TY - CONF A1 - Graf, B. T1 - 3D laser metal deposition in an additive manufacturing process chain N2 - Laser metal deposition is described with its applications for additive manufacturing. The necessary process chain is discussed, with regard to weld bead dimensions and 3D build-up strategy. Metallurgical cross sections, x-ray and tensile tests are conducted. As demonstrative components, a gas turbine burner and a turbine blade are shown T2 - 1st International Congress on Welding, Additive Manufacturing and Associated Non-Destructive Testing CY - Metz, France DA - 17.05.2017 KW - Additive manufacturing KW - Ti-6Al-4V KW - Process chain KW - Turbine industry KW - Laser metal deposition PY - 2017 AN - OPUS4-44477 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Graf, B. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - 3D laser metal deposition in an additive manufacturing process chain N2 - Laser metal deposition is described with its applications for additive manufacturing. The necessary process chain is discussed, with regard to weld bead dimensions and 3D build-up strategy. Metallurgical cross sections, x-ray and tensile tests are conducted. As demonstrative components, a gas turbine burner and a turbine blade are shown. T2 - 1st International Congress on Welding, Additive Manufacturing and Associated Non- CY - Metz, France DA - 17.05.2017 KW - Laser metal deposition KW - Additive manufacturing KW - Ti-6Al-4V KW - Turbine industry KW - Process chain PY - 2017 UR - https://icwam.com/sites/default/files/Abstract%20book.pdf SP - AM 34-2 EP - 3 AN - OPUS4-43190 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai T1 - Build-up strategies for additive manufacturing of three-dimensional Ti-6Al-4V-parts produced by Laser Metal Deposition N2 - Laser metal deposition (LMD) has been applied as coating technology for many years. Today, the technologies capacity to produce 3D depositions leads to a new field of application as additive manufacturing method. In this paper, 3D laser metal deposition of titanium alloy Ti-6Al-4V is studied with special regard to the demands of additive manufacturing. Therefore, only the powder nozzle is used to create the shielding gas atmosphere, which ensures high geometric flexibility. Furthermore, specimen with high aspect ratio and hundreds of layers are manufactured, which represent typical features in additive manufacturing. T2 - ICALEO CY - Atlanta, USA DA - 22.10.2017 KW - Additive manufacturing KW - Ti-6Al-4V KW - Laser Metal Deposition PY - 2017 AN - OPUS4-42865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Marko, A. A1 - Graf, B. A1 - Rethmeier, Michael T1 - Statistical analysis of weld bead geometry in Ti6Al4V laser cladding N2 - The process of laser cladding has become more important during recent years because of its broad application for cladding, repair or additive manufacturing. In the field of mechanical engineering, one use is the repair of turbine blades. For high quality and reliability of the repaired components, it is necessary to adjust the weld bead geometry to the specific repair task. The bead geometry influences the metallurgical bonding and the degree of dilution as well as the formation of defects like pores or cracks. Therefore, it is important to know the effects of the different parameters on the welding bead. A valuable tool to meet this industrial challenge is the design of experiments (DoE). In this context, the user can choose between a huge number of test plans. Greater Profit of information is expected by a larger test range. In order to confirm the acceptance, a five-step full factorial test plan is compared to a central composite design in this paper. Moreover, the limits of the experimental range are indicated and restrictions can be derived. As the results show, the essential effects are detected with a full factorial test plan as well as with a central composite design. Merely the effect strength could not always be specified unambiguously. On this account and in consideration of cost efficiency, the use of central compound design is recommended in industrial applications. KW - Laser metal deposition KW - Design of experiments KW - Laser cladding KW - Cladding parameter KW - Additive manufacturing PY - 2017 DO - https://doi.org/10.3139/120.111077 SN - 0025-5300 SN - 2195-8572 VL - 59 IS - 10 SP - 837 EP - 843 PB - Carl Hanser Verlag CY - München AN - OPUS4-42882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenberg, Rainer A1 - Charmi, Amir T1 - Virtual-lab-based determination of a macroscopic yield function for additively manufactured parts N2 - This work presents a method for the yield function determination of additively manufactured parts of S316L steel. A crystal plasticity model is calibrated with test results and used afterwards to perform so-called virtual experiments, that account for the specific process-related microstructure including crystallographic and morphological textures. These simulations are undertaken on a representative volume element (RVE), that is generated from EBSD/CT-Scans on in-house additively manufactured specimen, considering grain structure and crystal orientations. The results of the virtual experiments are used to determine an anisotropic Barlat yield function, that can be used in a macroscopical continuum-sense afterwards. This scale-bridging approach enables the calculation of large-scale parts, that would be numerically too expensive to be simulated by a crystal plasticity model. T2 - 3. Tagung des DVM-Arbeitskreises Additiv gefertigte Bauteile und Strukturen CY - Berlin, Germany DA - 07.11.2018 KW - Virtual experiments KW - Additive manufacturing KW - Anisotropy KW - Crystal plasticity KW - Scale-bridging PY - 2018 AN - OPUS4-46895 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pfretzschner, Beate T1 - Characterization of texture in SLM IN 718 samples using monochromatic neutron radiography N2 - Additive Manufacturing (AM) offers the opportunity to produce easier geometrically complex parts compared to traditional production technologies. An important AM technology for metals is selective laser melting (SLM) where a part is produced by melting and solidifying powder in layers. This technique is known to cause a pronounced texture in the produced AM products due to the specific heat flow and the associated solidification of the material during SLM deposition. In order to evaluate the influence of the deposition hatch length during SLM of nickel based superalloy Inconel 718 samples on the texture and in order to identify any preferred crystallographic direction, we performed monochromatic neutron radiography scans (using wavelength from 1.6 Å to 4.4 Å, step size 0.05 Å) to image the samples while rotating it through 90°. Samples produced with short hatch length showed fine textured columnar grains oriented along the sample building direction in high-resolution radiographs. Whereas processing the sample using a ten-fold longer hatch length reduced the texture. The neutron radiographic experiments were accompanied by scanning electron microscopy including electron back-scattered diffraction to visualize and verify the microstructure and texture. T2 - German Conference for Research with Synchrotron Radiation, Neutrons and Ion Beams at Large Facilities CY - Garching, Germany DA - 17.09.2018 KW - Bragg-edge KW - Neutron KW - Texture KW - Additive manufacturing PY - 2018 AN - OPUS4-47260 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sommer, Konstantin T1 - Microstructure characterization of additive produced parts N2 - Due to the advantages of additive manufacturing (AM), it has been increasingly integrated into many industrial sectors. The application of AM materials for safety-critical parts requires the detailed knowledge about their microstructure stability under thermo-mechanical or mechanical load and knowledge on ageing process mechanisms. Ageing processes are characterized by change of the material microstructure that is to be initially investigated. This work deals with the Investigation of 316L stainless steel manufactured by selective laser melting (SLM). Describing Parameters must be defined and applied on the microstructure of these materials in their initial state and after loads were applied. The findings of this work form the basis for the investigation of AM material ageing. T2 - FEMS Junior EUROMAT 2018 CY - Budapest, Hungary DA - 08.07.2018 KW - Additive manufacturing KW - Selective laser melting KW - 316L KW - Material characterization KW - Microstructure PY - 2018 AN - OPUS4-47176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Biegler, P. ED - Marko, A. ED - Graf, B. ED - Rethmeier, Michael T1 - Finite element analysis of in-situ distortion and bulging for an arbitrarily curved additive manufacturing directed energy deposition geometry N2 - With the recent rise in the demand for additive manufacturing (AM), the need for reliable simulation tools to support experimental efforts grows steadily. Computational welding mechanics approaches can simulate the AM processes but are generally not validated for AM-specific effects originating from multiple heating and cooling cycles. To increase confidence in the outcomes and to use numerical simulation reliably, the result quality Needs to be validated against experiments for in-situ and post-process cases. In this article, a validation is demonstrated for a structural thermomechanical simulation model on an arbitrarily curved Directed Energy Deposition (DED)part: at first, the validity of the heat input is ensured and subsequently, the model’s predictive quality for in-situ deformation and the bulging behaviour is investigated. For the in-situ deformations, 3D-Digital Image Correlation measurements are conducted that quantify periodic expansion and shrinkage as they occur. The results show a strong dependency of the local stiffness of the surrounding geometry. The numerical Simulation model is set up in accordance with the experiment and can reproduce the measured 3-dimensional in-situ displacements. Furthermore, the deformations due to removal from the substrate are quantified via 3D-scanning, exhibiting considerable distortions due to stress relaxation. Finally, the prediction of the deformed shape is discussed in regards to bulging simulation: to improve the accuracy of the calculated final shape, a novel Extension of the model relying on the modified stiffness of inactive upper layers is proposed and the experimentally observed bulging could be reproduced in the finite element model. KW - DED KW - Welding simulation KW - Additive manufacturing KW - Dimensional accuracy KW - Digital image correlation PY - 2018 DO - https://doi.org/10.1016/j.addma.2018.10.006 SN - 2214-8604 SN - 2214-7810 VL - 24 SP - 264 EP - 272 PB - Elsevier AN - OPUS4-47226 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spranger, Felix A1 - Graf, B. A1 - Schuch, M. A1 - Hilgenberg, Kai A1 - Rethmeier, Michael T1 - Build-up strategies for additive manufacturing of three dimensional Ti-6Al-4V-parts produced by laser metal deposition N2 - Laser metal deposition (LMD) has been applied as a coating technology for many years. Today, the technologies capacity to produce 3D depositions leads to a new field of application as additive manufacturing method. In this paper, 3D laser metal deposition of titanium alloy Ti-6Al-4V is studied with special regard to the demands of additive manufacturing. Therefore, only the coaxial LMD powder nozzle is used to create the shielding gas atmosphere, which ensures high geometric flexibility. Furthermore, specimen with high aspect ratio and hundreds of layers are manufactured, which represent typical features in additive manufacturing. The presented study contains the following steps: First, cylindrical specimens are manufactured with a standard shell-core build-up strategy and mechanical properties as well as fracture mechanisms are determined. Based on the results, experiments are conducted to improve the build-up strategy and new tensile test specimens are built with the improved strategy. The improved strategy incorporates variable track overlap ratios to achieve a constant growth in the shell and core area. As blanks, lean cylinders comprising more than 240 layers and a height of more than 120mm are manufactured. The specimens are analyzed by X-ray inspection for material defects. Fractured surfaces are observed via scanning electron microscopy and the composition of the surfaces is determined using energy dispersive X-ray spectroscopy. The tensile test results prove mechanical properties close to ASTM F1108 specification for wrought material. KW - Laser metal deposition KW - Ti-6Al-4V KW - Additive manufacturing KW - Titanium alloy KW - Turbine components PY - 2018 DO - https://doi.org/10.2351/1.4997852 SN - 1938-1387 SN - 1042-346X VL - 30 IS - 2 SP - UNSP 022001, 1 EP - 13 PB - Laser Institute of America AN - OPUS4-44655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Graf, B. A1 - Marko, A. A1 - Petrat, T. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - 3D laser metal deposition: process steps for additive manufacturing N2 - Laser metal deposition (LMD) is an established technology for two-dimensional surface coatings. It offers high deposition rates, high material flexibility, and the possibility to deposit material on existing components. Due to these features, LMD has been increasingly applied for additive manufacturing of 3D structures in recent years. Compared to previous coating applications, additive manufacturing of 3D structures leads to new challenges regarding LMD process knowledge. In this paper, the process steps for LMD as additive manufacturing technology are described. The experiments are conducted using titanium alloy Ti-6Al-4Vand Inconel 718. Only the LMD nozzle is used to create a shielding gas atmosphere. This ensures the high geometric flexibility needed for additive manufacturing, although issues with the restricted size and quality of the shielding gas atmosphere arise. In the first step, the influence of process parameters on the geometric dimensions of single weld beads is analyzed based on design of experiments. In the second step, a 3D build-up strategy for cylindrical specimen with high dimensional accuracy is described. Process parameters, travel paths, and cooling periods between layers are adjusted. Tensile tests show that mechanical properties in the as-deposited condition are close to wrought material. As practical example, the fir-tree root profile of a turbine blade is manufactured. The feasibility of LMD as additive technology is evaluated based on this component. KW - Laser metal deposition KW - Build-up strategy KW - Deposition rate KW - Additive manufacturing PY - 2018 DO - https://doi.org/10.1007/s40194-018-0590-x SN - 0043-2288 SN - 1878-6669 VL - 62 IS - 4 SP - 877 EP - 883 PB - Springer Berlin Heidelberg CY - Heidelberg AN - OPUS4-44868 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Metz, Christian A1 - Franz, Philipp A1 - Fischer, C. A1 - Wachtendorf, Volker A1 - Maierhofer, Christiane T1 - Active thermography for quality assurance of 3D-printed polymer structures N2 - Additively manufactured test specimens made of polyamide 12 (PA 12) by Laser Sintering (LS) as well as of acrylnitril-butadien-styrol (ABS) by Fused Layer Modeling (FLM), were tested with active thermography. For this, two different excitation methods (flash and impulse excitation) were used and compared, regarding the suitability for the detection of constructed and imprinted defects. To increase the quality of the thermograms, data processing methods like thermal signal reconstruction (TSR) and Fourier-Transformation were applied. Furthermore, the long-term stability of the probes towards environmental stress, like UV-radiation, heat, water contact and frost is being investigated in the presented project with artificial weathering tests. T2 - 14th Quantitative InfraRed Thermography Conference CY - Berlin, Germany DA - 25.06.2018 KW - Additive manufacturing KW - Active thermography KW - Artificial weathering PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453919 SP - Tu.3.A.2, 1 EP - 9 AN - OPUS4-45391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Metz, Christian A1 - Franz, Philipp A1 - Wachtendorf, Volker A1 - Maierhofer, Christiane A1 - Fischer, C. ED - Ziegahn, K.-F. T1 - Additiv gefertigte Polymerbauteile: Untersuchung der Beständigkeit durch künstliche Bewitterung und zerstörungsfreie Charakterisierung N2 - Es wird ein Verfahren zur Charakterisierung der Beständigkeit und Langzeitstabilität von additiv gefertigten Kunststoff-Bauteilen vorgestellt. Dabei sollen die Prüfkörper über 2000 Stunden künstlich bewittert und währenddessen die Änderungen der Eigenschaften der Bauteile zerstörungsfrei untersucht werden. T2 - 47. Jahrestagung der Gesellschaft für Umweltsimulation e.V. CY - Stutensee, Germany DA - 21.03.2018 KW - Additive Fertigung KW - Künstliche Bewitterung KW - Thermografie KW - Additive manufacturing PY - 2018 VL - 47. SP - 99 EP - 105 PB - Gesellschaft für Umweltsimulatin e.V. AN - OPUS4-44638 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenberg, Rainer A1 - Charmi, Amir T1 - Virtual-lab-based determination of a macroscopic yield function for additively manufactured parts N2 - Diese Arbeit beschreibt eine Methode für die Ermittlung einer Fließfunktion für additiv gefertigte Bauteile des Werkstoffs S316L. Ein Kristallplastizitätsmodell wird zunächst mit experimentellen Daten kalibriert. Anschließend werden mit diesem Modell sogenannte virtuelle Experimente durchgeführt, die die prozeßspezifische Mikrostruktur in Form von kristallographischen und morphologischen Texturen miteinbeziehen. Diese Simulationen werden mit einem representativen Volumenelement (RVE) durchgeführt, das aus EBSD/CT-Scans an additiv gefertigten Proben generiert wurde und daher die Kornstruktur und Kristallorientierungen enthält. Die virtuellen Experimente werden durchgeführt, um anhand der damit erhaltenen Fließpunkte eine anisotrope Barlat-Fließfunktion zu bestimmen. Dieser skalenübergreifende Ansatz ermöglicht die Simulation großer Strukturen, für die die Anwendung eines Kristallplastizitätsmodells numerisch zu teuer wäre. N2 - This work presents a method for the yield function determination of additively manufactured parts of S316L steel. A crystal plasticity model is calibrated with test results and used afterwards to perform so-called virtual experiments, that account for the specific process-related microstructure including crystallographic and morphological textures. These simulations are undertaken on a representative volume element (RVE), that is generated from EBSD/CT-Scans on in-house additively manufactured specimen, considering grain structure and crystal orientations. The results of the virtual experiments are used to determine an anisotropic Barlat yield function, that can be used in a macroscopical continuum-sense afterwards. This scale-bridging approach enables the calculation of large-scale parts, that would be numerically too expensive to be simulated by a crystal plasticity model. T2 - 3. Tagung des DVM-Arbeitskreises Additiv gefertigte Bauteile und Strukturen CY - Berlin, Germany DA - 07.11.2018 KW - Additive manufacturing KW - Scale-bridging KW - Crystal plasticity KW - Virtual experiments KW - Anisotropy PY - 2018 SN - 2509-8772 SP - 153 EP - 158 PB - DVM CY - Berlin AN - OPUS4-46570 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Blaeß, Carsten T1 - Binder jetting of crystallizing bioactive glass powders N2 - Customized artificial bone replacement implants made of resorbable bioactive glass (BG) have not yet become widely accepted in clinical use. This is mainly due to the contrariness of sintering ability and appropriate bioactivity. Concurrent crystallization often prevents the generation of dense sinter bodies, especially for additive manufactured 3D scaffolds. The presented study investigates the limits and advantages of crystallization of powder compacts manufactured by binder jetting and uniaxial pressing for different particle size fractions (psf) of two BGs. T2 - CeramicAM 2024 - 1º CY - Sao Paulo, Brasil DA - 19.09.2024 KW - Bioactive glass KW - Sintering KW - Crystallization KW - Additive manufacturing PY - 2024 AN - OPUS4-62594 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai T1 - EOS M300 as the heart of the QI living lab: Advancing with digital process chains N2 - This presentation shows how the connectivity of the EOS-M300/4 laser powder bed system is used to capture machine and process data as part of the living lab in QI Digital and how this can enable future digital quality assurance in additive manufacturing. T2 - AM Forum 2025 CY - Berlin, Germany DA - 17.03.2025 KW - Additive manufacturing KW - Quality assurance KW - QI Digital KW - Living lab PY - 2025 AN - OPUS4-62740 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Siefke, Lennart A1 - Linden, Anna T1 - Towards a robust automated surface inspection method for CT-scanned cannulas N2 - For certain cardiovascular diseases, cannulas are implanted into the blood circuit. To match the patients individual anatomy of the heart, there is research for cannulas to be custom-designed and manufactured aided by 3D printing. However, cannulas have to hold very high standards with regard to the smoothness of their surfaces, as rough patches can lead to formation of blood clots. Therefore, this work uses computer vision to detect such patches as part of quality assurance. First, the produced cannula is scanned using a precise CT scanner and transformed into a 3D mesh object. Rough patches in an otherwise smooth but curved surface are detected by using cosine similarity between neighboring faces and a statistical evaluation. In the end, this method is able to raise a warning when curved surfaces are not smooth enough and visualizes the problematic patches. However, there is just limited access to test data currently and the scanner used needs to be upgraded. T2 - 3D in Science & Applications (3D-iSA) 2024 CY - Berlin, Germany DA - 26.11.2024 KW - Algorithm KW - Additive manufacturing KW - Surface evaluation PY - 2025 UR - https://www.gfai.de SN - 978-3-942709-34-7 SP - 66 EP - 70 AN - OPUS4-63057 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Strobl, Dominic A1 - Unger, Jörg F. A1 - Ghnatios, C. A1 - Robens-Radermacher, Annika T1 - PGD in thermal transient problems with a moving heat source: A sensitivity study on factors affecting accuracy and efficiency N2 - Thermal transient problems, essential for modeling applications like welding and additive metal manufacturing, are characterized by a dynamic evolution of temperature. Accurately simulating these phenomena is often computationally expensive, thus limiting their applications, for example for model parameter estimation or online process control. Model order reduction, a solution to preserve the accuracy while reducing the computation time, is explored. This article addresses challenges in developing reduced order models using the proper generalized decomposition (PGD) for transient thermal problems with a specific treatment of the moving heat source within the reduced model. Factors affecting accuracy, convergence, and computational cost, such as discretization methods (finite element and finite difference), a dimensionless formulation, the size of the heat source, and the inclusion of material parameters as additional PGD variables are examined across progressively complex examples. The results demonstrate the influence of these factors on the PGD model’s performance and emphasize the importance of their consideration when implementing such models. For thermal example, it is demonstrated that a PGD model with a finite difference discretization in time, a dimensionless representation, a mapping for a moving heat source, and a spatial domain non-separation yields the best approximation to the full order model. KW - Additive manufacturing KW - Mapping for unseparable load KW - Model order reduction (MOR) KW - Thermal transient problem KW - Sensitivity analysis KW - Proper generalized decomposition (PGD) PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598001 DO - https://doi.org/10.1002/eng2.12887 VL - 6 IS - 11 SP - 1 EP - 22 PB - John Wiley & Sons Ltd. CY - Berlin AN - OPUS4-59800 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hildebrand, G. A1 - Sänger, Johanna Christiane A1 - Schirmer, U. A1 - Mantei, W. A1 - Dupuis, Y. A1 - Houbertz, R. A1 - Liefeith, K. T1 - Process Development for Additive Manufacturing of Alumina Toughened Zirconia for 3D Structures by Means of Two-Photon Absorption Technique N2 - Additive manufacturing is well established for plastics and metals, and it gets more and more implemented in a variety of industrial processes. Beside these well-established material platforms, additive manufacturing processes are highly interesting for ceramics, especially regarding resource conservation and for the production of complex three-dimensional shapes and structures with specific feature sizes in the µm and mm range with high accuracy. The usage of ceramics in 3D printing is, however, just at the beginning of a technical implementation in a continuously and fast rising field of research and development. The flexible fabrication of highly complex and precise 3D structures by means of light-induced photopolymerization that are difficult to realize using traditional ceramic fabrication methods such as casting and machining is of high importance. Generally, slurry-based ceramic 3D printing technologies involve liquid or semi-liquid polymeric systems dispersed with ceramic particles as feedstock (inks or pastes), depending on the solid loading and viscosity of the system. This paper includes all types of photo-curable polymer-ceramic-mixtures (feedstock), while demonstrating our own work on 3D printed alumina toughened zirconia based ceramic slurries with light induced polymerization on the basis of two-photon absorption (TPA) for the first time. As a proven exemplary on cuboids with varying edge length and double pyramids in the µm-range we state that real 3D micro-stereolithographic fabrication of ceramic products will be generally possible in the near future by means of TPA. This technology enables the fabrication of 3D structures with high accuracy in comparison to ceramic technologies that apply single-photon excitation. In sum, our work is intended to contribute to the fundamental development of this technology for the representation of oxide-ceramic components (proof-of-principle) and helps to exploit the high potential of additive processes in the field of bio-ceramics in the medium to long-term future. KW - Additive manufacturing KW - Ceramics 3D printing KW - Two-photon adsorption KW - Polymer-ceramic mixtures KW - Bio-ceramic engineering PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526672 DO - https://doi.org/10.3390/ceramics4020017 VL - 4 IS - 2 SP - 224 EP - 239 PB - MDPI CY - Basel AN - OPUS4-52667 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Strobl, Domninic T1 - PGD in thermal transient problems with a moving heat source – a sensitivity study on factors affecting accuracy and efficiency N2 - Thermal transient problems, essential in applications like welding and additive metal manufacturing, are characterized by a dynamic evolution of temperature. Accurately simulating these phenomena is often computationally expensive, thus limiting the application, e. g. for model parameter estimation or online process control. Model order reduction, a solution to preserve accuracy while reducing complexity, is explored. This paper addresses challenges in developing a reduced model using the Proper Generalized Decomposition (PGD) for transient thermal problems with a specific treatment of the moving heat source within the reduced model. Factors affecting accuracy, convergence, and computational cost, such as discretization methods (finite element and finite difference), a dimensionless formulation, the size of the heat source, and the inclusion of material parameters as additional PGD variables are examined across progressively complex examples. The results demonstrate the influence of these factors on the PGD model's performance and emphasize the importance of their consideration when implementing such models. For thermal examples it is demonstrated that a PGD model with a finite difference discretization in time, a dimensionless representation, a mapping for a moving heat source, and a spatial domain non-separation yields the best approximation to the full order model. KW - Additive manufacturing KW - Mapping for unseparable load KW - Model order reduction KW - Proper generalized decomposition KW - Sensitivity analysis KW - Thermal transient problem PY - 2024 DO - https://doi.org/10.5281/zenodo.10102489 PB - Zenodo CY - Geneva AN - OPUS4-62235 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hernández-Nava, E. A1 - Smith, C.J. A1 - Derguti, F. A1 - Tammas-Williams, S. A1 - Léonard, Fabien A1 - Withers, P. J. A1 - Todd, I. A1 - Goodall, R. T1 - The effect of defects on the mechanical response of Ti-6Al-4V cubic lattice structures fabricated by electron beam melting N2 - Electron Beam Melting (EBM) as a means of Additive Manufacturing (AM), is of interest for the fabrication of intricate geometries for cellular materials in areas where complex architectures are needed, e.g. biomedical implants. Most studies have focused on specific geometries and so the effect of the structure on mechanical performance is not well understood. Many kinds of micro- and macro-scale defects can arise in additively manufactured components, so assessment of their influence on properties is needed. In this work, lattices of Ti-6Al-4V having a cubic structure have been manufactured by EBM, and the effect of heat treatments above and below the β-transus temperature on microstructure and compression response have been investigated. The former modifies only slightly the α + β structure and mechanical performance whereas the latter leads to coarse alternating α and β lamellae packets and α at the prior grain boundaries with a 10% loss in yield strength. The variation in the compressive yield stress with strut diameter is in good accord with simple models based on compressive deformation rather than shearing or buckling. Internal pores for struts aligned with the build direction are found around the edges of the solid form, in regions which seem to be associated with the EB scan pattern. Struts normal to the build direction show more significant defects but their redundancy means that they do not compromise the compressive performance in the build direction. Using a particle size in the range 45–100 μm minimum weld-track sizes were experimentally and numerically identified to be 176 and 148 μm in depth respectively with a depth-to-width ratio of 0.55. This produced a beam pass of the order of 300 μm oversizing small features (struts of 0.4 and 0.6 mm nominal diameter) when a contour around the strut periphery was applied. KW - Cellular solids KW - Additive manufacturing KW - Titanium alloy KW - Mechanical properties KW - X-ray computed tomography PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-390686 DO - https://doi.org/10.1016/j.actamat.2016.02.029 SN - 1359-6454 VL - 108 SP - 279 EP - 292 PB - Elsevier Ltd. CY - Amsterdam [u.a.] AN - OPUS4-39068 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Graf, B. A1 - Gook, S. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Combined laser additive manufacturing for complex turbine blades N2 - Laser beam processes are increasingly used in the field of additive manufacturing. Prominent methods are either powderbed-based like Laser Metal Fusion (LMF), or utilizing a powder nozzle like Laser Metal Deposition (LMD). While LMF allows the manufacturing of complex structures, build rate, part volumes and material flexibility are limited. In contrast, LMD is able to operate with high deposition rates on existing parts, and materials can be changed easily during the process. However LMD shape complexity is limited. Utilizing their respective strengths, a combination of these two additive technologies has the potential to produce complex parts with high deposition rates and increased material flexibility. In this paper, combined manufacturing with additive technologies LMF and LMD is described. Its benefit for industry with emphasis on turbomachinery is shown. As reality test for the innovation, an industrial turbine blade is manufactured. KW - Turbine blade KW - Additive manufacturing KW - Laser metal fusion KW - Laser metal deposition PY - 2016 SN - 2499-9733 VL - 3 IS - 20 SP - 34 EP - 42 AN - OPUS4-38709 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Quosdorf, Heike T1 - A Digital Object Identifier for Additively Manufactured Parts as Open Source Software Package N2 - A method to uniquely identify samples without printed or handwritten labels is an advantage not just for additively manufactured parts. To kickstart industry use cases it is important to provide a ready made implementation kit. Following an open science and open source software approach Germanys Federal Institute for Materials Research and Testing BAM seeks to promote digital solutions of ongoing Research projects. With this software package a novel method based on microstructural features as identifiers DOI4AM (digital object identifier for additively manufactured parts will be explained alongside its implementation as open source Python software package. The digital object identifier (DOI) links product data clearly and forgery proof with real components. Its implementation helps to identify and securely authenticate additively manufactured components during its product life cycle by using characteristic microstructure features just like a fingerprint. To calculate the DOI fingerprint, a few preprocessing steps need to be performed to detect the uniquely distributed microstructure features that occur during the 3D printing process. A go through guide show s the preprocessing steps that include computer tomography (CT) image capturing, feature segmentation and data distribution via CSV files. While all steps can be followed along in a Jupyter notebook with sample data, the software package includes functions to create and compare fingerprints, as well, as an application programming interface (API) for integration in existing software platforms. A quick showcase of our industry partners implementation of the algorithm as containerized micro service in their digital product passport (DPP) web solution PASS X proves the first successful technology transfer of this project. T2 - MSE Research Data Forum 2025 CY - Siegburg, Germany DA - 08.07.2025 KW - Open Science KW - Authentication KW - Unique identification KW - Digital fingerprint KW - X-ray Computed Tomography KW - Additive manufacturing KW - Open Source Software PY - 2025 AN - OPUS4-63904 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geranmayeh, Ali T1 - Laser Metal Deposition of NiTi Shape Memory Alloys: Influence of Process Parameters on Thermal Profiles and Part Properties N2 - Laser Metal Deposition (LMD), a laser powder–directed energy deposition technology (LP-DED), offers unique flexibility for fabricating complex metallic components. Among candidate materials, Nitinol (NiTi) is particularly attractive due to its shape memory and superelastic properties, though its high sensitivity to processing conditions demands precise parameter control. In this work, prealloyed NiTi powder was deposited as single tracks, and process parameters were optimized using a Design of Experiments methodology. A Central Composite Design (CCD) was implemented with laser power, scan speed, and powder feed rate as inputs, while track’s height, width, aspect ratio, and dilution served as optimization responses. To address the strong susceptibility of NiTi to heat accumulation, hatch spacing was further optimized using a geometrically derived formula, enabling the use of maximum spacing while ensuring dense parts with smooth surfaces and minimal waviness. The presented framework establishes a systematic route for parameter optimization in NiTi LMD, offering practical guidelines for balancing densification and surface quality. T2 - WGF Assistant Seminar CY - Rechenberg-Bienenmühle, Germany DA - 10.09.2025 KW - Additive manufacturing KW - Shape memory alloys KW - Nitinol KW - Laser metal deposition KW - Design of experiments PY - 2025 AN - OPUS4-64164 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Linden, Anna T1 - AMVAD - Additive manufacturing for ventricular assist devices N2 - Some children are born with a univentricular heart, meaning their heart has only one pumping chamber instead of two. To improve circulation, patients often undergo the Fontan procedure, which reroutes blood flow — but this can put stress on other organs. In some cases, ventricular assist devices, or VADs, are used to support the heart’s pumping function. This involves an artificial pump connected directly to the patient's heart via silicone-based cannulas. Unique anatomical conditions introduce special challenges for cannula geometry. Additive manufacturing offers innovative solutions by enabling the production of personalized medical devices. The aim of the project is to develop the manufacturing workflow for the individualized cannula from digital imaging of the patient and customized design to additive manufacturing. Besides technical feasibility, validating the entire process is crucial for regulatory approval. The selection and testing of suitable additive manufacturing processes and biocompatible materials for individualized silicone cannulas, ensuring compliance with quality standards for high-risk medical products, will be presented. T2 - AMBER Spotlight On: 3D Printing meets Health & Biotech CY - Berlin, Germany DA - 16.09.2025 KW - Additive manufacturing KW - Medical device KW - Liquid silicone rubber PY - 2025 AN - OPUS4-64101 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -