Univ. Prof. Dr. Ing.

Bergs, Thomas

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  • Publication
    Determination of the Level of Automation for Additive Manufacturing Process Chains
    ( 2021)
    Horstkotte, Rainer
    ;
    Bruning, Benedikt
    ;
    Prümmer, Marcel
    ;
    Arntz, Kristian
    ;
    Bergs, Thomas
    Industrial manufacturing is confronted with increased cost pressure due to international competition. The use of automation solutions can help to optimally exploit existing potentials and react to market competitors. In particular, increased productivity and shorter cycle times lead to reduced costs and increased capabilities. New manufacturing technologies can also help to achieve an advantage over market competitors. In recent years, additive manufacturing technologies in particular have gained in importance. Laser Powder Bed Fusion (L-PBF) is an additive manufacturing (AM) technology that enables the production of highly complex and individualized metal components. A significant disadvantage of L-PBF is the required post-processing of additive manufactured parts, which is necessary to remove auxiliary structures, separate the workpieces from the substrate plate and obtain high precision as well as low surface roughness. Automation of these post-processes is a crucial factor for increasing productivity and thus for further industrialization of L-PBF. In order to exploit this potential optimally, the level of automation has to be determined. In this paper, a methodology is presented that enables the determination of the level of automation for the additive process chain with L-BPF. The focus is on evaluating the level of automation of individual manufacturing technologies due to consideration of technology-specific requirements and characteristics. The scope of the analysis is not limited to technologies; handling processes are also taken into account. A differentiated e valuation of the level of automation is enabled by the definition of technology-specific and cross-technology sub-tasks.
  • Publication
    Generation and evaluation of automation concepts of additive process chains with Laser Powder Bed Fusion (L-PBF)
    ( 2021)
    Horstkotte, Rainer
    ;
    Heinrich, Florian
    ;
    Prümmer, Marcel
    ;
    Arntz, Kristian
    ;
    Bergs, Thomas
    Laser Powder Bed Fusion (L-PBF) is an additive manufacturing (AM) technology that plays a major role in the production of mass customized metal components and products. A significant disadvantage of AM is the required post-processing of the additive manufactured parts, which is necessary to remove auxiliary structures, separate the workpieces from the substrate plate and achieve high precision as well as low surface roughness. Automation of these post-processes is a crucial factor for increasing productivity and thus for further industrialization of L-PBF. This paper presents a methodology to model and evaluate the manufacturing process chain of post-processing with regard to automation. For this purpose, a uniform notation is introduced to model the sequence of manufacturing processes and handling operations. The notation allows the representation of different automation concepts and integrates typical post-processes for L-PBF manufactured parts. A reference scale is used to evaluate different concepts with regard to their level of automation. The focus on lead time estimation enables the methodology to generate and evaluate different automation concepts.
  • Publication
    Reflectometry-based investigation of temperature fields during dual-beam Laser Metal Deposition
    ( 2021)
    Gipperich, Marius
    ;
    Peters, Christian
    ;
    Riepe, Jan
    ;
    Day, Robin
    ;
    Bergs, Thomas
    Laser Metal Deposition (LMD) is a high deposition rate metal Additive Manufacturing process. Its applications are basically repair, cladding and manufacturing. The two most commonly used LMD processes are powder-based (LMD-p) and wire-based (LMD-w). Despite the fact that wire-based LMD is more material efficient, process stability is a major concern. By adding a modulated laser beam to the continuous process beam, a change of the melt pool geometry and increased energy absorption are observed. This relation shows great potential to increase process stability. In this contribution, the positive effect of the dual laser-beam use on LMD-w processes is demonstrated. To understand the cause-effect relation, the workpiece temperature field was investigated by optical backscatter reflectometry ( OBR). The results were then correlated to simultaneously performed IR camera measurements of the workpieces upper surface. By better understanding the thermal phenomena in dual-beam LMD, research can improve process temperature control. This leads to a new perspective for the LMD-w manufacturing process in many industry sectors such as mobility, energy and engineering.
  • Publication
    Development of handling system concepts for additive process chains with Laser Powder Bed Fusion (L-PBF)
    ( 2021)
    Horstkotte, Rainer
    ;
    Heinrich, Florian
    ;
    Prümmer, Marcel
    ;
    Arntz, Kristian
    ;
    Bergs, Thomas
    Laser Powder Bed Fusion (L-PBF) is an additive manufacturing (AM) technology that enables the production of highly complex and individualized metal components. Since these components need post-processing, L-PBF is usually utilized within a manufacturing process chain. The automation of this process chain is a crucial step towards the industrialization of L-PBF. This paper presents a methodology for the conceptual design of handling systems for the automated handling of L-PBF components. It includes the selection of gripping and clamping devices, robots and other peripheral systems. Restrictions that arise from the complexity of the components and the technologies are considered.
  • Publication
    Lebensdauerverlängerung von Eisenbahnrädern durch Laserauftragschweißen mit Draht
    ( 2020)
    Shamshoom, Jeries
    ;
    Gipperich, Marius
    ;
    Huberty, Benoît
    ;
    Schindler, Christian
    ;
    Bergs, Thomas
    Heutzutage werden Eisenbahnräder durch maschinelle Bearbeitung neu profiliert, wenn dies aufgrund von Verschleiß oder Flachstellen erforderlich wird. Das damit verbundene Verfahren besteht aus mehreren Schritten und ist daher zeitaufwändig und kostenintensiv. Aus diesem Grund kann ein auf dem Auftragschweißen basierendes Reparatur- und Herstellungsverfahren vorteilhaft sein. In diesem Beitrag werden die Eignung des Laserauftragschweißens mit Draht (LMD-w) als Technologie für diese Anwendung analysiert und weitere Entwicklungsschritte diskutiert.
  • Publication
    Durchgängige Bearbeitung von 3D-gedruckten Metallteilen
    ( 2020)
    Wollbrink, Moritz
    ;
    Maslo, Semir
    ;
    Arntz, Kristian
    ;
    Bergs, Thomas
    Der Fertigungsanteil der additiven Fertigung (AM) und besonders des pulverbettbasierten Laserstrahlschmelzens (L-PBF) nimmt in der industriellen Anwendung weiter zu. Allein mit AM lassen sich jedoch oft keine engen Maßtoleranzen oder geringen Oberflächenrauheiten erzielen. Daher muss eine Prozesskette generiert werden, die die additive Fertigung mit weiteren Bearbeitungstechnologien kombiniert. Um einen kontinuierlichen Werkstückfluss als Basis für die weitere Industrialisierung von L-PBF zu erreichen, wird ein neuartiges Substratplattensystem sowie dessen Anwendung in L-PBF-Maschinen und bei der Weiterbearbeitung vorgestellt. Das Substratplattensystem besteht aus einem Nullpunkt-Spannsystem und matrixartig angeordneten Verbindungsstiften, welche die werkstückseitige Verbindung sehr flexibel ermöglichen.
  • Publication
    Tailored melt pool shape and temperature distribution by a dual laser beam LMD-w process
    ( 2020)
    Gipperich, Marius
    ;
    Riepe, Jan
    ;
    Day, Robin
    ;
    Bergs, Thomas
    Laser Metal Deposition (LMD) is a high deposition rate metal AM process used for repair, cladding or manufacturing. While wire-based LMD (LMD-w) offers several advantages such as high material efficiency and a safe and simple handling of the wire feedstock, advanced concepts are needed to increase the LMD-w process stability. In this presentation, an approach is investigated to stabilize the LMD-w process by combining a continuous wave (cw) laser and a low-power pulsed wave (pw) laser. Calorimeter-like absorption measurements as well as deposition experiments are carried out to understand the physical background of the dual laser process and how this setup helps to stabilize the process. Promising results were achieved showing the possibility to tailor the melt pool height and width by a factor of 1.5-2 and an increase of energy absorption by 20 %. This offers new perspectives for the LMD-w manufacturing process in many industry sectors.
  • Publication
    Methodology for Integration of Additive Manufacturing in Tool Manufacturing Process Chains
    ( 2019)
    Bergs, Thomas
    ;
    Arntz, Kristian
    ;
    Wollbrink, Moritz
    In the past years, additive manufacturing (AM) enriched the tool manufacturing with a group of new technologies. This implicates two action fields for tooling industry. 1) Toolmaking companies are experts for precision manufacturing of complex metal components. Regarding AM technologies, which do not reach typical tolerances for toolmaking, the imperative is to integrate AM in process chains. 2) Toolmaking is one of a kind production. Hence, toolmaking companies are equipped with manufacturing and planning systems to handle individual components. 1) and 2) indicate the eligibility for the integration of AM. The paper points out an approach of the integration of AM technologies in an existing machinery. It explains the stepwise procedure of status quo machinery analysis, machinery performance evaluation, workpiece identification and process chain development. The machinery analysis incudes i.a. an overview of available technologies and knowledge and a gap analysis to available technologies on the market. Machinery performance is compared to database data (Fraunhofer IPT has an extensive database of toolmakers machinery performance) to classify the companys equipment. The workpiece identification is based on dominant workpiece features, which determine a group of technological possible manufacturing technologies. Based on, an integrated AM process chain can be created.