TY - GEN A1 - Breuß, Michael A1 - Buhl, Johannes A1 - Mansouri Yarahmadi, Ashkan A1 - Bambach, Markus A1 - Peter, Pascal T1 - A Simple Approach to Stiffness Enhancement of a Printable Shape by Hamilton-Jacobi Skeletonization T2 - Procedia Manufacturing N2 - The 3D-Printing technology is ready to produce parts with specific properties like individual stiffness. Based on a predefined outer shape, the inner structure of a printed part defines mainly the mechanical features. By Hamilton-Jacobi skeletonization, a stiffness enhancement of a printable shape can be achieved in a way, that a novel AM-corner includes linear axis function. Originating in the field of shape analysis in computer vision and graphics, the so-called medial axis transform (MAT) is designed for the computation of a structure that resembles the bone structure of biological shapes. The input for MAT computation is typically a shape’s boundary. The arising topological skeletons have proven to provide a useful concept for many applications; however, their computation is generally intricate and also known to rely on many parameters, diminishing the accessibility of skeletonization methods. In this work, the classical Hamilton-Jacobi skeletonization approach is adopted to compute a stability enhancing shape structure. As the basic method has not been designed for the context of additive manufacturing, a set of suitable modifications are introduced to design an algorithm that suits our intended purpose. Unlike the traditional skeletonization schemes, the resulting method appears to be robust and in practice almost completely automated as we can identify useful generic parameter settings. By a finite element method (FEM) study, the elastic stress properties of the AM-corner with linear axis function is validated and printed with in metal (1.4404) with the 3D Selected Laser Melting (SLM) system AconityMIDI. The AM-knot with skeletonization guides approximately 20 times better than a standard knot. While the first obtained results are shown as 2.5 dimensional shapes, it is emphasized that the proposed algorithm offers many possibilities for extensions to three dimensions and variations in context of additive manufacturing. KW - Skeletonization KW - Hamilton-Jacobi skeletonization KW - stiffness enhancement KW - 3D printing KW - additive manufacturing Y1 - 2020 U6 - https://doi.org/10.1016/j.promfg.2020.04.147 SN - 2351-9789 N1 - 23rd International Conference on Material Forming (ESAFORM 2020) VL - Vol. 47 SP - 1190 EP - 1196 ER - TY - GEN A1 - Buhl, Johannes A1 - Hart-Rawung, Thawin A1 - Bambach, Markus T1 - Nutzung von Neuralen Netzen zur effizienten Auslegung des Presshärtens von 22MnB5 T2 - Tagungsband zum 15. Erlanger Workshop Warmblechumformung, Erlangen, den 17. November 2020 Y1 - 2020 SN - 978-3-00-066911-8 SP - 99 EP - 112 PB - Lehrstuhl für Fertigungstechnologie, Friedrich-Alexander-Universität Erlangen-Nürnberg CY - Erlangen ER - TY - GEN A1 - Bähr, Martin A1 - Buhl, Johannes A1 - Radow, Georg A1 - Schmidt, Johannes A1 - Bambach, Markus A1 - Breuß, Michael A1 - Fügenschuh, Armin T1 - Stable honeycomb structures and temperature based trajectory optimization for wire-arc additive manufacturing T2 - Optimization and Engineering N2 - We consider two mathematical problems that are connected and occur in the layer-wise production process of a workpiece using wire-arc additive manufacturing. As the first task, we consider the automatic construction of a honeycomb structure, given the boundary of a shape of interest. In doing this, we employ Lloyd’s algorithm in two different realizations. For computing the incorporated Voronoi tesselation we consider the use of a Delaunay triangulation or alternatively, the eikonal equation. We compare and modify these approaches with the aim of combining their respective advantages. Then in the second task, to find an optimal tool path guaranteeing minimal production time and high quality of the workpiece, a mixed-integer linear programming problem is derived. The model takes thermal conduction and radiation during the process into account and aims to minimize temperature gradients inside the material. Its solvability for standard mixed-integer solvers is demonstrated on several test-instances. The results are compared with manufactured workpieces. KW - Mixed-integer linear programming KW - Geometric optimization KW - Eikonal equation KW - Heat transmission KW - Additive manufacturing KW - Centroidal Voronoi tesselation Y1 - 2021 U6 - https://doi.org/10.1007/s11081-020-09552-5 SN - 1573-2924 VL - 22 IS - 2 SP - 913 EP - 974 ER - TY - GEN A1 - Eisentraut, Mark A1 - Stendal, Johan Andreas A1 - Bolz, Sebastian A1 - Bambach, Markus A1 - Weiß, Sabine T1 - Applying a softening adapted acceleration to the hot deformation of TNM-B1 T2 - MRS Fall Meeting 2020 N2 - Hot isostatically forged TiAl turbine blades made of TNM-B1 are commercially used in aircraft engines, as they offer significantly lower weight than the traditional nickel-based blades while exhibiting similar strength. Like other TiAl alloys, TNM-B1 displays high peak stress followed by a strong softening behavior (i.e. stress reduction) during hot deformation. This softening can be used to accelerate the deformation process by reducing the processing time and in turn the costs for TNM-B1 parts. In order to avoid increased damage during the accelerated process, a pre-heat treatment (HT) for the hot isostatically pressed material (HIP) is required. To simulate the accelerated forming process, hot compression tests were performed with a DIL805A/D/T dilatometer from TA Instruments (New Castle, Delaware, USA) with different strain rates (0.0013, 0.005, 0.01 and 0.05) and temperatures (T=1150, 1175 and 1200°C). Deformation of the heat-treated state revealed lower flow stress (in both, peak stresses and steady state stresses) and fewer voids compared to the HIP state (Fig. 1.a). The compression test data were used to develop material and temperature specific strain rate profiles based on a material model. Subsequently, hot compression tests were performed with different strain rate profiles (starting strain rates 0.0013 and 0.0052) for the HIP and the HT state. The results were evaluated with regard to their microstructure, deformation, and damage behavior. A reduction of the processing time for all tested strain rates profiles by factors 2-3 could be achieved compared to constant strain rates. Furthermore, the results indicated that the deformation with strain rate profiles (compared to constant strain rates) did not significantly change the resulting microstructure or damage tolerance of the HT state. Y1 - 2020 UR - https://www.mrs.org/meetings-events/fall-meetings-exhibits/2020-mrs-spring-and-fall-meeting/call-for-papers/symposium-sessions-detail?code=F.SF07 ER - TY - GEN A1 - Brykarczyk, Daniel A1 - Lenz, Wolfgang A1 - Neumann, Andreas A1 - Bambach, Markus T1 - Erhöhung der Lebensdauer metallischer Strahlheizrohre durch den Einsatz strukturierter Bleche T2 - Prozesswärme Y1 - 2020 SN - 2567-3742 VL - 4 ER - TY - GEN A1 - Lenz, Wolfgang A1 - Brykarczyk, Daniel A1 - Pfeifer, Herbert A1 - Neumann, Andreas A1 - Bambach, Markus T1 - Theoretical limits of the increase of radiative heat transfer by increased surface areas of radiant tubes T2 - Applied Thermal Engineering Y1 - 2021 U6 - https://doi.org/10.1016/j.applthermaleng.2020.116246 SN - 1359-4311 VL - Vol. 184 ER - TY - GEN A1 - Stendal, Johan Andreas A1 - Eisentraut, Mark A1 - Sizova, Irina A1 - Bolz, Sebastian A1 - Weiß, Sabine A1 - Bambach, Markus T1 - Accelerated hot deformation and heat treatment of the TiAl alloy TNM-B1 for enhanced hot workability and controlled damage T2 - Journal of Materials Processing Technology Y1 - 2021 U6 - https://doi.org/10.1016/j.jmatprotec.2020.116999 SN - 0924-0136 VL - Vol. 291 ER - TY - GEN A1 - Hemes, Susanne A1 - Meiners, Frank A1 - Sizova, Irina A1 - Hama-Saleh, Rebar A1 - Röhrens, Daniel A1 - Weisheit, Andreas A1 - Häfner, Constantin Leon A1 - Bambach, Markus T1 - Microstructures and Mechanical Properties of Hybrid, Additively Manufactured Ti6Al4V after Thermomechanical Processing T2 - Materials Y1 - 2021 U6 - https://doi.org/10.3390/ma14041039 SN - 1996-1944 VL - 14 IS - 4 ER - TY - GEN A1 - Blumberg, Julian A1 - Li, Zhoulong A1 - Besong, Lemopi Isidore A1 - Polte, Mitchel A1 - Buhl, Johannes A1 - Uhlmann, Eckart A1 - Bambach, Markus T1 - Deformation error compensation of industrial robots in single point incremental forming by means of data-driven stiffness model T2 - 26th International Conference on Automation and Computing (ICAC), 2-4 Sept. 2021, Portsmouth, United Kingdom Y1 - 2021 SN - 978-1-86043-557-7 SN - 978-1-6654-4352-4 U6 - https://doi.org/10.23919/ICAC50006.2021.9594138 ER - TY - GEN A1 - Bambach, Markus A1 - Sizova, Irina A1 - Szyndler, Joanna A1 - Bennett, Jennifer A1 - Hyatt, Greg A1 - Cao, Jian A1 - Papke, Thomas A1 - Merklein, Marion T1 - On the hot deformation behavior of Ti-6Al-4V made by additive manufacturing T2 - Journal of Materials Processing Technology KW - Titanium KW - Additive manufacturing KW - Hot deformation Y1 - 2021 U6 - https://doi.org/10.1016/j.jmatprotec.2020.116840 SN - 0924-0136 SN - 1873-4774 VL - 288 ER - TY - GEN A1 - Sizova, Irina A1 - Sviridov, Alexander A1 - Bambach, Markus A1 - Eisentraut, Mark A1 - Hemes, Susanne A1 - Hecht, Ulrike A1 - Marquardt, Axel A1 - Leyens, Christoph T1 - A study on hot-working as alternative post-processing method for titanium aluminides built by laser powder bed fusion and electron beam melting T2 - Journal of Materials Processing Technology Y1 - 2021 U6 - https://doi.org/10.1016/j.jmatprotec.2020.117024 SN - 0924-0136 SN - 1873-4774 VL - 291 ER - TY - GEN A1 - Bambach, Markus A1 - Imran, Muhammad A1 - Sizova, Irina A1 - Buhl, Johannes A1 - Gerster, Stephan A1 - Herty, Michael T1 - A soft sensor for property control in multi-stage hot forming based on a level set formulation of grain size evolution and machine learning T2 - Advances in Industrial and Manufacturing Engineering Y1 - 2021 U6 - https://doi.org/10.1016/j.aime.2021.100041 SN - 2666-9129 IS - 2 ER -