TY - CONF A1 - Mohr, Gunther T1 - Einfluss der Zwischenlagenzeit und der Bauteilhöhe auf die resultierenden Eigenschaften laserstrahlgeschmolzener austenitischer Stahlbauteile N2 - Das pulverbettbasierte selektive Laserstrahlschmelzen (engl. laser powder bed fusion, L-PBF) ist die am weitesten verbreitete additive Fertigungstechnologie für die Herstellung metallischer Komponenten. Unter der Vielzahl an Einflussfaktoren auf die Qualität und die mechanischen Eigenschaften von L PBF-Bauteilen hat die Zwischenlagenzeit (engl. inter layer time, ILT) bisher kaum Beachtung in der wissenschaftlichen Literatur gefunden, obwohl sie je nach Bauraumausnutzungsgrad stark variieren kann. In diesem Vortrag werden Ergebnisse einer Studie präsentiert, die den Einfluss der ILT in Kombination mit der Bauteilhöhe und unter Berücksichtigung verschiedener Volumenenergiedichten am Beispiel der austenitischen Stahllegierung AISI 316L untersucht. Die Fertigungsprozesse wurden in situ mittels Thermographiekamera überwacht, sodass Informationen über das Abkühlverhalten der Bauteile während des Prozesses gewonnen werden konnten. Es wurden signifikante Effekte der ILT und der Bauteilhöhe auf Wärmeakkumulation, Mikrostruktur, Schmelzbadgeometrie und Härte festgestellt. Ferner konnte ein Anstieg von Defektdichten bei einem gegenseitigen Wechselspiel aus Bauteilhöhe und ILT aufgezeigt werden. Die Zwischenlagenzeit wurde somit als kritischer Faktor für die L-PBF-Fertigung von Realbauteilen identifiziert. T2 - DGM Fachtagung "Werkstoffe und Additive Fertigung" CY - Online meeting DA - 13.05.2020 KW - Laser Powder Bed Fusion KW - Additive Fertigung KW - Zwischenlagenzeit KW - In-situ Monitoring PY - 2020 AN - OPUS4-50788 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Marquardt, R. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Funktional gradierte Materialien auf Basis von Stellite und Stahl im Laserpulver-Auftragschweißen N2 - Das Hinzufügen von Stellite auf Stahl ist eine typische Vorgehensweise um Bauteile gegen Verschleiß und Korrosion zu schützen. Der Sprung in den Materialeigenschaften kann jedoch zu Rissen und somit zum Versagen der Beschichtung führen. Um die Lebensdauer von Beschichtungen zu erhöhen wird daher ein gradierter Übergang mit verschiedenen Materialpaarungen untersucht. T2 - 13. Fachtagung Verschleiss- und Korrosionsschutz von Bauteilen durch Auftragschweißen CY - Haale (Saale), Germany DA - 22.06.2022 KW - FGM KW - DED KW - AM KW - Functionally Graded Materials KW - Additive Manufacturing KW - Directed Energy Deposition PY - 2022 SP - 66 EP - 73 AN - OPUS4-55504 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - El-Sari, B. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Einfluss von Oberflächenbeschichtungen auf die flüssigmetallinduzierte Rissbildung beim Widerstandspunktschweißen von hochfesten Stahlfeinblechen BT - Schlussbericht vom 15.09.2022 zu IGF-Vorhaben Nr. 20812 N : Berichtszeit: 01.10.2019 bis 31.03.2022 N2 - Die Beschichtung hochfester Stahlfeinbleche beeinflusst das Auftreten von flüssigmetallinduzierter Rissbildung (LME). Daher wurden in dieser Arbeit industrieübliche Beschichtungen bei gleichem Grundwerkstoff hinsichtlich ihres Aufbaus und chemischer Zusammensetzung charakterisiert und bezüglich ihrer LME Anfälligkeit untersucht. Aus dieser vergleichenden Untersuchung heraus wurden Potentiale für die Widerstandsfähigkeit gegen LME identifiziert. Diese Potentiale werden experimentell durch den Einsatz einer von der Forschungsstelle entwickelten Methode überprüft. Gegenstand der Untersuchungen waren neben unbeschichteten Proben industrieübliche Zinküberzüge wie Elektrolytisch verzinkt, Feuerverzinkt, Galvannealed und Zink-Magnesium Beschichtungen. Die LME Anfälligkeit dieser unterschiedlichen Überzüge wird mit einem Schweißen unter Zugbelastung Versuchsaufbau untersucht. Dabei ergibt sich die resultierende Anfälligkeit aus den auftretenden Risslängen und der Auftrittswahrscheinlichkeit von LME bei den einzelnen Versuchen. Es konnte eine LME Anfälligkeits-Rangfolge für die Zinküberzüge festgestellt werden. Zink-Magnesium Beschichtungen galten als besonders LME Anfällig, gefolgt von Feuerverzinkt und Galvannealed. Die größte LME Resistenz wurde bei elektrolytisch verzinkten Proben festgestellt. Aus den Ergebnissen werden Handlungsempfehlungen zur Erhöhung der Verarbeitungssicherheit bzw. Schweißpunktqualität abgeleitet. KW - Widerstandspunktschweißen KW - Hochfester Stahl KW - Liquid Metal Embrittlement KW - Flüssigmetallinduzierte Rissbildung KW - Zink PY - 2022 SN - 978-3-96780-030-2 SP - 1 EP - 39 PB - Forschungsvereinigung Stahlanwendung e. V. CY - Düsseldorf AN - OPUS4-58060 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Marquardt, R. A1 - Bähring, S. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Künstliche Neuronale Netze zur Qualitätsprognose von Funktional Gradierten Materialien im laserbasierten Directed Energy Deposition N2 - Durch pulverbasiertes Directed-Energy Deposition lassen sich Gradierungen fertigen, um diskrete Materialübergänge zu vermeiden und die Lebensdauer von Hartschichten zu erhöhen. Die Kombination aus Stahl als Basiswerkstoff und einer verschleiß- und korrosionsbeständigen Co-Cr Legierung verspricht durch Vermeiden von Spannungskonzentrationen das Verhindern von Abplatzungen und Rissen in der Schutzschicht. Um die Qualität des gefertigten Bauteils zu beurteilen, liegen für solche Funktional Gradierten Materialien (FGM) wenig Erkenntnisse vor. Daher wird im Rahmen dieser Studie eine Methodik erarbeitet, um die relative Dichte eines Funktional Gradierten Materials auf Stahl und Co-Cr Basis mittels Maschinendaten zu bestimmen. Anschließend wird unter Einsatz eines künstlichen neuronalen Netzes anhand von Sensordaten die relative Dichte vorhergesagt. Das trainierte Netz erreicht eine Vorhersagegenauigkeiten von 99,83%. Abschließend wird eine Anwendung anhand von einem Demonstrator gezeigt. T2 - 3. Fachtagung Additive Manufacturing CY - Halle, Germany DA - 05.10.2023 KW - Directed Enery Deposition KW - Künstliche Neuronale Netze KW - Additive Manufacturing KW - DED KW - KI KW - AM PY - 2023 SP - 1 EP - 8 PB - SLV Halle AN - OPUS4-58692 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - El-Sari, B. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Verbesserung der Übertragbarkeit eines künstlichen neuronalen Netzes zur Qualitätsvorhersage beim Widerstandspunktschweißen von hochfesten Stählen N2 - Eine typische Automobilkarosserie kann bis zu 5000 Widerstandspunktschweißverbindungen aufweisen, welche hohen Qualitätsanforderungen genügen müssen. Daher ist eine durchgehende Prozessüberwachung unerlässlich. Die Transformation zur E-Mobilität in der Automobilindustrie und die damit einhergehende Reichweitenproblematik treiben die Entwicklung und Einführung neuer hochfester Stähle an. Dies resultiert in einem gesteigerten Fertigungsaufwand hinsichtlich einer stabilen Prozess-führung in der Fügetechnik. Um diesen Anstieg an Komplexität zu bewältigen, sind die Methoden der künstlichen Intelligenz ein geeignetes Mittel. Mit ihnen kann, durch Auswertung der Prozessparameter und -signale, die individuelle Schweißpunktqualität sichergesellt werden. Die Vorhersagegenauigkeit von neuen Daten, also das extrapolieren, stellt für die meisten Algorithmen eine große Herausforderung dar. In dieser Arbeit wird ein künstliches neuronales Netz zur Vorhersage des Punktdurchmessers von Widerstandspunktschweißungen anhand von Prozessparametern implementiert. Die Vorhersagegenauigkeit und Extrapolationsfähigkeit des Modells wird durch die Auswertung des dynamischen Widerstandssignals verbessert. Um die Extrapolationsfähigkeit zu untersuchen, wird die Vorhersagegenauigkeit des Modells mit Daten getestet, die sich in Bezug auf den Werkstoff und der Beschichtungszusammensetzung deutlich von den Trainingsdaten unterscheiden. Dazu wurden mehrere Schweißexperimente mit Werkstoffen verschiedener Hersteller durchgeführt und nur ein Teil der Daten in das Training einbezogen. Die Ergebnisse dieser Arbeit verdeutlichen den positiven Einfluss der Prozesssignale auf die Robustheit des Modells und die Skalierbarkeit der Algorithmen künstlicher neuronaler Netze auf Daten außerhalb des Trainingsraums. T2 - DVS Congress 2023 Große Schweißtechnische Tagung CY - Essen, Germany DA - 11.09.2023 KW - Widerstandspunktschweißen KW - Hochfester Stahl KW - Künstliche Intelligenz KW - Neuronales Netz KW - Fügequalität PY - 2023 SN - 978-3-96144-230-0 SP - 772 EP - 779 AN - OPUS4-58693 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neumann, Benedikt A1 - Biegler, Max A1 - Goecke, Sven-Frithjof A1 - Rethmeier, Michael T1 - Detektion von Bindefehlern beim DED-Arc T1 - Detection of Lack of Fusion during DED-Arc N2 - Based on artificial intelligence (AI) developed for monitoring arc welding, this article presents a deep neural network for monitoring lack of fusion defects in wire arc additive manufacturing of aluminium. The aim is to detect defects in built-up volumes on the basis of weld source data. These can be successfully processed by the algorithm presented and a trained AI. The achieved accuracy of the network is 90 percent. N2 - In dem Beitrag wird aufbauend auf Machine-Learning-Modellen, welche bereits zum Überwachen des Schutzgasschweißen erforscht wurden, ein tiefes neuronales Netz (DNN) zum Monitoring beim DED-Arc von Aluminium vorgestellt. Ziel ist die Detektion von Bindefehlern in den aufgebauten Volumina auf Grundlage von in Echtzeit gemessenen Schweißstromquellensignalen. Es werden Merkmalsvariablen durch Vorverarbeitung extrahiert sowie die Korrelation zwischen den Merkmalsvariablen und den Defekten analysiert. Durch den vorgestellten Algorithmus werden diese automatisiert als Input an ein DNN übergeben. Das entwickelte und trainierte neuronale Netz erkennt anhand signifikanter Merkmale aus den Strom- und Spannungsdaten Bindefehler mit einer Genauigkeit von ca. 90 Prozent. KW - DED-Arc KW - Aluminiumschweißen KW - Bindefehler KW - Prozessüberwachung KW - Maschinelles Lernen KW - Deep Neural Network PY - 2024 DO - https://doi.org/10.1515/zwf-2024-1107 VL - 8 SP - 577 EP - 583 PB - Walter de Gruyter GmbH AN - OPUS4-61630 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Marquardt, R. A1 - Gook, S. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Handgeführtes Laserstrahlschweißen am T-Stoß eines niedrig legierten Stahls N2 - Das handgeführte Laserstrahlschweißen gewinnt in der Industrie zunehmend an Bedeutung, da die hohe Produktivität und die einfache Handhabung Unternehmen wirtschaftliche Vorteile bieten. Derzeit ist der Einsatz in der Industrie jedoch auf Teile mit ästhetischen Anforderungen beschränkt, die häufig aus hochlegiertem Stahl bestehen. Um das Handschweißen mit Laserstrahl auch für Bauteile aus kostengünstigen Stähle mit guten mechanischen Eigenschaften einsetzen zu können, untersucht diese Studie den Einfluss des Schutzgases auf die Porosität am mikrolegierten Stahl HX340LAD mit einer Dicke von 1,5 mm. Getestet wurden die Gase Argon, Stickstoff, CO2 sowie Mischungen aus Argon und CO2 an T-Stöße mit Zusatzdraht. Die Qualifizierung der Porosität erfolgte gemäß DIN EN ISO 13919-1 an Querschliffen als auch mittels Röntgenuntersuchung. Die Ergebnisse zeigen, dass für diesen Stahl die Bewertungsgruppe B mittels CO2 als Schutzgas erreicht werden kann. Stickstoff führt zu Gruppe C, Argon zu D. KW - Handgeführtes Laserstrahlschweißen KW - HHLW KW - Stahl KW - Laser PY - 2025 VL - 2025 IS - 06 SP - 44 EP - 47 PB - DVS Media AN - OPUS4-63345 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Marquardt, R. A1 - Osayi, J. A1 - Kmieciak, S. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Verschleißschutz einer Schneckengeometrie durch funktional gradierte Materialien N2 - Hochbelastete Stahlbauteile lassen sich durch Auftragen von Kobalt-Chrom Legierungen vor Verschleiß schüt-zen. Die plötzliche Änderung der Materialeigenschaften führt jedoch zu Spannungen und Rissen im Anbindungs-bereich. Daraus resultierende Abplatzungen stellen eine Gefahr für die Funktionsfähigkeit der Maschine und damit für Mensch und Umwelt dar. Um die Belastbarkeit der Schutzschicht zu verbessern, kann die Anbindung durch einen gradierten Materialübergang optimiert werden. Diese funktional gradierten Materialien können mit-tels pulverbasiertem Directed Energy Deposition aufgetragen werden. Die Methodik zum Aufbau und zur Quali-tätssicherung solcher Materialien wurde in vorangegangenen Arbeiten für dickwandige Geometrien gezeigt. Für dünnwandige Geometrien ist die Anwendbarkeit bisher unzureichend untersucht worden. Diese Arbeit zeigt am Beispiel einer dünnwandigen gradierten Schneckengeometrie die Einsatzfähigkeit der Methodik. Dafür wird die Gefügestruktur der Gradierung auf Fehler untersucht und der Härteverlauf gemessen. Außerdem wird die relative Dichte anhand eines bereits trainierten neuronalen Netzes vorhergesagt und mit einer Porositätsuntersuchung verglichen. T2 - 14. Tagung Verschleiß- und Korrosionsschutz von Bauteilen durch Auftragschweißen CY - Halle (Saale), Germany DA - 12.06.2024 KW - Directed Enery Deposition KW - Funktionally Graded Material KW - Additive Manufacturing KW - DED KW - FGM KW - AM PY - 2024 AN - OPUS4-62688 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 - 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 - 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 - Fabry, Çağtay T1 - Welding Process Data Management - openBIS workflows and lab integration N2 - Arc welding processes are an important manufacturing technology applied to a wide range of critical materials and components such as offshore constructions, pressure vessels and additive manufacturing. Data management for experimental arc welding research faces the challenge of constantly changing experimental setups, incorporating a wide range of custom sensor integrations. Measurements include timeseries process and temperature recordings, 3D-geometry data and video recordings of the process from a sub-millisecond scale to multiple hour-long experiments. In addition, various manual pre-processing steps of the workpieces need to be considered to track the complete manufacturing process and its analysis – from raw materials to final dataset and publication. As a unified RDM system, the BAM Data Store offers the capability to incorporate all steps – albeit not without its own challenges. The talk gives an overview of the different workflows and processing steps along the welding experiments together with their integration into the BAM Data Store. Current solutions and ongoing integration work is explained and discussed. This includes the direct integration and upload of automated processing steps into the Data Store from different machines and sensors using custom Python APIs. Ultimately the complete processing chain across multiple internal steps should be represented in the Data Store. T2 - openBIS user group meeting 2025 CY - Berlin, Germany DA - 22.09.2025 KW - Data Store KW - Openbis KW - Research Data Management KW - Research data KW - Digitalisation PY - 2025 AN - OPUS4-64203 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pittner, Andreas A1 - Winterkorn, René T1 - Life cycle assessment of fusion welding processes considering upstream and downstream process steps N2 - In manufacturing, fusion welding processes consume significant resources, presenting a significant opportunity for reducing environmental impact. Although there is a qualitative understanding of the environmental implications of these processes, a quantitative assessment of key parameters remains complex. This study introduces a welding-specific methodology that employs life cycle assessment (LCA) to quantitatively evaluate the environmental footprint of fusion welding technologies. Our approach identifies and analyses the principal parameters affecting the environmental performance of various welding techniques, including traditional joint welding and additive manufacturing via the Direct Energy Deposition-Arc (DED-Arc) process. Real-time resource usage data is integrated to offer an innovative framework for directly deriving environmental impacts. This research contributes to optimising welding processes by providing a precise and quantifiable measure of their ecological impact. This facilitates the advancement of sustainable manufacturing practices. T2 - Joining Smart Technologies - International Automotive Conference CY - Wels, Austria DA - 10.05.2023 KW - Life Cycle Assessment KW - Arc welding KW - Additive manufacturing KW - DED-Arc PY - 2023 AN - OPUS4-59494 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - El-Sari, B. A1 - Biegler, M. A1 - Gook, S. A1 - Rethmeier, Michael T1 - KI zur Prozessüberwachung im Unterpulverschweißen N2 - Beim Unterpulverschweißen sind die Prozessgeräusche ein Indikator für eine gute Fügequalität. Diese Beurteilung kann i.d.R. nur von einer erfahrenen Fachkraft durchgeführt werden. Eine kürzlich entwickelte künstliche Intelligenz kann automatisch das akustische Prozesssignal anhand vortrainierter Merkmale klassifizieren und die Fügequalität anhand des Geräuschs beurteilen. Der Algorithmus, einmal richtig trainiert, kann den Prüfaufwand beim Unterpulverschweißen deutlich reduzieren. KW - Unterpulverschweißen KW - Künstliche Intelligenz KW - Prozessüberwachung KW - Körperschall PY - 2024 SP - 1 EP - 2 AN - OPUS4-59483 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pittner, Andreas A1 - Winterkorn, René T1 - Life cycle assessment of fusion welding processes strategies and implementation N2 - In manufacturing, fusion welding processes use a lot of resources, which presents an opportunity to reduce environmental impact. While there is a general understanding of the environmental impact of these processes, it is difficult to quantitatively assess key parameters. This study introduces a welding-specific methodology that uses life cycle assessment (LCA) to evaluate the environmental impact of fusion welding technologies. Our approach analyses the main parameters that affect the environmental performance of different welding techniques, including traditional methods and additive manufacturing through the Direct Energy Deposition-Arc (DED-Arc) process. We integrate real-time resource usage data to offer an innovative framework for directly deriving environmental impacts. This research contributes to optimising welding processes by providing a precise and quantifiable measure of their ecological impact, facilitating the advancement of sustainable manufacturing practices. T2 - CEMIVET - Circular Economy in Metal Industries CY - Berlin, Germany DA - 06.06.2023 KW - Life Cycle Assessment KW - Fusion welding KW - Additive manufacturing KW - DED-Arc PY - 2023 AN - OPUS4-59499 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fabry, Çağtay T1 - Towards arc welding reference data: Open Science laboratories at BAM N2 - As industries move for ever faster development and adoption cycles of emerging new technologies in the field of welding, the meticulous and longer-winded approach of the scientific research process can feel harder to integrate. To help bridge this gap and increase the speed, quality, and adoption rate of publicly funded research, the Bundesanstalt für Materialforschung und -prüfung (BAM) continues to work towards enabling scientists with direct access to necessary software tools and - in the future – highest quality welding research reference data to further foster collaborations. On the experimental side, the arc welding group at BAM division 9.3 “welding technologies” is continuing to expand and upgrade its capacities of robotic welding systems with integrated state of the art sensor technologies and software solutions. This allows all experiments to be recorded and measured in micro-millimeter accuracy and at sub-millisecond precision, including welding process data, complete spatial geometry and temperature measurements, process video recordings and more. The custom software-based solutions and interfaces allow scaling of the welding systems from large thick plate offshore applications to small additive repair weldments in wind turbine blades to multi-hour continuous weldments in additive manufacturing applications. In addition to the data gathered during the welding process itself, the relevant testing results and materials properties produced at BAM or externally can be integrated seamlessly. This allows detailed traceability of all results back to the actual welding process. Regardless of the scope and application, complete datasets can be made accessible for research or industry partners in the highest resolution based on the open source WelDX (welding data exchange) file format. Figure 1. Welding experiment representation including dynamic process data, cross-section imaging and hardness measurements from a single weldx file. The talk will give an overview of the experimental facilities and workflows as well as current software developments with a focus on research data quality assurance, traceability, and accessibility. Based on the integration into latest research trends and activities of the “welding technologies” division, the path to publishing reference datasets for arc welding process for various applications and materials is outlined and discussed. T2 - 4th Symposium on Materials and Additive Manufacturing - Additive 2024 CY - Berlin, Germany DA - 12.06.2024 KW - Additive Manufacturing KW - Arc welding KW - DED-arc KW - Research data KW - Reference data PY - 2024 AN - OPUS4-60249 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fabry, Çağtay T1 - WelDX – progress report on the welding data exchange format N2 - The presentation shows the current development status of the Welding Data Exchange (weldx) format based on the Advanced Scientific Data Format (ASDF). The use of a complete single pass arc welding experiment example stored in a single weldx file and validated against a predefined schema definition is presented. The example includes generic experimental metadata, the workpiece geometry and materials definition following associated standards, the weld process spatial movement description, the welding process parameter descriptions and welding process measurements. The inclusion of 3D scan data of the workpiece description is also included. The full code and data is available on GitHub: https://github.com/BAMWelDX/IIW2021_AA_CXII T2 - 2021 IIW Annual Assembly and International Conference on welding and Joining CY - Online meeting DA - 07.07.2021 KW - Arc welding KW - Digitalization KW - Open science KW - Research data management KW - WelDX PY - 2021 AN - OPUS4-53401 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Üstündag, Ömer A1 - Bakir, Nasim A1 - Gook, S. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Hybrid Laser-Arc Welding of Thick-Walled, Closed, Circumferential Pipe Welds N2 - The application of hybrid laser-arc welding (HLAW) for joining closed circumferential welds is a challenge due to the high risk of forming a defective overlap area with a shrinkage void or solidification cracks in the material thickness. A series of HLAW experiments were performed to understand the development of a faulty overlap area when closing the circumferential weld. Welding trials on flat specimens and pipe segments were supported by numerical analyses in which the thermomechanical behavior of the welds in the overlap area was investigated. Different process control strategies were tested, including variations in defocusing levels and the overlap length. The newly developed HLAW head, including laser optics with a motor-driven collimation system, made it possible to defocus the laser beam during welding without disturbing the stability of the welding process. High-level defocusing of the laser beam of more than 40 mm relative to the specimen surface with a resulting beam diameter of > 2.9 mm, and in combination with a short overlap length of 15 mm, was promising with respect to the formation of a desired cup-shaped weld profile that is resistant to solidification cracks. KW - Hybrid Laser-Arc Welding KW - Thick-Walled Steel KW - High-Power Welding KW - Crater KW - Pipe Welding PY - 2022 DO - https://doi.org/10.29391/2022.101.002 SN - 0043-2296 VL - 101 IS - 1 SP - 15 EP - 26 PB - American Welding Society CY - New York, NY AN - OPUS4-55508 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Strobl, Dominic T1 - Real-time Bead-on-Plate weld Simulation for Wire Arc Additive Manufacturing using Reduced Order modelling coupled with stochastic model Calibration N2 - Numerical simulations are essential in predicting the behavior of systems in many engineering fields and industrial sectors. The development of accurate virtual representations of actual physical products or processes (also known as digital twins) allows huge savings in cost and resources. In fact, digital twins would allow reducing the number of real, physical prototypes, tests, and experiments, thus also increasing the sustainability of production processes and products’ lifetime. Standard numerical methods fail in providing real time simulations, especially for complex processes such as additive manufacturing applications. This work aims to use a reduced order model for efficient wire arc additive manufacturing simulations, calibrations and real-time process control. Model reduction, e.g. the proper generalized decomposition [1,2] method, is a popular concept to decrease the computational effort. A new mapping approach [3] was applied to simulate a moving heat source with the proper generalized decomposition. Using this procedure even complex models can be simulated in real-time. The physical model is later on calibrated with the use of a stochastic model updating process and the reduced order model, leading to an optimized real-time simulation. In this contribution, a proper generalized decomposition model for a bead-on-plate wire arc additive manufacturing is presented. It is also coupled with a stochastic model updating process identifying the heat source characteristics as well as the boundary conditions of the transient thermal problem, whereas the heat source shape is simulated using a Goldak heat source T2 - 15th World Congress on Computational Mechanics (WCCM-XV) CY - Yokohama, Japan DA - 31.07.2022 KW - Wire arc additive manufacturing KW - Reduced order modelling KW - Model calibration PY - 2022 AN - OPUS4-55576 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fabry, Çağtay T1 - WelDX - a file format for processing and archiving welding research data N2 - The talk gives an introduction into gas metal arc welding and its relation to plasma science as well as current challenges in welding research concerning research data management and the application of the FAIR principles. The WelDX project is introduced and the main goals are discussed and contrasted with the current features of the weldx API. Different internal and public facing use cases focusing on research data management and their implementation using weldx are presented. The interactive part of the presentation displays some advanced multi layer use cases and data analysis using the weldx API as well as the integration of materials properties into weldx. T2 - International Workshop on FAIR Data in Plasma Science CY - Online meeting DA - 16.05.2022 KW - WelDX KW - Open science KW - Research data management KW - Arc welding KW - Digital transformation PY - 2022 AN - OPUS4-55153 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Marquardt, R. A1 - Osayi, J. A1 - Kmieciak, S. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Verschleißschutz einer Schneckengeometrie durch funktional gradierte Materialien N2 - Hochbelastete Stahlbauteile lassen sich durch Auftragen von Kobalt-Chrom Legierungen vor Verschleiß schützen. Die plötzliche Änderung der Materialeigenschaften führt jedoch zu Spannungen und Rissen im Anbindungsbereich. Daraus resultierende Abplatzungen stellen eine Gefahr für die Funktionsfähigkeit der Maschine und damit für Mensch und Umwelt dar. Um die Belastbarkeit der Schutzschicht zu verbessern, kann die Anbindung durch einen gradierten Materialübergang optimiert werden. Diese funktional gradierten Materialien können mittels pulverbasiertem Directed Energy Deposition aufgetragen werden. Die Methodik zum Aufbau und zur Qualitätssicherung solcher Materialien wurde in vorangegangenen Arbeiten für dickwandige Geometrien gezeigt. Für dünnwandige Geometrien ist die Anwendbarkeit bisher unzureichend untersucht worden. Diese Arbeit zeigt am Beispiel einer dünnwandigen gradierten Schneckengeometrie die Einsatzfähigkeit der Methodik. Dafür wird die Gefügestruktur der Gradierung auf Fehler untersucht und der Härteverlauf gemessen. Außerdem wird die relative Dichte anhand eines bereits trainierten neuronalen Netzes vorhergesagt und mit einer Porositätsuntersuchung verglichen. T2 - 14. Tagung Verschleiß- und Korrosionsschutz von Bauteilen durch Auftragschweißen CY - Halle a. d. Saale, Germany DA - 12.06.2024 KW - Directed Enery Deposition KW - Funktionally Graded Material KW - Additive Manufacturing KW - DED KW - FGM KW - AM PY - 2024 SP - 1 EP - 7 PB - SLV Halle AN - OPUS4-60721 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Raute, Julius A1 - Beret, Alexander A1 - Biegler, Max A1 - Rethmeier, Michael T1 - Ökobilanzierung in der additiven Fertigung – Laser- vs. Elektronenstrahl N2 - Die additive Fertigung gewinnt für industrielle Anwendungen zunehmend an Bedeutung. In diesem Zusammenhang sind Verfahren der Directed Energy Deposition (DED) besonders gefragt, um hohe Aufbauraten zu erreichen. Neben den bekannten laserstrahlbasierten Verfahren hat auch der Elektronenstrahl die industrielle Marktreife erreicht. Das Wire Electron Beam Additive Manufacturing bietet zum Beispiel Vorteile bei der Verarbeitung von Kupferwerkstoffen. In der Literatur wird die höhere Energieeffizienz und die daraus resultierende Verbesserung der CO2-Bilanz des Elektronenstrahls hervorgehoben. Es fehlt jedoch an praktischen Studien mit Messdaten, um das Potenzial der Technologie zu quantifizieren. In dieser Arbeit wird eine vergleichende Ökobilanz zwischen der additiven Fertigung mit Draht und Elektronenstrahl (DED-EB) und der additiven Fertigung mit Laserstrahl und Pulver (DED-LB) durchgeführt. Dazu werden die Ressourcen für die Herstellung ermittelt, ein Testbauteil mit beiden Verfahren hergestellt und der gesamte Energieverbrauch gemessen. Die Umweltauswirkungen werden dann mit den Faktoren Treibhauspotenzial (GWP100), Ozonbildungspotenzial (POCP), Versauerungspotenzial (AP), Eutrophierungspotenzial (EP) abgeschätzt. Es zeigt sich, dass das Wire Electron Beam Additive Manufacturing durch einen deutlich geringeren Energiebedarf gekennzeichnet ist. Darüber hinaus gewährleistet die Verwendung von Draht eine größere Ressourceneffizienz, was zu insgesamt besseren Ökobilanzergebnissen führt. KW - Ökobilanzierung (LCA) KW - Additive Fertigung KW - Directed Energy Deposition KW - Kupfer KW - Wire Electron Beam Additive Manufacturing PY - 2024 SP - 26 EP - 32 AN - OPUS4-62234 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rethmeier, Michael T1 - Laser and hybrid welding with ultra high power lasers N2 - Welding with high-power lasers has a history of over 30 years. With the introduction of high-powerCO2 lasers, the subject was investigated as early as the 1990s as part of various research projects. A renewed interest in the subject was awakened with the market launch of high-brilliance, high-power fibre and disc lasers at the beginning of the 2000s. In industrial production, the use of high-power lasers for welding shipbuilding constructions at the same time as for mobile crane construction is mainly associated with low-alloy high-strength steels with a maximum wall thickness of 15 mm. The use of high-power multi 10kW lasers for even greater sheet thicknesses (20mm-100 mm) promises significantly greater advantages [1]. For these wall thicknesses the economic, technological and ecological advantages of the process over conventional welding methods become especially clear and visible [2]. Despite numerous research projects on this topic, laser technology still faces a number of hurdles that need to be overcome. The new lasers with scalable laser powers up to 100 kW and the application of an electromagnetic weld pool support as well as local vacuum environment widen the possible application range tremendously. In this contribution, the authors address the technical solutions for high-power laser beam welding in the field of thick sheet metal applications, highlight the technological and normative challenges in the industrial implementation of the process and present a perspective for the first concrete applications in the field of off-shore wind energy. T2 - Stuttgarter Laser Tage CY - Stuttgart, Germany DA - 04.06.2024 KW - High-power laserbeam welding KW - Thick plates KW - Electromagnetic weld pool support PY - 2024 AN - OPUS4-62412 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rethmeier, Michael T1 - Single pass laser vacuum welding of thick steel plates using electromagnetic support N2 - The increasing demand for renewable energy produced by offshore wind turbines goes along with an increased demand in the production of offshore wind turbine foundations, so called “monopiles”, which are made by joining thick metal sheets. The industrial standard of multi-layer submerged arc welding (SAW) for joining of thick metal sheets is the current bottleneck in the production of monopiles. A possible increase in productivity by the implementation of high-power laser welding in a newly developed mobile vacuum chamber (MoVac) and an electromagnetic root support is the subject of this study. Single run butt welds are performed in flat position on S355 mild steel of thicknesses up to 80 mm using a disc laser system with 1030 nm wavelength and a maximum output of 60 kW. The laser optic is fixed on the MoVac-System which is held and manipulated by an articulated robot. T2 - 13th CIRP Conference on Photonic Technologies [LANE 2024] CY - Furth, Germany DA - 15.09.2024 KW - Laser beam welding KW - Laser welding with mobile vacuum PY - 2024 AN - OPUS4-62413 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fabry, Çağtay T1 - Welding Process Data Management - Perspectives on the BAM Data Store N2 - Arc welding processes are an important manufacturing technology applied to a wide range of critical materials and components such as offshore constructions, pressure vessels and additive manufacturing. Data management for experimental arc welding research faces the challenge of constantly changing experimental setups, incorporating a wide range of custom sensor integrations. Measurements include timeseries process and temperature recordings, 3D-geometry data and video recordings of the process from a sub-millisecond scale to multiple hour-long experiments. In addition, various manual pre-processing steps of the workpieces need to be considered to track the complete manufacturing process and its analysis – from raw materials to final dataset and publication. As a unified RDM system, the BAM Data Store offers the capability to incorporate all steps – albeit not without its own challenges. The talk gives an overview of the different workflows and processing steps along the welding experiments together with their integration into the BAM Data Store. Current solutions and ongoing integration work is explained and discussed. This includes the direct integration and upload of automated processing steps into the Data Store from different machines and sensors using custom Python APIs. Ultimately the complete processing chain across multiple internal steps should be represented in the Data Store. T2 - Data Store Days CY - Berlin, Germany DA - 09.03.2025 KW - Data Store KW - Openbis KW - Research Data Management KW - Reference Data KW - Welding PY - 2025 AN - OPUS4-62976 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Neumann, B. A1 - Gottschalk, G.-F. A1 - Biegler, M. A1 - Goecke, S.-F. A1 - Rethmeier, Michael T1 - Detektion von Bindefehlern mittels neuronaler Netze bei DED-Arc/M von Aluminium anhand von Echtzeit- Schweißstromquellendaten N2 - Mit der Anwendung des Schutzgasschweißens für additive Strukturen wird aufbauend auf Machine-Learning-Modellen, welche bereits zum Überwachen beim Verbindungsschweißen erforscht wurden, ein tiefes neuronales Netz (DNN) zum Monitoring beim DED-Arc/M von Aluminium vorgestellt. Ziel des Machine Learning Modells ist das Identifizieren von Bindefehlern in den aufgebauten Volumina mit prozessbegleitend gemessenen Schweißstromquellensignalen als Input. Es werden durch Algorithmen Merkmalsvariablen in der Vorverarbeitung der Daten extrahiert und die Korrelation zwischen den Merkmalsvariablen und den Bindefehlern analysiert. Durch den vorgestellten Algorithmus werden diese automatisiert als Input an ein DNN übergeben. Diese Arbeit untersucht die Genauigkeit der Klassifizierung von verschiedenen DNN-Architekturen mit jeweils 4 verdeckten Schichten. Als Trainings- und Testsatz werden randomisiert extrahierte Merkmale von defektfreien und fehlerhaften Proben verwendet, wobei Bindefehler zum Teil absichtlich provoziert werden. Das entwickelte neuronale Netz erkennt anhand signifikanter Merkmale aus den Strom- und Spannungsdaten Bindefehler mit einer Genauigkeit von ca. 90%. T2 - 45. Assistentenseminar Füge- und Schweißtechnik CY - Niederaudorf, Germany DA - 09.11.2024 KW - DED-Arc/M KW - Aluminiumschweißen KW - Prozessüberwachung KW - Machine Learning KW - Deep Neural Network KW - Bindefehler PY - 2025 SP - 139 EP - 144 PB - DVS Media GmbH AN - OPUS4-64838 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gottschalk, Götz-Friedrich A1 - Chaurasia, Prashant Kumar A1 - Goecke, Sven-Frithjof T1 - Zero-defect Printing with DED-GMA via Adaptive Controls N2 - Gas metal arc assisted directed energy deposition (DED-GMA) is a metal additive manufacturing process for fabricating large-scale parts with a higher printing rate. An accurate monitoring and control of the melt pool geometric features is critical for printing zero-defect parts. In this study, the melt pool thermography is used for the real-time detection of the melt pool boundary, centreline, and transient cooling time using an efficient deep learning technique. The presented real-time process monitoring and control methodology using deep learning allows adaptive control of the DED-GMA process. T2 - Twenty-Second International Conference on Flow Dynamics (ICFD 2025) CY - Sendai, Japan DA - 10.11.2025 KW - Additive manufacturing KW - DED-Arc KW - Monitoring KW - Control PY - 2025 SP - 1332 EP - 1335 AN - OPUS4-64837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Fabry, Çağtay A1 - Hirthammer, Volker A1 - Scherer, Martin K. T1 - weldx-widgets: advanced visualisation and jupyter widgets for weldx N2 - This package provides advanced visualisation and interactive widgets for the weldx core package. KW - Weldx KW - Welding KW - Research data KW - Visualisation PY - 2025 DO - https://doi.org/10.5281/zenodo.17790485 PB - Zenodo CY - Geneva AN - OPUS4-64973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Fabry, Çağtay T1 - pytcs: a TwinCAT Scope text export file reader N2 - A Python package for reading exported TwinCAT Scope Files. Export your TwinCAT Scope .svdx files to .txt/.csv and read them into Python. KW - Python KW - TwinCAT Scope KW - File reader KW - File format KW - Measurement data PY - 2025 DO - https://doi.org/10.5281/zenodo.17791125 PB - Zenodo CY - Geneva AN - OPUS4-64975 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krankenhagen, Rainer A1 - Chaudhuri, Somsubhro A1 - Pittner, Andreas A1 - Winterkorn, Rene A1 - de Finis, Rosa A1 - Palumbo, Davide A1 - Galietti, Umberto T1 - Thermographic investigation of the anisotropic behaviour of additively manufactured AISI316 steel using DED-Arc N2 - Additive manufacturing is one of the most promising techniques for industrial production and maintenance, but the specifics of the layered structure must be considered. The Direct Energy Deposition-Arc process enables relatively high deposition rates, which is favourable for larger components. For this study, specimens with different orientations were prepared from one AISI316 steel block – parallel and orthogonal to the deposition plane. Quasistatic tensile loading tests were carried out, monitored by an infrared camera. The obtained surface temperature maps revealed structural differences between both orientations. The consideration of surface temperature transients yields more details about the behaviour of the material under tensile loading than the conventional stress-strain-curve. These preliminary investigations were supplemented by thermographic fatigue trials. Although the anisotropy was also observed during fatigue loading the fatigue behaviour in general was the same, at least for both inspected specimens. The presented results demonstrate the abilities and the potential of thermographic techniques for tensile tests. T2 - 17th Quantitative Infrared Thermography Conference CY - Bologna, Italy DA - 07.07.2025 KW - Thermoelastic effect KW - Wire-arc-additive manufacturing KW - thermal stress analysis KW - fatigue testing PY - 2026 DO - https://doi.org/10.21611/qirt-2024-029 SP - 1 EP - 8 AN - OPUS4-65372 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dak, Gaurav A1 - Barik, Birendra Kumar A1 - Chaurasia, Prashant Kumar A1 - Gottschalk, Götz-Friedrich A1 - Shahane, Akshay Manoj A1 - Goecke, Sven-F. A1 - De, Amitava T1 - Probing dimensional consistency of deposited structures during out-of-position wire arc directed energy deposition N2 - Wire arc directed energy deposition (DED-Arc) using a gas metal arc (GMA) welding power source is cited as DED-GMA that fabricates a part by layer-by-layer deposition of molten wire droplets along horizontal and out-of-position inclined trajectories. For the out-of-position trajectories, a smooth deposition of material is impaired by the gravitational force on the molten wire droplets, resulting in uneven and inconsistent deposit profiles. We present here a detailed experimental investigation to realize the effect of the out-of-position inclinations on the quality of the deposited structure for DED-GMA with a steel and an aluminium filler wire. The evolution of the droplet transfer and melt pool during the out-of-position inclined deposition is probed through high-speed videography at different baseplate angles and commonly used scanning strategies. An analytical model is proposed further based on force equilibrium analysis for a prior estimation of the out-of-position inclined deposit profile, which can help design dimensionally consistent and structurally sound parts using DED-GMA. KW - DED-Arc KW - Additive manufacturing KW - Out-of-position deposition KW - High-speed videography KW - Force PY - 2025 DO - https://doi.org/10.1007/s40194-025-02291-0 SN - 0043-2288 SP - 1 EP - 20 PB - Springer Science and Business Media LLC AN - OPUS4-65350 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Barik, Birendra Kumar A1 - Chaurasia, Prashant Kumar A1 - Kumar, Vikram A1 - Dak, Gauravkumar Roshanlal A1 - Goecke, Sven-F. A1 - De, Amitava T1 - Probing smartphone-based photogrammetry for part profiling in wire arc directed energy deposition N2 - Fast dynamic part profiling during wire arc directed energy deposition (DED-Arc) is required to maintain the dimensional consistency of the fabricated part as it is printed over several overlapped tracks and successive layers. The metrology methods such as laser scanning, though accurate, are costly and less flexible for monitoring of layer-wise deposition. Photogrammetry is an optical measurement technique to reconstruct a 3D geometry using a series of 2D images in different orientations to ensure complete coverage. We propose here a novel attempt for rapid dimensioning of the deposit geometry using smartphone-based photogrammetry for wire arc directed energy deposition (DED-Arc). The recorded images from multiple viewpoints are used for feature extraction and matching and triangulation-based 3D reconstruction of the deposit geometry using open-source software. The reconstructed deposit surface is compared with the original CAD geometry to compare the dimensional consistency of parts during the DED-Arc process. Experimental validation is performed on both simple (cuboid) and complex (hollow cylindrical) aluminum geometries, as well as a steel deposit against laser scanning data. The results demonstrate that the smartphone-based photogrammetry can capture the layer-wise geometry variations with the maximum height deviations well within 15% of the laser scan measurements. Although reconstruction and post-processing times are slightly longer in photogrammetry, the approach provides a flexible, accessible, and cost-effective alternative for part profile monitoring. KW - DED-Arc KW - Monitoring KW - Dimensional consistency KW - 3D reconstruction KW - Part profiling PY - 2025 DO - https://doi.org/10.1007/s40194-025-02273-2 SN - 0043-2288 SP - 1 EP - 14 PB - Springer Science and Business Media LLC AN - OPUS4-65084 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Vinzenz A1 - Klement, Oliver A1 - Sander, Steffen A1 - Biegler, Max A1 - Rethmeier, Michael T1 - Recycling of Stainless Steel Milling Chips for Additive Manufacturing: A Three-Stage Comminution Approach Using a Fine Impact Mill N2 - The production of conventional metal powders for additive manufacturing process is energy intensive and costly. This study introduces a sustainable alternative by recycling stainless steel milling chips as feedstock for laser-powder directed energy deposition. The recycling process employs a three-stage mechanical comminution method utilizing a fine impact mill UPZ100 from Hosokawa Alpine AG. Characterization of the resulting powders is conducted through particle morphology analysis, flowability tests, and mechanical property assessments. The chip-derived powders exhibit comparable aspect ratios and sphericity to conventional water atomized powders, though with reduced flowability due to a pronounced fine fraction content. Elevated levels of oxides are observed, leading to the formation of an oxide layer on specimen blocks, without impairing the mechanical properties. Analyses of porosity, microstructure, and hardness indicate no significant differences when compared to conventional powders from water or gas atomization. This recycling approach not only mitigates waste but also enhances the potential for a circular and sustainable manufacturing process in the additive manufacturing industry and beyond. KW - Directed Energy Deposition KW - Recycling KW - Stainless steel KW - Comminution KW - Powder characteristics PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652037 DO - https://doi.org/10.1088/1757-899X/1332/1/012014 SN - 1757-8981 VL - 1332 IS - 1 SP - 1 EP - 7 PB - IOP Publishing AN - OPUS4-65203 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pittner, Andreas T1 - Adaptive manufacturing strategies for DED-Arc: Case studies on high-strength aluminium alloys and gas-turbine blade repair N2 - In this presentation, we showcase BAM’s current research activities on DED-Arc/M processes, covering both the manufacture of novel high-strength aluminium alloys and the development of automated repair strategies for gas turbine blades, with a focus on robust process control and repeatable component quality. T2 - 12. Wissenschaftliches Kolloquium im Rahmen des SFB/TRR 375 "Multifunktionale Hochleistungskomponenten aus hybriden porösen Materialien" CY - Online meeting DA - 05.02.2026 KW - DED-Arc KW - Automation KW - Quality assessment PY - 2026 AN - OPUS4-65472 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ávila Calderón, Luis T1 - Low cycle fatigue behavior of DED-L Ti-6AL-4V N2 - Laser powder-based directed energy deposition (DED-L) is a technology that offers the possibility for 3D material deposition over hundreds of layers and has thus the potential for application in additive manufacturing (AM). However, to achieve broad industrial application as AM technology, more data and knowledge about the fabricated materials regarding the achieved properties and their relationship to the manufacturing process and the resulting microstructure is still needed. In this work, we present data regarding the low-cycle fatigue (LCF) behavior of Ti-6Al-4V. The material was fabricated using an optimized DED-L process. It features a low defect population and excellent tensile properties. To assess its LCF behavior two conventionally manufactured variants of the same alloy featuring different microstructures were additionally tested. The strain-controlled LCF tests were carried out in fully reversed mode with 0.3 % to 1.0 % axial strain amplitude from room temperature up to 400°C. The LCF behavior and failure mechanisms are described. For characterization, optical microscopy (OM), scanning electron microscopy (SEM), and micro-computed tomography (µCT) were used. The low defect population allows for a better understanding of the intrinsic material’s properties and enables a fairer comparison against the conventional variants. The fatigue lifetimes of the DED-L material are nearly independent of the test temperature. At elevated test temperatures, they are similar or higher than the lifetimes of the conventional counterparts. At room temperature, they are only surpassed by the lifetimes of one of them. The principal failure mechanism involves multiple crack initiation sites. T2 - Ninth International Conference on Low Cycle Fatigue (LCF9) CY - Berlin, Germany DA - 21.06.2022 KW - AGIL KW - Additive Manufacturing KW - Ti-6Al-4V KW - Low-Cycle-Fatigue KW - Microstructure PY - 2022 AN - OPUS4-55123 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ulbricht, Alexander T1 - Separation of the Formation Mechanisms of Residual Stresses in LPBF 316L N2 - Rapid cooling rates and steep temperature gradients are characteristic of additively manufactured parts and important factors for the residual stress formation. This study examined the influence of heat accumulation on the distribution of residual stress in two prisms produced by Laser Powder Bed Fusion (LPBF) of austenitic stainless steel 316L. The layers of the prisms were exposed using two different border fill scan strategies: one scanned from the centre to the perimeter and the other from the perimeter to the centre. The goal was to reveal the effect of different heat inputs on samples featuring the same solidification shrinkage. Residual stress was characterised in one plane perpendicular to the building direction at the mid height using Neutron and Lab X-ray diffraction. Thermography data obtained during the build process were analysed in order to correlate the cooling rates and apparent surface temperatures with the residual stress results. Optical microscopy and micro computed tomography were used to correlate defect populations with the residual stress distribution. The two scanning strategies led to residual stress distributions that were typical for additively manufactured components: compressive stresses in the bulk and tensile stresses at the surface. However, due to the different heat accumulation, the maximum residual stress levels differed. We concluded that solidification shrinkage plays a major role in determining the shape of the residual stress distribution, while the temperature gradient mechanism appears to determine the magnitude of peak residual stresses. T2 - MLZ User Meeting 2020 CY - Online meeting DA - 08.12.2020 KW - Computed tomography KW - Neutron diffraction KW - X-ray diffraction KW - Additive manufacturing KW - Residual stress KW - Thermography KW - LPBF KW - Laser Powder Bed Fusion PY - 2020 AN - OPUS4-51793 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ávila Calderón, Luis T1 - Kriech- und Bruchverhalten von additiv hergestelltem austenitischem Stahl 316L. Vergleich zum konventionellen Werkstoff. N2 - Eine kritische Aufgabe im Rahmen der Etablierung von Prozess-Struktur-Eigenschafts-Performance-Beziehungen bei der additiven Fertigung (AM) von Metallen ist die Ermittlung von zuverlässigen und gut dokumentierten Kennwerten zum Materialverhalten sowie das Schaffen von Wissen über die Struktur-Eigenschafts-Korrelation. Schließlich ist dies die Grundlage für die Entwicklung gezielterer Prozessoptimierungen und zuverlässigerer Lebensdauer-Vorhersagen. In diesem Zusammenhang zielt dieser Beitrag darauf ab, Daten und Erkenntnisse über das Kriechverhalten des austenitischen Edelstahls 316L zu liefern, der mittels Laser-Powder-Bed-Fusion (L-PBF) hergestellt wird. Um dieses Ziel zu erreichen, wurden Proben aus konventionellem warmgewalztem sowie AM-Material gemäß den bestehenden Normen für konventionelles Material geprüft und vor und nach dem Versagen mikrostrukturell charakterisiert. Die Probekörper wurden aus einzelnen Blöcken des AM-Materials gefertigt. Die Blöcke wurden mit einer Standard-Scan- und Aufbaustrategie hergestellt und anschließend wärmebehandelt. Das Kriechverhalten wird anhand der Kriechlebensdauer und ausgewählter Kriechkurven und Kennwerte beschrieben und vergleichend bewertet. Der Einfluss von Defekten und Mikrostruktur auf das Materialverhalten wird anhand von zerstörenden und zerstörungsfreien Auswertungen an ausgewählten Proben analysiert. Der AM-Werkstoff zeigt kürzere Kriechlebensdauern, erreicht das sekundäre Kriechstadium deutlich schneller und bei geringerer Dehnung und weist eine geringere Kriechduktilität im Vergleich zu seinem konventionellen Gegenstück auf. Das Kriechschädigungsverhalten des AM-Werkstoffs ist eher mikrostruktur- als defektgesteuert und ist durch die Bildung intergranularer Kriechrisse gekennzeichnet. Als kritische Merkmale werden die Versetzungsdichte sowie die Versprödung der Korngrenzen identifiziert. Die Mikro-Computertomographie (µCT) erweist sich als Alternative zur Metallographie, um die Kriechschädigung zu analysieren. T2 - Sitzung des DGM-Arbeitskreises Mechanisches Werkstoffverhalten bei hoher Temperatur CY - Online meeting DA - 07.10.2020 KW - 316L KW - Kriechen KW - Additive Fertigung KW - Mikrostruktur KW - Mikro-Computertomographie PY - 2020 AN - OPUS4-51824 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sprengel, Maximilian T1 - Using Neutron Diffraction to Monitor Stress Relaxation in Additively Manufactured 316L N2 - The relaxation of residual stress in laser powder bed fused stainless steel 316L parts was monitored using monochromatic and time-of-flight neutron diffraction. T2 - ISIS student meeting CY - Online meeting DA - 26.10.2020 KW - Stainless Steel KW - Residual Stress KW - Additive Manufacturing PY - 2020 AN - OPUS4-51469 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ulbricht, Alexander A1 - Altenburg, Simon A1 - Sprengel, Maximilian A1 - Sommer, Konstantin A1 - Mohr, Gunther A1 - Fritsch, Tobias A1 - Mishurova, Tatiana A1 - Serrano-Munoz, Itziar A1 - Evans, Alexander A1 - Hofmann, M. A1 - Bruno, Giovanni T1 - Separation of the Formation Mechanisms of Residual Stresses in LPBF 316L N2 - Rapid cooling rates and steep temperature gradients are characteristic of additively manufactured parts and important factors for the residual stress formation. This study examined the influence of heat accumulation on the distribution of residual stress in two prisms produced by Laser Powder Bed Fusion (LPBF) of austenitic stainless steel 316L. The layers of the prisms were exposed using two different border fill scan strategies: one scanned from the centre to the perimeter and the other from the perimeter to the centre. The goal was to reveal the effect of different heat inputs on samples featuring the same solidification shrinkage. Residual stress was characterised in one plane perpendicular to the building direction at the mid height using Neutron and Lab X-ray diffraction. Thermography data obtained during the build process were analysed in order to correlate the cooling rates and apparent surface temperatures with the residual stress results. Optical microscopy and micro computed tomography were used to correlate defect populations with the residual stress distribution. The two scanning strategies led to residual stress distributions that were typical for additively manufactured components: compressive stresses in the bulk and tensile stresses at the surface. However, due to the different heat accumulation, the maximum residual stress levels differed. We concluded that solidification shrinkage plays a major role in determining the shape of the residual stress distribution, while the temperature gradient mechanism appears to determine the magnitude of peak residual stresses. KW - Additive Manufacturing KW - Laser Powder Bed Fusion KW - LPBF KW - AISI 316L KW - Online Process Monitoring KW - Thermography KW - Residual Stress KW - Neutron Diffraction KW - X-ray Diffraction KW - Computed Tomography PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512903 DO - https://doi.org/10.3390/met10091234 VL - 10 IS - 9 PB - MDPI CY - Basel AN - OPUS4-51290 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ávila Calderón, Luis A1 - Graf, B. A1 - Rehmer, Birgit A1 - Petrat, T. A1 - Skrotzki, Birgit A1 - Rethmeier, Michael T1 - Characterization of Ti-6Al-4V fabricated by multilayer laser powder-based directed energy deposition N2 - Laser powder-based directed energy deposition (DED-L) is increasingly being used in additive manufacturing (AM). As AM technology, DED-L must consider specific challenges. It must achieve uniform volume growth over hundreds of layers and avoid heat buildup of the deposited material. Herein, Ti–6Al–4V is fabricated using an approach that addresses these challenges and is relevant in terms of transferability to DED–L applications in AM. The assessment of the obtained properties and the discussion of their relationship to the process conditions and resulting microstructure are presented. The quality of the manufacturing process is proven in terms of the reproducibility of properties between individual blanks and with respect to the building height. The characterization demonstrates that excellent mechanical properties are achieved at room temperature and at 400 °C. KW - AGIL KW - Laser powder-based directed energy deposition KW - Tensile properties KW - Ti-6Al-4V KW - Microstructure PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542262 DO - https://doi.org/10.1002/adem.202101333 SN - 1438-1656 SN - 1527-2648 SP - 1 EP - 15 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54226 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ávila Calderón, Luis T1 - Creep and fracture behavior of conventionally and additively manufactured stainless steel 316L N2 - A critical task within the frame of establishing process-structure-property-performance relationships in additive manufacturing (AM) of metals is producing reliable and well-documented material behavior’s data and knowledge regarding the structure-property correlation, including the role of defects. After all, it represents the basis for developing more targeted process optimizations and more reliable predictions of performance in the future. Within this context, this contribution aims to close the actual gap of limited historical data and knowledge concerning the creep behavior of the widely used austenitic stainless steel 316L, manufactured by Laser-Powder-Bed-Fusion (L-PBF). To address this objective, specimens from conventional hot-rolled and AM material were tested under application-relevant conditions according to existing standards for conventional material, and microstructurally characterized before and after failure. The test specimens were machined from single blocks from the AM material. The blocks were manufactured using a standard scan and build-up strategy and were subsequently heat-treated. The creep behavior is described and comparatively assessed based on the creep lifetime and selected creep curves and characteristic values. The effect of defects and microstructure on the material’s behavior is analyzed based on destructive and non-destructive evaluations on selected specimens. The AM material shows shorter creep lives, reaches the secondary creep stage much faster and at a lower strain, and features lower creep ductility compared to its conventional counterpart. The creep damage behavior of the AM material is more microstructure than defect controlled and is characterized by the formation and accumulation of single intergranular damage along the whole volume. Critical features identified are the grain morphology and the grain-boundary as well as the dislocation’s density. Micro-computed tomography (µCT) proves to be an alternative to metallography to analyze the creep damage. T2 - ASTM International Conference on Additive Manufacturing 2020 CY - Online meeting DA - 16.11.2020 KW - 316L KW - Creep behavior KW - Laser powder bed fusion KW - Additive manufacturing KW - Microstructure PY - 2020 AN - OPUS4-51823 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ávila Calderón, Luis T1 - Assessing the low cycle fatigue behaviour of additively manufactured Ti-6Al-4V: Challenges and first results N2 - The understanding of process-microstructure-property-performance (PMPP) relationships in additive manufacturing (AM) of metals is highly necessary to achieve wide-spread industrial application and replace conventionally manufactured parts, especially regarding safety-relevant applications. To achieve this understanding, reliable data and knowledge regarding material’s microstructure-property relationships (e.g. the role of defects) is needed, since it represents the base for future more targeted process optimizations and more reliable calculations of performance. However, producing reliable material data and assessing the AM material behaviour is not an easy task: big challenges are e.g. the actual lack of standard testing methods for AM materials and the occasional difficulties in finding one-to-one comparable material data for the conventional counterpart. This work aims to contribute to end this lack of reliable material data and knowledge for the low cycle fatigue behaviour of the most used titanium alloy in aerospace applications (Ti-6Al-4V). For this purpose, two sets of test specimens were investigated. The first set was manufactured from cylindrical rods produced by an optimized DED-L process and the second was manufactured from a hot formed round bar. The test specimens were cyclically loaded until failure in the low-cycle-fatigue (LCF) regime. The tests were carried out according to ISO 12106 between 0.3 to 1.0 % axial strain amplitude from room temperature up to 400°C. The LCF behaviour is described and compared between materials and with literature values based on cyclic deformation curves and strain-based fatigue life curves. Besides, the parameters of Manson-Coffin-Basquin relationship were calculated. The microstructures (initial and after failure) and fracture surfaces were comparative characterized. Thereby, the focus lied on understanding the role of grain morphology and defects on the failure mechanisms and fatigue lifetimes. For this latter characterization, optical microscopy (OM), scanning electron microscopy (SEM) and micro computed tomography (µCT) were used. T2 - 4th International Symposium on Fatigue Design and Material Defects CY - Online meeting DA - 26.05.2020 KW - Ti-6Al-4V KW - Additive manufacturing KW - Low cycle fatigue KW - Micro computed tomography KW - Microstructure PY - 2020 AN - OPUS4-50893 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pittner, Andreas T1 - Wire arc additive manufacturing of high strength AL-MG-SI alloys N2 - Gas metal arc-based direct energy deposition (DED) additive manufacturing technologies hold significant promise for producing large-scale metal components. However, determining optimal process parameters to achieve the desired near-net shape design and mechanical performance is a complex challenge due to the intricate interplay between process parameters and material properties. This presentation highlights the use of a newly developed solid welding wire doped with TiB to improve grain refinement in metals deposited via DED-Arc for high-strength precipitation-hardening AlMgSi aluminum alloys. This wire stems from our initial metallurgical investigations into grain refinement in aluminum weld metals. The research emphasizes the relationship between process parameters and component quality, aiming to uncover the mechanisms that influence performance. This is essential for establishing a reliable range of parameters that meet quality standards, many of which are derived from traditional welding practices. Component quality was assessed by studying pore size, pore distribution, and grain morphology. To further enhance the mechanical properties of the deposited material, post-weld heat treatments—including solution treatment, quenching, and artificial aging—were applied. The study also explores how different heat treatment strategies affect the final mechanical properties. To validate the feasibility of 3D printing high-strength aluminum alloys, a more complex demonstrator component was fabricated. The results demonstrate that DED-Arc technology can produce large aluminum parts with a quality comparable to subtractive manufacturing techniques. Furthermore, the entire additive manufacturing workflow has been digitally integrated, enabling full traceability of all key process steps. This digital integration is critical for ensuring reliable quality assessments of the finished components. T2 - 77th IIW Annual Assembly and International Conference Joint Meeting of C-I, C-IV, and C-XII CY - Rhodos, Greece DA - 07.07.2024 KW - DED-Arc KW - High-strength aluminium alloys KW - Porosity assessment KW - Component testing KW - CT-analyses PY - 2024 AN - OPUS4-62014 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pittner, Andreas T1 - Additive Manufacturing of High Strength Al-Mg-Si Alloys with DED-Arc N2 - Direct energy deposition additive manufacturing technologies that utilize an electric arc have great potential for generating large volume metal components. However, selecting process parameters that yield the desired near net shape design and requested mechanical component behavior is not a trivial task due to the complex relationship between all process parameters and material characteristics. This presentation exemplifies the application of a newly developed solid welding wire doped with TiB to enhance grain refinement in the deposited metal for additive manufacturing based on DED-Arc of high-strength precipitation hardening AlMgSi-aluminum alloys. It is worth noting that the solid wire is the result of our preliminary metallurgical studies on grain refinement in aluminum weld metal. Consequently, research focuses on the correlation between process parameters and component quality to understand the underlying mechanisms. This is crucial for evaluating a robust process parameter space that yields component quality in line with corresponding standards which are mainly taken from welding technology. Specifically, we examine component quality by analyzing pore size and distribution, as well as grain morphology. To enhance the mechanical properties of the deposited metal, a post-weld heat treatment was conducted, comprising of solution treatment, quenching, and artificial aging. The study also evaluates the effects of various heat treatment strategies on the final mechanical properties of the material. To demonstrate the applicability of 3D metal printing of high-strength aluminium alloys, a more complex demonstrator was created. It has been shown that DED-Arc can produce high-volume aluminium parts with the same quality as the corresponding subtractive processing strategy. Additionally, the entire additive manufacturing chain has been digitally integrated, enabling traceability of all relevant process steps, which is essential for reliable subsequent quality assessment. T2 - 4th Symposium on Materials and Additive Manufacturing - Additive 2024 CY - Berlin, Germany DA - 12.06.2024 KW - DED-Arc KW - High-stength aluminium alloys KW - Grain refinement KW - Quality assurance PY - 2024 AN - OPUS4-60248 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Marquardt, R. A1 - Gook, S. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Handgeführtes Laserstrahlschweissen am T-Stoss eines niedrig legierten Stahls N2 - Das handgeführte Laserstrahlschweißen gewinnt in der Industrie zunehmend an Bedeutung, da die hohe Produktivität und die einfache Handhabung Unternehmen wirtschaftliche Vorteile bieten. Derzeit ist der Einsatz in der Industrie jedoch auf Teile mit ästhetischen Anforderungen beschränkt, die häufig aus hochlegiertem Stahl bestehen. Um das Handschweißen mit Laserstrahl auch für Bauteile aus kostengünstigen Stähle mit guten mechanischen Eigenschaften einsetzen zu können, untersucht diese Studie den Einfluss des Schutzgases auf die Porosität am mikrolegierten Stahl HX340LAD mit einer Dicke von 1,5 mm. Getestet wurden die Gase Argon, Stickstoff, CO2 sowie Mischungen aus Argon und CO2 an T-Stöße mit Zusatzdraht. Die Qualifizierung der Porosität erfolgte gemäß DIN EN ISO 13919-1 an Querschliffen als auch mittels Röntgenuntersuchung. Die Ergebnisse zeigen, dass für diesen Stahl die Bewertungsgruppe B mittels CO2 als Schutzgas erreicht werden kann. Stickstoff führt zu Gruppe C, Argon zu D. KW - Handgeführtes Laserstrahlschweißen, HHLW, Stahl, Laser KW - HHLW KW - Stahl KW - Laser PY - 2025 SP - 22 EP - 25 PB - Schweizerischer Verein für Schweisstechnik SVS AN - OPUS4-65041 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Vinzenz A1 - Fasselt, Janek Maria A1 - Klötzer-Freese, Christian A1 - Kruse, Tobias A1 - Kleba-Ehrhardt, Rafael A1 - Biegler, Max A1 - Rethmeier, Michael T1 - Recycling nickel aluminium bronze grinding chips to feedstock for directed energy deposition via impact whirl milling: Investigation on processability, microstructure and mechanical properties N2 - During the production of ship propellers, considerable quantities of grinding chips from nickel aluminium bronze areproduced. This paper examines the mechanical comminution of such chips via impact whirl milling and the utilization of twochip-powder batches as feedstock for a laser-based directed energy deposition process. The materials are characterized viadigital image analysis, standardized flowability tests, scanning electron microscopy and energy dispersive X-ray spectroscopyand are compared to conventional, gas atomized powder. The specimens deposited via directed energy deposition areanalyzed for density, hardness and microstructure and tensile properties for vertical and horizontal build up directions arecompared. At elevated mill rotation speeds, the comminution with impact whirl milling produced rounded particles, favorableflow properties and particle size distribution, making them suitable to deposit additive specimens. The microstructureexhibited characteristic martensitic phases due to the high cooling rates of the additive manufacturing process. The presenceof ceramic inclusions was observed in both the powder and on the tensile fracture surfaces, partly impairing the mechanicalproperties. However, specimens in the vertical build-up direction (Z) showed competitive tensile results, with 775 MPa intensile strength, 455 MPa in yield strength and 12.6 % elongation at break. The findings of this study indicate that recyclingof machining chips to additive manufacturing feedstock can be a viable option for reducing material costs and environmentalimpact. KW - Nickel aluminium bronze KW - Grinding chips KW - Recycling KW - Directed energy deposition KW - Material characterization PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651214 DO - https://doi.org/10.1016/j.addma.2025.104804 SN - 2214-8604 VL - 105 SP - 1 EP - 9 PB - Elsevier B.V. AN - OPUS4-65121 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lemke, J. T1 - Water and gas atomized AISI 316L powder for DED-LB: A comparative study on powder properties and build quality N2 - Powder properties are considered a key factor in part quality in laser additive manufacturing, although few studies have investigated the effects in directed energy deposition (DED). Water atomized (WA) and gas atomized (GA) powders are frequently used but may result in different part properties due to powder properties. To examine their qualification for DED-LB, this work examines powders and build quality of AISI 316L. Also, examination techniques are compared. The results show that the powder production has no relevant influence on porosity and Archimedian density of built parts. WA powders show good processability in DED-LB, despite unfavorable morphology. In contrast, WA specimen reach only 10% fracture elongation in tensile testing whereas GA-based specimen achieve 30%. Tensile strength of both is above 500 MPa. The reason for the lower mechanical property values can be attributed to defects and oxides. WA powders may provide a cost-effective alternative for DED-LB when mechanical load requirements are not important. T2 - Lasers in Manufacturing Conference CY - Munich, Germany DA - 23.06.2025 KW - DED-LB KW - Porosity KW - AISI 316L KW - Water atomized KW - Gas atomized KW - Powder PY - 2025 AN - OPUS4-65120 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Chaurasia, Prashant Kumar A1 - Cagtay, Fabry A1 - Andreas, Pittner 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. T2 - IIW Annual Assembly 2025 CY - Genova, Italy DA - 23.06.2025 KW - Additive Manufacturing KW - Arc welding KW - Real-time monitoring and control KW - Dimensional inconsistency KW - DED-arc PY - 2025 AN - OPUS4-65231 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -