TY - CONF A1 - Rethmeier, Michael A1 - Gook, Sergej A1 - Biegler, Max A1 - Gumenyuk, Andrey T1 - Anwendung einer Kombination aus Laserhybrid- und Unterpulverschweißen zum Fügen dicker Bleche aus Schiffbaustahl EH36 N2 - In diesem Beitrag wird ein Schweißverfahren vorgestellt, mit dem 30 mm dicke Bleche aus Schiffbaustahl EH36 effizient und werkstoffgerecht gefügt werden können. Die wirtschaftlichen Vorteile des Verfahrens ergeben sich aus dem Wegfall der aufwendigen Kantenvorbereitung und der Reduzierung des Schweißzusatzbedarfs. Die Stumpfschweißnähte werden in einer Lagen-/Gegenlage-Technik durch Laserhybridschweißen und Unterpulverschweißen ausgeführt. Dabei erfolgt die Laserhybridschweißung als Einschweißung mit einer Tiefe von etwa 25 mm, während die Unterpulvernaht als zweiter Durchgang auf der gegenüberliegenden Seite des Bauteils mit einer Einschweißtiefe von 8 mm aufgebracht wird. Die Überlappung der beiden Lagen gewährleistet einen geschlossenen Nahtquerschnitt. Dank der partiellen Durchschweißung der Laserhybridnaht entfällt die Notwendigkeit zur Wurzelformierung. Darüber hinaus bietet die Prozesskombination eine höhere Toleranz gegenüber Ungenauigkeiten in der Kantenvorbereitung, was die Prozesskomplexität reduziert. Der Einsatz dieses robusteren Verfahrens, das weniger von einer präzisen Kantenvorbereitung abhängig ist, erleichtert die Produktionsvorbereitung, minimiert die Fehleranfälligkeit und senkt die Nachbearbeitungskosten. Dies macht das Laserhybridschweißen besonders attraktiv für Anwendungen im Schiffbau. T2 - 22. Tagung Schweißen in der maritimen Technik und im Ingenieurbau CY - Hamburg, Germany DA - 13.05.2025 KW - Laserhybridschweißen KW - Unterpulverschweißen KW - Kerbschlagbiegeversuch PY - 2025 SP - 87 EP - 98 PB - DVS – Deutsche Verband für Schweißen und verwandte Verfahren e. V AN - OPUS4-63342 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Winkler, Michael T1 - Automated Repair of Gas Turbine Blades Using DED-Arc N2 - Gas turbine blades are critical components in aerospace and power generation, often subject to wear, erosion, and fatigue-induced damage. Traditional repair methods are labor-intensive, costly, prone to inconsistencies, and not rapidly adaptable. This work presents an automated approach for repairing gas turbine blade tips using Wire and Arc Directed Energy Deposition (DED-Arc) in combination with a high-precision point to point registration technique of laser line triangulation (LLT) 3D scans. The proposed workflow begins with affixation of the milled down turbine blade to a work piece manipulator using a 3D printed clamping mechanism and a rough alignment of the turbine tip. Subsequently, the turbine blade’s geometry is acquired using a fully integrated 3D laser triangulation sensor, transforming, and aggregating the captured 2D line data into a 3D scan in the working user coordinate system using live feedback data from a finely calibrated industry robot. This point cloud representation of the real-world turbine blade is then used as the target during an advanced point-to-point shape registration technique transforming the digital representation of the repair process containing all relevant tool path and geometry data into the coordinate system of the real-world turbine blade. Afterwards, the turbine tip is then iteratively repaired whereby the turbine tip geometry is divided into differentiated sections, each with its own optimized process parameter set. A key innovation in this approach is the adaptability of the repair process through a closed-loop monitoring system. After each DED-Arc deposition, a 3D scan is performed to document the deposited geometry, to detect the interaction of the different process parameter sets, to activate an intervention if necessary, and calculate subsequent tool paths based on current geometry data. The results indicate that the combination of precise 3D scan registration with DED-Arc is a viable solution for the industrial-scale repair of gas turbine blades leading to significant reduction in labor, tooling, process, and time related cost. T2 - IIW Assembly CY - Genoa, Italy DA - 22.06.2025 KW - DED-Arc KW - Additive Manufacturing KW - Repair KW - Turbine Blade KW - Automation PY - 2025 AN - OPUS4-63624 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huo, Wenjie A1 - Schmies, Lennart A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael A1 - Wolter, Katinka T1 - Prediction of mean strain from laser beam welding images and detection of defects via strain curves based on machine learning N2 - With the advancement of machine learning, many predictions and measurements in visual tasks can be achieved by convolutional neural networks (CNNs). Solidification hot cracking is a significant defect in laser beam welding, commonly encountered in practical applications. Existing theories indicate that the formation of cracks is closely related to strain accumulation near the solidification front. In this paper, we first leverage supervised Regression networks to design CNNs that achieve real-time average strain estimation for each frame in the collected welding videos. Two different architectures are proposed and compared: the first model stacks two frames at a set interval and feeds them into the network, while the second model extracts image features individually and predicts the results by calculating the correlation between them. Each network has its own advantages in Terms of computational efficiency and accuracy. Finally, we further train a multilayer perceptron (MLP) classification model that can detect the occurrence of cracks based on the predicted strain behaviors. KW - Laser beam welding KW - Mean strain prediction KW - Solidification cracking detection Convolutional neural networks KW - Convolutional neural networks PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644495 DO - https://doi.org/10.1016/j.optlastec.2025.113975 SN - 0030-3992 VL - 192, Part F SP - 1 EP - 8 PB - Elsevier Ltd. AN - OPUS4-64449 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bachmann, Marcel A1 - Putra, Stephen Nugraha A1 - Yang, Fan A1 - Meng, Xiangmeng A1 - Pusbatzkies, Pablo A1 - Rethmeier, Michael T1 - Elucidation of the Laser Beam Energy Attenuation by the Vapor Plume Formation during High Power Laser Beam Welding N2 - In high-power laser beam welding, a common phenomenon is the formation of a keyhole caused by the rapid evaporation of the material. Under atmospheric pressure, this evaporation generates a vapor plume that interacts with the laser beam, leading to energy attenuation and scattering of the laser radiation along its path. These interactions affect the stability of the process and the overall weld quality. This study investigates the influence of the vapor plume on the weld pool and keyhole dynamics during high-power laser beam welding of AlMg3 aluminum alloy through experimental and numerical approaches. The primary goal is to identify key vapor plume characteristics, particularly its length fluctuations, and to improve the accuracy of the numerical models. To achieve this, an algorithm was developed for the automated measurement of the vapor plume length using high-speed imaging and advanced data processing techniques. The measured plume length is then used to estimate the additional vapor heating and laser energy attenuation using the Beer–Lambert law. A refined numerical CFD model, incorporating 3D transient heat transfer, fluid flow, and ray tracing, was developed to evaluate the vapor plume’s impact. Results show that already the time-averaged plume length effectively captures its transient influence and aligns well with experimental weld seam geometries. Additionally, energy scattering and absorption caused by the vapor plume led to a wider weld pool at the top surface. The study also shows an increased percentage of keyhole collapses due to the reduced laser power absorption at the keyhole bottom, further highlighting the importance of accurately modeling vapor plume effects. T2 - International Congress of Applications of Lasers & Electro-Optics 2025 CY - Orlando, USA DA - 12.10.2025 KW - Laser beam welding KW - Vapor plume formation KW - Weld pool KW - Keyhole dynamics KW - Numerical modeling PY - 2025 SP - 1 EP - 10 AN - OPUS4-64817 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Xiangmeng T1 - A statistical investigation of the laser energy absorption and keyhole stability in high-power laser beam welding N2 - The behaviour of the weld pool in high-power laser beam welding is significantly influenced by laser absorption and keyhole stability, which determines the final weld qualities. However, their dynamic features and multi-coupled interactions make in-depth analyses difficult. This study addresses the challenges by conducting a thorough statistical evaluation of the effects of welding parameters on laser absorption and keyhole fluctuations, using experimental investigations and a well-validated numerical model. From a statistical aspect, the laser energy distribution and the keyhole collapse, commonly considered highly time-varying, show clear regularities. Three distinct regions of the time-averaged energy distribution are identified. The possibility of the keyhole collapse positions obeys a universal normal distribution. The statistical data show greater potential in revealing some well-known, industry-related but unclearly explained findings, such as the saturation of the weld penetration with increasing heat input and the physical basis of the contributions of different welding parameters in the porosity reduction. T2 - The 14th International Seminar Numerical Analysis of Weldability CY - Graz, Austria DA - 21.09.2025 KW - Laser beam welding KW - Energy absorption KW - Keyhole stability KW - Multi-physics modelling PY - 2025 AN - OPUS4-64811 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Xiangmeng T1 - A statistical assessment of the laser energy absorption and keyhole stability in high-power laser welding N2 - The behavior of the weld pool in high-power laser beam welding is significantly influenced by laser absorption and keyhole stability, which determines the final weld qualities. However, their dynamic features and multi-coupled interactions make in-depth analyses difficult. This study addresses the challenges by conducting a thorough statistical evaluation of the effects of welding parameters on laser absorption and keyhole fluctuations, using experimental investigations and a well-validated numerical model. From a statistical aspect, the laser energy distribution and the keyhole collapse, commonly considered to be highly time-varying, show clear regularities. Three distinct regions of the time-averaged energy distribution are identified. The possibility of the keyhole collapse positions obeys a universal normal distribution. The statistical data show greater potential in revealing some well-known, industry-related but unclearly explained findings, such as the saturation of the weld penetration with increasing heat input and the physical basis of the contributions of different welding parameters in the porosity reduction. T2 - 78th IIW Annual Assembly CY - Genoa, Italy DA - 22.06.2025 KW - Laser beam welding KW - Energy absorption KW - Keyhole stability PY - 2025 AN - OPUS4-64810 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chaurasia, Prashant Kumar A1 - Fabry, Çağtay A1 - Pittner, Andreas A1 - De, Amitava A1 - Rethmeier, Michael T1 - Automated in situ monitoring and analysis of process signatures and build profiles during wire arc directed energy deposition N2 - Wire arc directed energy deposition (DED-Arc) is an emerging metal additive manufacturing process to build near-net shaped metallic parts in a layer-by-layer with minimal material wastage. Automated in situ monitoring and fast-responsive analyses of process signatures and deposit profiles during DED-Arc are in ever demand to print dimensionally consistent parts and reduce post-deposition machining. A comprehensive experimental investigation is presented here involving real-time synchronous measurement of arc current, voltage, and the deposit profile using a novel multi-sensor monitoring framework integrated with the DED-Arc set-up. The recorded current–voltage transients are used to estimate the time-averaged arc power, and energy input in real time for an insight of the influence of wire feed rate and printing travel speed on the deposit characteristics. A unique attempt is made to represent the geometric profiles of the single-track deposits in a generalized mathematical form corresponding to a segmented ellipse, which has exhibited the minimum root-mean-square error of 0.03 mm. The dimensional inconsistency of multi-track deposits is evaluated quantitatively in terms of waviness using build profile monitoring and automated estimation, which is found to increase with an increase in step-over ratio and energy input. For the multi-track mild steel deposits, the suitable range of step-over ratio for the minimum surface waviness is observed to lie between 0.6 and 0.65. Collectively, the proposed framework of synchronized process monitoring and real-time analysis provides a pathway to achieve dimensionally consistent and defect-free parts, and highlights the potential for closed-loop control systems for a wider industrial application of DED-Arc. KW - Additive Manufacturing KW - Arc welding KW - DED-arc KW - Real-time monitoring and control KW - Dimensional inconsistency PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642029 DO - https://doi.org/10.1007/s40964-025-01333-9 SN - 2363-9512 SP - 1 EP - 20 PB - Springer Science and Business Media LLC CY - Cham AN - OPUS4-64202 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pittner, Andreas T1 - Life cycle assessment of fusion welding processes methodology and implementation N2 - Fusion welding processes in manufacturing are resource-intensive, creating a significant opportunity to reduce their environmental impact. While the environmental effects of these processes are qualitatively understood, quantitatively assessing the key influencing parameters remains challenging. This study presents a welding-specific methodology leveraging life cycle assessment (LCA) to quantitatively measure the environmental footprint of fusion welding technologies. The proposed approach identifies and evaluates the critical parameters that influence the environmental performance of various welding methods, including conventional joint welding and additive manufacturing through the Direct Energy Deposition-Arc (DED-Arc) process. By incorporating real-time resource consumption data, the methodology provides a novel framework for directly linking process parameters to environmental impacts. This research offers a precise and quantitative analysis of the ecological effects of welding processes, supporting their optimization and promoting the development of more sustainable manufacturing practices. T2 - European welding association - executive meeting 2 CY - Milano, Italy DA - 03.12.2024 KW - Life cycle assessment KW - Fusion welding KW - Sensitivity study PY - 2024 AN - OPUS4-62018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pittner, Andreas T1 - Automated arc welding and quality assessment of large scale support structures for offshore wind turbines N2 - Offshore wind energy is a key driver in achieving a carbon dioxide-free industrial sector over the coming decades. However, the foundation systems for offshore wind plants significantly influence the overall installation process, alongside regulatory challenges. The adoption of lightweight design principles in steel construction, such as the use of dissolved load-bearing structures known as jacket foundations, holds substantial promise for reducing resource use, particularly the required volume of steel. This presentation focuses on the complete digitalization of the welding manufacturing and testing processes, enabling fully automated production and quality assessment of tubular nodes, which are critical components of jacket foundation structures. Additionally, the study examines the correlation between seam geometry and fatigue strength through numerical simulations inspired by bionic design principles. It demonstrates that tubular nodes can be welded entirely automatically while accommodating geometric tolerances. Moreover, seam geometries can be precisely manufactured according to the numerical models, significantly enhancing the service life of the structures. Finally, the resource efficiency and reduction in carbon dioxide emissions resulting from these advancements are analyzed through a life-cycle assessment, highlighting the environmental benefits of this approach. T2 - 77th IIW Annual Assembly and International Conference, C-XII: Arc Welding Processes and Production Systems CY - Rhodos, Greece DA - 07.07.2024 KW - Offshore wind KW - Support structures KW - Light-weight construction KW - Automated arc welding PY - 2024 AN - OPUS4-62016 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Chaurasia, Prashant Kumar T1 - Automated In-situ Monitoring and Analysis of Process Signatures and Build Profile During Arc-based Directed Energy Deposition N2 - Automated in-situ synchronous monitoring and analysis of key process signatures during arc-based directed energy deposition (DED) process are the key challenges for layer-by-layer printing of large-scale parts. An attempt is presented here for real-time monitoring of process transients, deposit profile, and quantitative assessment of arc power, energy input and its influence on deposit dimensions. The workflow including setup, job generation and data analysis is fully automated in Python to allow large scale experiments with fast analysis results. T2 - 2nd Online Young Welding Professional International Conference CY - Online meeting DA - 06.02.2025 KW - Additive Manufacturing KW - Arc welding KW - DED-arc KW - Monitoring KW - Deposition profile PY - 2025 AN - OPUS4-62663 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hälsig, André A1 - Eßbach, Tim-Bernd A1 - Scharf-Wildenhain, Ronny A1 - Altobelli, Martin Gabriel A1 - Phadnis, Prathamesh Jayant A1 - Hensel, Jonas A1 - Fabry, Çağtay A1 - Pittner, Andreas A1 - Armansyah, T1 - Qualitätssicherung beim Lichtbogenschweißen N2 - Der fortschreitende Trend der Automatisierung und Dokumentation sowie die wirtschaftliche und technische Optimierung von Fügeaufgaben machen es notwendig, Sensoren zielführend in bestehende und vorhandene Anlagentechnik zu integrieren. Jedoch bietet die reine Datenerfassung alleine nur einen geringen Mehrwert. Erst durch eine optimierte Datenspeicherung, eine intelligente sowie automatische Datenauswertung und -bewertung entsteht ein echter Nutzen für den industriellen Anwender. Zur Qualifizierung einer standardisierbaren Herangehensweise der Qualitätssicherung beim Lichtbogenschweißen wurden mit einer nationalen Arbeitsgruppe bestehende Unstetigkeiten der Qualitätsbeeinflussung geschweißter Bauteile aufgeschlüsselt und definiert. Parallel dazu wurde ein automatisiertes Schweißsystem mit hochgenauer Messtechnik (u. a. Stromstärke, Spannung, Drahtvorschub, Thermokamera, Geometriescanner usw.) ausgerüstet und validiert. Hierfür wurde die Open-Source-Technologie WelDX der BAM genutzt. Anschließend wurden bewusst fehlerhaft geschweißte Nähte im Vergleich zu fehlerfreien Referenzschweißungen hergestellt, Messdaten erfasst und analysiert. Im Rahmen dieses Beitrags werden erste Ergebnisse und Erkenntnisse in Bezug auf die Detektion und Bewertung von Unstetigkeiten beim Lichtbogenschweißen dargestellt. Dabei wurde deutlich, dass alternative Darstellungs- und Analysemethoden wie die Anwendung der Mahalanobis-Distanz im Stromstärke-Spannungs-Diagramm eine eindeutigere Korrelation zwischen Unstetigkeiten und Prozesssignalen ermöglichen. T2 - DVS CONGRESS 2025 CY - Essen, Germany DA - 16.09.2025 KW - Lichtbogenschweißen KW - Qualitätssicherung KW - Forschungsdatenmanagement KW - WelDX PY - 2025 SN - 978-3-96144-298-0 VL - 401 SP - 76 EP - 85 PB - DVS Media GmbH CY - Düsseldorf AN - OPUS4-64565 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -