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 - Amend, Philipp A1 - Laumer, Tobias A1 - Roth, Stephan A1 - Baat, Florian A1 - Schmidt, Michael T1 - Investigations on Laser-based Hot-melt Bonding of Additive Manufactured Plastic Parts to Metal Sheets for Strong and Tight Multi-material Joints T2 - Laser in Manufacturing (LIM 2017), Munich, Germany N2 - In this paper, first results regarding the realization of laser-based hot-melt bonding of additive manufactured plastics parts to metal sheets for strong and tight multi-material joints are presented. Compared to earlier investigations, in which nearly solely extruded plastic materials were applied, the use of additive manufactured plastics complements the research field with a promising approach. Besides the typical advantages of multi-material joints regarding weight reduction and high strengths, such parts can meet the needs of constructional freedom and the avoiding of tool costs. Materials used for this paper are aluminum (AlMg3), stainless steel (1.4301) and polyamide 12 (PA12). The performed experiments resulting in multi-material joints between metal and polyamide. The realized specimens undergo a tensile shear test and a tightness test, in which the characteristics of the joints are determined. KW - additive manufacturing KW - Laser-based hot-melt bonding KW - multi-material joint Y1 - 2017 UR - https://www.researchgate.net/publication/318110485_Investigations_on_Laser-based_Hot-melt_Bonding_of_Additive_Manufactured_Plastic_Parts_to_Metal_Sheets_for_Strong_and_Tight_Multi-material_Joint ER - TY - JOUR A1 - Laumer, Tobias T1 - Realization of Multi-material Polymer Parts by Simultaneous Laser Beam Melting JF - Journal of Laser Micro/Nanoengineering (JLMN) 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 U6 - https://doi.org/10.2961/jlmn.2015.02.0006 VL - 10 IS - 2 SP - 140 EP - 147 PB - Japan Laser Processing Society 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 - JOUR A1 - Laumer, Tobias A1 - Wudy, Katrin A1 - Drexler, Maximilian A1 - Amend, Philipp A1 - Roth, Stephan A1 - Drummer, Dietmar A1 - Schmidt, Michael T1 - Fundamental investigation of laser beam melting of polymers for additive manufacture JF - Journal of Laser Applications N2 - By selective laser sintering (SLS), polymer powders are molten layer by layer to build conventional prototypes or parts in small series with geometrical freedom that cannot be achieved by other manufacturing technologies. The SLS process is mainly defined by the beam–matter interaction between powder material, laser radiation and different material characteristics by itself. However the determination of these different material characteristics is problematic because powder material imposes certain requirements that cannot sufficiently be provided by conventional measurement methods. Hence new fundamental investigation methods to determine the optical and thermal material characteristics like the thermal diffusivity, thermal conductivity, or the influence of different heating rates on the melting behavior are presented in this paper. The different analysis methods altogether improve the process of understanding to allow recommendations for the future process controlling. Y1 - 2014 U6 - https://doi.org/10.2351/1.4892848 SN - 1938-1387 SN - 1042-346X VL - 26 IS - 4 PB - AIP Publishing ER - TY - JOUR A1 - Kuettner, Andreas A1 - Raths, Max A1 - Fischer, Samuel A1 - Laumer, Tobias T1 - Heat staking of polymer parts generated by fused layer modeling JF - The International Journal of Advanced Manufacturing Technology N2 - Heat staking is a joining technology by which thermoplastic pins are formed by force and temperature to create a form- and force-fitting connection between components. This paper examines the characteristics of 3D printed pins in comparison to conventionally turned pins for heat staking applications. The 3D printed pins are created using fused layer modeling, with variations in horizontal and vertical building directions, as well as different layer thicknesses. The study investigates the impact of significant factors on the heat staking process, including the forming force and temperature. Tensile tests, micrographs, and micro-CT measurements were conducted to determine the properties of the heat-staked joints. Additionally, a stage plan was developed to enhance the understanding of the forming process of both printed and conventionally turned materials. The findings suggest that, under specific process parameters, 3D printed pins exhibit comparable strength to conventionally manufactured pins. The research also demonstrates that the anisotropy resulting from the layer-by-layer construction of the pins significantly influences the strength of the connection. Furthermore, the study reveals that 3D printed pins exhibit good forming accuracy during the heat staking process, and the cavities formed during printing can be substantially reduced. KW - Heat staking KW - Additive manufacturing KW - 3D printing KW - Material qualification KW - Polycarbonate (PC) KW - Fused layer modeling (FLM) Y1 - 2023 U6 - https://doi.org/10.1007/s00170-023-11850-y VL - 128 SP - 547 EP - 562 PB - Springer Nature ER - TY - JOUR A1 - Raths, Max A1 - Bauer, Lukas A1 - Kuettner, Andreas A1 - Fischer, Samuel A1 - Laumer, Tobias T1 - Gradual error detection technique for non-destructive assessment of density and tensile strength in fused filament fabrication processes JF - The International Journal of Advanced Manufacturing Technology N2 - Fused filament fabrication (FFF) is a widely used additive manufacturing process for producing functional components and prototypes. The FFF process involves depositing melted material layer-by-layer to build up 3D physical parts. The quality of the final product depends on several factors, including the component density and tensile strength, which are typically determined through destructive testing methods. X-ray microtomography (XCT) can be used to investigate the pore sizes and distribution. These approaches are time-consuming, costly, and wasteful, making it unsuitable for high-volume manufacturing. In this paper, a new method for non-destructive determination of component density and estimation of the tensile strength in FFF processes is proposed. This method involves the use of gradual error detection by sensors and convolutional neural networks. To validate this approach, a series of experiments has been conducted. Component density and tensile strength of the printed specimens with varying extrusion factor were measured using traditional destructive testing methods and XCT. The cumulative error detection method was used to predict the same properties without destroying the specimens. The predicted values were then compared with the measured values, and it was observed that the method accurately predicted the component density and tensile strength of the tested parts. This approach has several advantages over traditional destructive testing methods. The method is faster, cheaper, and more environmentally friendly since it does not require the destruction of the product. Moreover, it facilitates the testing of each individual part instead of assuming the same properties for components from one series. Additionally, it can provide real-time feedback on the quality of the product during the manufacturing process, allowing for adjustments to be made as needed. The advancement of this approach points toward a future trend in non-destructive testing methodologies, potentially revolutionizing quality assurance processes not only for consumer goods but various industries such as electronics or automotive industry. Moreover, its broader applications extend beyond FFF to encompass other additive manufacturing techniques such as selective laser sintering (SLS), or electron beam melting (EBM). A comparison between the old destructive testing methods and this innovative non-destructive approach underscores the possible fundamental change toward more efficient and sustainable manufacturing practices. This approach has the potential to significantly reduce the time and cost associated with traditional destructive testing methods while ensuring the quality of FFF-manufactured products. KW - Error detection KW - Additive manufacturing KW - Fused filament fabrication KW - Artificial neural network KW - Image processing KW - Porosity Y1 - 2024 U6 - https://doi.org/10.1007/s00170-024-13280-w SN - 1433-3015 SN - 0268-3768 N1 - Open Access funding enabled and organized by Projekt DEAL. IS - 131 SP - 4149 EP - 4163 PB - Springer CY - London ER - TY - CHAP A1 - Laumer, Tobias A1 - Stichel, Thomas A1 - Amend, Philipp A1 - Schmidt, Michael A1 - Gachot, A. T1 - Simultaneous Energy Deposition for Laser Beam Melting of Polymers T2 - Proceedings of the Polymer Processing Society 29th Annual Meeting, Nürnberg, 2013 Y1 - 2013 PB - American Institute of Physics CY - New York ER - TY - JOUR A1 - Stichel, Thomas A1 - Frick, Thomas A1 - Laumer, Tobias A1 - Tenner, Felix A1 - Hausotte, Tino A1 - Merklein, Marion A1 - Schmidt, Michael T1 - A Round Robin study for Selective Laser Sintering of polyamide 12: Microstructural origin of the mechanical properties JF - Optics & Laser Technology N2 - The mechanical and microstructural investigation of polymer parts (polyamide 12) fabricated by Selective Laser Sintering as part of a Round Robin initiative is presented. The paper focuses on the microstructural analysis of the Round Robin samples and their evaluation regarding their effect on mechanical properties with respect to each other. Therefore optical microscopy on microtomed samples, X-ray computed tomography and Differential Scanning Calorimetry is used to determine the morphology of residual particle cores and of internal pores. Y1 - 2017 U6 - https://doi.org/10.1016/j.optlastec.2016.09.042 VL - 89 SP - 31 EP - 40 PB - Elsevier ER -