47
Influence of filler wire feed rate in laser-arc hybrid welding of T-butt joint in shipbuilding steel with different optical setups A Unt, I Poutiainen, A Salminen Physics Procedia 78, 45-52 , 2015 2015 Citations: 27
Effects of sealing run welding with defocused laser beam on the quality of T-joint fillet weld A Unt, I Poutiainen, A Salminen Physics Procedia 56, 497-506 , 2014 2014 Citations: 9
Laser welding with high power laser: The effect of joint configuration E Lappalainen, A Unt, M Sokolov, M Vänskä, A Salminen Proceedings of the 14th NOLAMP Conference: The 14th Nordic Laser Materials … , 2013 2013 Citations: 4
Comparison of welding processes in welding of fillet Joints A Unt, E Lappalainen, A Salminen ISOPE International Ocean and Polar Engineering Conference, ISOPE-I-13-644 , 2013 2013 Citations: 5
Autogeneous laser and hybrid laser arc welding of T-joint low alloy steel with fiber laser systems A Unt, E Lappalainen, A Salminen Physics Procedia 41, 140-143 , 2013 2013 Citations: 19
MOST CITED SCHOLAR PUBLICATIONS
Fiber laser-MIG hybrid welding of 5 mm 5083 aluminum alloy I Bunaziv, OM Akselsen, A Salminen, A Unt Journal of Materials Processing Technology 233, 107-114 , 2016 2016 Citations: 167
Overview of optical digital measuring challenges and technologies in laser welded components in EV battery module design and manufacturing H Saariluoma, A Piiroinen, A Unt, J Hakanen, T Rautava, A Salminen Batteries 6 (3), 47 , 2020 2020 Citations: 72
Effect of welding parameters and the heat input on weld bead profile of laser welded T-joint in structural steel A Unt, A Salminen Journal of laser applications 27 (S2) , 2015 2015 Citations: 47
High power fiber laser welding of single sided T-joint on shipbuilding steel with different processing setups A Unt, I Poutiainen, S Grünenwald, M Sokolov, A Salminen Applied Sciences 7 (12), 1276 , 2017 2017 Citations: 28
Influence of filler wire feed rate in laser-arc hybrid welding of T-butt joint in shipbuilding steel with different optical setups A Unt, I Poutiainen, A Salminen Physics Procedia 78, 45-52 , 2015 2015 Citations: 27
Investigation of the influence of welding parameters on the weld geometry when welding structural steel with oscillated high-power laser beam S Grünenwald, A Unt, A Salminen Procedia CIRP 74, 461-465 , 2018 2018 Citations: 23
Autogeneous laser and hybrid laser arc welding of T-joint low alloy steel with fiber laser systems A Unt, E Lappalainen, A Salminen Physics Procedia 41, 140-143 , 2013 2013 Citations: 19
Effect of optical parameters on fiber laser welding of ultrahigh strength steels and weld mechanical properties at subzero temperatures A Salminen, F Farrokhi, A Unt, I Poutiainen Journal of Laser Applications 28 (2) , 2016 2016 Citations: 16
Integration of simulation driven DfAM and LCC analysis for decision making in L-PBF P Nyamekye, A Unt, A Salminen, H Piili Metals 10 (9), 1179 , 2020 2020 Citations: 14
Laser scribing of stainless steel with and without work media A Unt, H Piili, M Hirvimäki, M Manninen, A Salminen International Congress on Applications of Lasers & Electro-Optics 2010 (1 … , 2010 2010 Citations: 12
Effects of sealing run welding with defocused laser beam on the quality of T-joint fillet weld A Unt, I Poutiainen, A Salminen Physics Procedia 56, 497-506 , 2014 2014 Citations: 9
Research of mechanical properties of cold resistant steel 09CrNi2MoCu after direct laser deposition YA Bistrova, EA Shirokina, RV Mendagaliev, MO Gushchina, A Unt Key Engineering Materials 822, 418-424 , 2019 2019 Citations: 5
Comparison of welding processes in welding of fillet Joints A Unt, E Lappalainen, A Salminen ISOPE International Ocean and Polar Engineering Conference, ISOPE-I-13-644 , 2013 2013 Citations: 5
Effect of gas shielding and heat input on autogenous welding of duplex stainless steel A Salminen, E Westin, E Lappalainen, A Unt International Congress on Applications of Lasers & Electro-Optics 2012 (1 … , 2012 2012 Citations: 5
Metal additive manufacturing for industrial applications S Afkhami, M Amraei, A Unt, H Piili, T Björk LUT University , 2021 2021 Citations: 4
Laser welding with high power laser: The effect of joint configuration E Lappalainen, A Unt, M Sokolov, M Vänskä, A Salminen Proceedings of the 14th NOLAMP Conference: The 14th Nordic Laser Materials … , 2013 2013 Citations: 4
The influence of a protective environment during direct laser deposition on the formation of structure and properties of steel F690W (09CrNi2MoCu) RV Mendagaliyev, AA Voropaev, OG Klimova-Korsmik, NV Lebedeva, ... Materials Today: Proceedings 30, 712-717 , 2020 2020 Citations: 3
Аpplication Development for the Evaluation of Penetration in Laser and Laser-Arc Hybrid Welding of Tee and Corner Joints IN Udin, AA Voropaev, A Unt Key Engineering Materials 822, 381-388 , 2019 2019 Citations: 3
Thick section laser beam welding of shipbuilding steels: fiber and optical parameters optimization and gap bridgeability M Sokolov, A Salminen, I Borshchov, A Unt Procedia CIRP 83 , 2016 2016 Citations: 2
Fiber laser and hybrid welding of T-joint in structural steels A Unt Lappeenranta University of Technology , 2018 2018 Citations: 1
