TY - CHAP A1 - Schmidt, Jochen A1 - Fanselow, Stephanie A1 - Wirth, Karl-Ernst A1 - Peukert, Wolfgang A1 - Hiller, Saskia A1 - Laumer, Tobias A1 - Schmidt, Michael ED - Witt, Gerd ED - Wegner, Andreas ED - Sehrt, Jan T1 - Herstellung von Polyolefinstrahlschmelzmaterialien mittels Schmelzeemulgieren zum Einsatz in der additiven Fertigung T2 - Neue Entwicklungen in der Additiven Fertigung N2 - Im Rahmen dieses Beitrags wird das Schmelzeemulgieren als Verfahren zur Herstel-lung von Polymermikropartikeln vorgestellt. In diesem Prozess wird zunächst ein Polymergranulat in einer kontinuierlichen Phase in Gegenwart geeigneter Additive in einem Rührbehälter aufgeschmolzen, die Rohemulsion in einer Rotor-Stator-Einheit feinemulgiert und anschließend zu einer Suspension abgekühlt. Der Einfluss von Prozessparametern und Systemzusam-mensetzung auf das Emulgierergebnis wird diskutiert und die Anwendbarkeit des Verfahrens für polymere Mikropartikeln anhand von Polypropylen (PP) und Polyethylen (PE-HD) dargestellt. Die erhaltenen Suspensionen werden zur Überführung in Pulverform sprühgetrocknet und die Fließeigenschaften des Pulvers analysiert. Durch trockenes Beschichten mit pyrogener Kieselsäure kann die Fließfähigkeit der erhaltenen Partikeln weiter verbessert werden. Das Verfahren bietet somit einen neuen Zugang zur Herstellung neuer Ausgangsmaterialien für die Additive Fertigung. Y1 - 2015 SN - 978-3-662-48472-2 U6 - https://doi.org/10.1007/978-3-662-48473-9_2 SP - 13 EP - 23 PB - Springer CY - Berlin, Heidelberg ER - TY - JOUR A1 - Blümel, Christina A1 - Sachs, Marius A1 - Laumer, Tobias A1 - Winzer, Bettina A1 - Schmidt, Jochen A1 - Schmidt, Michael A1 - Peukert, Wolfgang A1 - Wirth, Karl-Ernst T1 - Increasing flowability and bulk density of PE-HD powders by a dry particle coating process and impact on LBM processes JF - Rapid Prototyping Journal N2 - Purpose – The purpose of this paper is to demonstrate the processability of cohesive PE-HD particles in laser beam melting processes (LBM) of polymers. Furthermore, we present a characterization method for polymer particles, which can predict the quality of the powder deposition via LBM processes. Design/methodology/approach – This study focuses on the application of dry particle coating processes to increase flowability and bulk density of PE-HD particles. Both has been measured and afterwards validated via powder deposition of PE-HD particles in a LBM machine. Findings – For efficient coating in a dry particle coating process, the PE-HD particles and the attached nanoparticles need to show similar surface chemistry, i.e. both need to behave either hydrophobic or hydrophilic. It is demonstrated that dry particle coating is appropriate to enhance flowability and bulk density of PE-HD particles and hence considerably improves LBM processes and the resulting product quality. Originality/value – At present, in LBM processes mainly polyamide (PA), 12 particles are used, which are so far quite expensive in comparison to, for example, PE-HD particles. This work provides a unique and versatile method for nanoparticulate surface modification which may be applied to a wide variety of materials. After the coating, the particles are applicable for the LBM process. Our results provide a correlation between flowability and bulk density and the resulting product quality. KW - Polymers KW - Bulk density KW - Dry particle coating KW - Flowability KW - Hydrophilic KW - Hydrophobic Y1 - 2015 U6 - https://doi.org/10.1108/RPJ-07-2013-0074 SN - 1758-7670 SN - 1355-2546 VL - 21 IS - 6 SP - 697 EP - 704 PB - Emerald ER - TY - JOUR A1 - Laumer, Tobias A1 - Karg, Michael Cornelius Hermann A1 - Schmidt, Michael T1 - Laser Beam Melting of Multi-Material Components JF - Physics Procedia N2 - First results regarding the realisation of multi-material components manufactured by Laser Beam Melting of polymers and metals are published. For realising composite structures from polymer powders by additive manufacturing, at first relevant material properties regarding compatibility have to be analysed. The paper shows the main requirements for compatibility between different materials and offers first results in form of a compatibility matrix of possible combinations for composite structures.For achieving gradient properties of additively manufactured metal parts by using composite materials the composition of alloying components in the powder and adapted process strategies are varied. As an alternative to atomizing pre-alloyed materials, mixtures of different powders are investigated. KW - additive manufacturing KW - laser beam melting Y1 - 2012 U6 - https://doi.org/10.1016/j.phpro.2012.10.068 SN - 1875-3892 SN - 1875-3884 VL - 39 SP - 518 EP - 525 PB - Elsevier ER - TY - CHAP A1 - Laumer, Tobias A1 - Karg, Michael Cornelius Hermann A1 - Schmidt, Michael T1 - Neue Prozessstrategien zur Herstellung von Multi- Material-Bauteilen und Gradientenwerkstoffen T2 - Zukunft individuell gestalten : Industriekolloquium des Sonderforschungsbereichs 814 - Additive Fertigung ; [Dezember 2012 ; Nürnberg] N2 - Das additive Fertigungsverfahren, dem gemeinhin die größten Potentiale zugesprochen werden, ist das Laserstrahlschmelzen im Pulverbett von Kunststoffen (LSS-K) und von Metallen (LSS-M). Wie bei anderen Techniken der additiven Fertigung werden Bauteile direkt aus CAD-Dateien ohne zusätzliche Werkzeuge bei enormer konstruktiver Freiheit gefertigt. Die resultierenden Werkstoffeigenschaften sind vergleichbar mit konventionelleren Prozessrouten wie etwa dem Spritzgießen thermoplastischer Polymere beziehungsweise auf der Seite der Metalle dem Schmieden oder Gießen. Derzeit wird der Einsatz des LSS zur Fertigung von Endprodukten in kleinen Stückzahlen erschwert von nicht ausreichender Prozessstabilität und, insbesondere bei Kunststoffen, von der eingeschränkten Werkstoffauswahl. Bisher werden für beide Werkstoffklassen Bauteile aus jeweils einem einzigen Ausgangsmaterial hergestellt. Näherungsweise erzeugt LSS also einheitliche Materialeigenschaften über das gesamte Bauteil hinweg. Ein Ansatz, der in den Teilprojekten A5 und B6 des Sonderforschungsbereichs 814 verfolgt wird, ist die Realisierung von Multi-Material-Bauteilen mittels LSS-K beziehungsweise LSS-M. Y1 - 2012 UR - https://www.researchgate.net/publication/338986395_Neue_Prozessstrategien_zur_Herstellung_von_Multi-_Material-Bauteilen_und_Gradientenwerkstoffen SP - 101 EP - 116 CY - Erlangen ER - TY - CHAP A1 - Laumer, Tobias A1 - Karg, Michael Cornelius Hermann A1 - Schmidt, Michael T1 - Additive Manufacturing of Gradient and Multimaterial Components T2 - International Conference on Competitive Manufacturing COMA, 2013, Stellenbosch N2 - In the paper first results regarding the realisation of gradient and multi-material parts manufactured by Laser Beam Melting in powder bed of metals and polymers are published. Gradient properties of additively manufactured metal parts can be achieved by varying the composition of alloying components in the powder and adapting process strategies. As an alternative to atomizing pre-alloyed materials, mixtures of different powders are investigated. For realizing multi-material-parts from polymers, at first relevant material properties concerning compatibility have to be analysed. Therefore the paper shows the main requirements for compatibility between different materials and also first results regarding the compatibility of polymer powders and possible combinations for the manufacturing of multi-material components by laser beam melting of polymers. KW - additive manufacturing KW - Laser Beam Melting in Powder Bed KW - New Materials Y1 - 2013 UR - https://www.researchgate.net/publication/318723870_Additive_Manufacturing_of_Gradient_and_Multimaterial_Components ER - TY - CHAP A1 - Laumer, Tobias A1 - Karg, Michael Cornelius Hermann A1 - Schmidt, Michael T1 - Neue Prozessstrategien zur Herstellung von Multi-Material-Bauteilen mit Hilfe des Laserstrahlschmelzens T2 - Industriekolloquium des SFB 814, 2, 2013, Nürnberg Y1 - 2013 UR - https://www.researchgate.net/publication/295861222_Neue_Prozessstrategien_zur_Herstellung_von_Multi-Material-Bauteilen_mit_Hilfe_des_Laserstrahlschmelzens SN - 978-3-931864-59-0 PB - Universität Erlangen-Nürnberg, Lehrstuhl für Kunststofftechnik ER - TY - CHAP A1 - Laumer, Tobias A1 - Schmidt, Michael A1 - Stichel, Thomas T1 - Influence of temperature gradients on the part properties for the simultaneous laser beam melting of polymers T2 - Proceedings of Laser in Manfacturing Conference 2015, June 22 - June 25, 2015 Munich, Germany N2 - By Laser Beam Melting of polymers (LBM), parts with almost any geometry can be built directly out of CAD files without the need for additional tools. Thus, prototypes or parts in small series production can be generated within short times. Up to now, no multi-material parts have been built by LBM, which is a major limitation of the technology. To realize multi-material parts, new mechanisms for depositing different polymer powders as well as a new irradiation strategy are needed, by which polymers with different melting temperatures can be warmed to their specific preheating temperatures and be molten simultaneously. This is achieved by simultaneous laser beam melting (SLBM). In the process, two different materials are deposited next to each other and preheated a few degrees below their melting temperatures by infrared emitters and laser radiation (λ = 10.60 µm), before in the last step the two preheated powders are molten simultaneously by an additional laser (λ = 1.94 µm). So far, multi-material tensile bars have been realized and analyzed regarding their boundary zone between both materials. The experiments showed that the temperature gradients in the boundary zone and along the building direction seem to be of great importance for the process stability and the resulting part properties. Therefore, a detailed analysis of the occurring temperature gradients during the process is needed to identify adequate process adjustments regarding the temperature controlling. To analyze the temperature gradients, thermocouples positioned inside the powder bed are used. By varying the temperature of the building platform, the influence of different temperature gradients on the resulting part properties is shown. KW - additive manufacturing KW - laser beam melting of polymers KW - multi-material parts Y1 - 2015 UR - https://www.wlt.de/lim/Proceedings/Stick/PDF/Contribution241_final.pdf ER - TY - JOUR A1 - Laumer, Tobias A1 - Stichel, Thomas A1 - Riedlbauer, Daniel A1 - Amend, Philipp A1 - Mergheim, Julia A1 - Schmidt, Michael T1 - Realization of multi-material polymer parts by simultaneous laser beam melting JF - Journal of Laser Micro / Nanoengineering N2 - In this paper, first results regarding the realization of multi-material parts by Simultaneous Laser Beam Melting (SLBM) of polymers are presented. This new approach allows the layerwise generation of parts consisting of different polymer materials within one building process. Besides the typical advantages of additive manufacturing technologies, such parts can fulfill different product requirements concomitant and therefore could enlarge the overall field of application. The powder materials used for this paper are polyethylene (PE) and a polyamide based thermoplastic elastomer (TPE). After depositing the powder materials next to each other, infrared-emitters heat the lower melting polymer and a CO2 laser provides the preheating temperature of the higher melting polymer. In the last step, a thulium fibre laser melts the two preheated powders simultaneously. The realized specimens are characterized by cross sections and their tensile strengths are determined. Additionally, the new approach of the simultaneous energy irradiation is investigated using a Finite Element Analysis in order to gain a more profound process understanding. In that sense, the influence of the size of the exposure area on the reachable maximum temperatures inside that area was analyzed by the simulation and compared to experimental studies. KW - additive manufacturing KW - Multi-Material Parts KW - NewMaterials KW - Simultaneous Laser Beam Melting of Polymers Y1 - 2015 UR - https://www.researchgate.net/publication/274250254_Realization_of_multi-material_polymer_parts_by_simultaneous_laser_beam_melting VL - 10 IS - 2 PB - Japan Laser Processing Society ER - TY - JOUR A1 - Laumer, Tobias A1 - Stichel, Thomas A1 - Amend, Philipp A1 - Schmidt, Michael T1 - Simultaneous laser beam melting of multimaterial polymer parts JF - Journal of Laser Applications N2 - By simultaneous laser beam melting (SLBM), parts consisting of different polymer powders can be additively manufactured within one building process. Besides the advantages of conventional LBM, e.g., not needing additional tools and being able to realize parts with almost any geometry, different product requirements can be achieved within a single part. Product requirements may be different chemical resistances or haptic material properties. Therefore, SLBM enlarges the application field for additive manufacturing in general. In the process, two different materials are deposited on the building platform and preheated a few degrees below the melting temperature of the lower melting polymer by infrared emitters. Afterward, a CO2 laser (λ = 10.6 μm) provides the energy for the temperature difference between the preheating temperatures of both materials. Finally, a digital light processing chip is used to achieve simultaneous and flexible energy deposition for melting both preheated polymers. By illuminating the chip with a laser, parts of the beam can be flexibly guided onto the powder bed or into a beam trap. As laser, a single mode thulium laser (λ = 1.94 μm) is used. After melting the layer, a new layer is deposited and the process starts anew. In this paper, polypropylene and polyamide 12 are used as materials. After analyzing the material and melting behavior during the process by a high-resolution thermal imaging system, the parts are qualified regarding their material compatibility at the boundary zone and porosity by cross sections. KW - additive manufacturing KW - material qualification KW - Multi-Material Parts KW - new processes Y1 - 2015 U6 - https://doi.org/10.2351/1.4906303 SN - 1938-1387 SN - 1042-346X VL - 27 IS - S2 PB - Laser Institute of America ER - TY - CHAP A1 - Laumer, Tobias A1 - Stichel, Thomas A1 - Amend, Philipp A1 - Roth, Stephan A1 - Schmidt, Michael T1 - Analysis of Temperature Gradients during Simultaneous Laser Beam Melting of Polymers T2 - Physics Procedia N2 - By simultaneous laser beam melting (SLBM), different polymer powders can be processed to multi-material parts, which offers the potential to enlarge the field of application for conventional LBM. In a SLBM process, a powder bed consisting of different polymers and therefore with different melting and crystallization temperatures is deposited. Besides the use of infrared emitters for preheating the lower melting polymer, a CO2 laser distributes the necessary preheating temperature of the higher melting polymer. In the last step, a thulium fibre laser distributes the energy necessary for melting the two preheated powders simultaneously. In order to analyze the temperature gradients of the process on the powder surface and in deeper layers, a high-resolution thermal imaging system and thermocouples are used. KW - Additive manufacturing KW - Multi-Material Parts KW - Process Qualification KW - Simultaneous Laser Beam Melting Y1 - 2014 U6 - https://doi.org/10.1016/j.phpro.2014.08.159 VL - 56 SP - 167 EP - 175 PB - Elsevier ER - TY - CHAP A1 - Laumer, Tobias A1 - Roth, Stephan A1 - Stichel, Thomas A1 - Schmidt, Michael T1 - Strategien zur Erzeugung von dreidimensionalen Multi-Material-Bauteilen T2 - 4. Industriekolloquium des Sonderforschungsbereichs 814 - Additive Fertigung 814, 2015, Nürnberg Y1 - 2015 UR - https://www.researchgate.net/publication/295860904_Strategien_zur_Erzeugung_von_dreidimensionalen_Multi-Material-Bauteilen SN - 978-3931864651 SN - 3931864650 ER - TY - JOUR A1 - Stichel, Thomas A1 - Laumer, Tobias A1 - Schmidt, Michael T1 - Simulation des (quasi-)simultanen Laserstrahlschmelzens zur Herstellung von Multi-Material-Bauteilen aus Polymeren JF - Rapid.Tech + FabCon 3.D - International Trade Show + Conference for Additive Manufacturing Y1 - 2018 U6 - https://doi.org/10.3139/9783446458123.020 SP - 312 EP - 329 PB - Hanser ER -