wbk Institute of Production Science

New Publications

[ 1 ] Moll, P.; Pirrung, F.; Baranowski, M.; Coutandin, S. & Fleischer, J. (2020), "Evaluation of Fiber Placement Strategies for the Implementation of Continuous". SAMPE 2020 Virtual Series |??Additive Manufacturing.
Abstract
Among engineering materials today continuous fiber reinforced polymers (FRP) show some of the highest stiffness and strength to weight ratios. To rival the traditional manufacturing methods of continuous FRP many investigations have sought to combine the outstanding mechanical performances of these materials with the freedom in design and the economic benefits of additive manufacturing (AM). This paper focuses on the fiber placement strategies and their interaction with Selective Laser Sintering (SLS) specific machine features. The goal is to develop and conduct test series to gain a deeper understanding of how the process, the polymer, and the reinforcement fibers interact. For this investigation different patterns of glass fiber rovings are embedded into specimens made from PA 12 on a Sintratec Kit printer. The rovings are put up onto a frame in varying patterns to be able to relate fiber tension and curvature as well as the stack height of intersecting rovings to the quality of embedding. Additionally the time of placement, the clamping and the interaction of the fibers with the recoater have been investigated. Based on these results an SLS printer with automated continuous fiber implementation will be developed in the future.

[ 2 ] Nieschlag, J.; Coutandin, S. & Fleischer, J. (2020), "Production and Tensile Testing of Rotationally Molded Hybrid Composite Tie Rods". SAMPE 2020 Virtual Series | Multifunctional Materials and Structures.
Abstract
An innovative production processes for manufacturing rotationally symmetric FRP-metal components, such as drive shafts or tie rods, is the rotational molding process. In the course of this process, a dry fiber preform and metallic load-introduction elements are inserted into a two-piece mold and subsequently clamped into a spindle. The matrix is injected directly into the rotating mold. Due to the arising centrifugal forces, the preform is impregnated and the component cures under rotation. In comparison to conventional joining processes, such as adhesive bonding or bolt connections, the metallic components as well as the FRP part are intrinsically joined during the forming process. A downstream joining process is not required. The joint is based either on the adhesive property of the matrix system or on a form-fit geometry with undercuts. The paper addresses the production and tensile testing of tie rods. Different rod geometries and different surface treatments, including sandblasting, knurling, and arc spraying, are compared and evaluated.

[ 3 ] Fleischer, J.; Schäfer, J.; Wößner, W. & Hofmann, J. (2020), "Leitfaden Fit4E".
Abstract
Die Elektrifizierung des Antriebsstranges wird von vielen Unternehmen als große Herausforderung gesehen: Für Bauteile oder Produktionsanlagen, die bisher fest im Produktportfolio des Unternehmens verankert waren, wird eine stark abnehmende Bedeutung erwartet. Gleichzeitig sind neue Produkte und Fertigungsanlagen gefragt – Der Transformationsprozess zur Elektromobilität kann somit auch als Chance verstanden werden, dort eigene fertigungstechnische Kompetenzen einzubringen und zusätzlich notwendige Kompetenzen aufzubauen. Zielsetzung des Leitfadens Fit4E ist es insbesondere, kleine und mittlere Unternehmen dabei methodisch zu unterstützen, diese Chance wahrzunehmen und somit am wachsenden Markt Elektromobilität zu partizipieren. Grundlage des Leitfadens ist ein Workshopkonzept, welches bei zwei Pilotunternehmen erprobt und weiterentwickelt wurde. Der Inhalt des Leitfadens orientiert sich dabei an den drei Phasen eines Workshops (Vorbereitung, Durchführung und Nachbereitung) und stellt darin die jeweils eingesetzten Methoden vor. Neben der vermittelten Wissensbasis können in den Workshops erste vielversprechende neue Anwendungsgebiete identi ziert werden. Dadurch kann der Workshop als Grundlage zur systematischen Entwicklung neuer Geschäftsfelder eingesetzt werden.

[ 4 ] Schäfer, J.; Weinmann, H. W.; Mayer, D.; Storz, T. & Hofmann, J. (2020), "Synergien zwischen Batterie- und Brennstoffzelle", pp. 735-741. [30.11.-1].
Abstract
Nach Ankündigung diverser batterieelektrischer Modelle wird auch die PEM (Proton Exchange Membrane)-Brennstoffzelle als mögliche Zukunftstechnologie im Last- und Linienverkehr diskutiert. Ob und wann sich eine Technologie durchsetzt, hängt von der verwendeten Produktionstechnik ab, denn diese bestimmt Stückzahlen und resultierende Kosten. Die Vergangenheit zeigt, dass sich produzierende Industrien oft entlang vorhandener Kompetenzen in etablierten Bereichen entwickelt haben. In diesem Beitrag sollen daher Synergiepotenziale zwischen der Batterie- und Brennstoffzellenfertigung diskutiert werden.

[ 5 ] Wurba, A.; Hofmann, J.; Fleischer, J.; Klemens, J.; Scharfer, P. & Schabel, W. (2020), "Identifying the influence of the particle size and morphology of electrode materials on the process of calendering". Conference Brochure, eds. Prof. Arno Kwade, S. D., pp. 22.
Abstract
Current developments in the electric mobility sector and the need for the storage of energy from renewable sources lead to a growing demand for lithium-ion batteries (LIB). Although they provide high energy densities, the increasing requirements push this technology to its performance limits. Furthermore some of the commonly used electrode raw materials face alarming political, ecological and economic risks. The DFG-funded project POLiS Cluster of Excellence therefore aims to develop sustainable battery materials to produce safer batteries with higher performance properties. In addition to the choice of the material each process step has an impact on future cell performance. High energy densities are obtained by a properly adjusted calendering process. The compression of the electrode material leads among other improvements to an increase of the volumetric energy density. Hence, it is of great importance to understand the process of calendering to achieve satisfying electrochemical cell properties. This work investigates the influence of material characteristics on the calendering process. One promising post-lithium candidate is sodium with its corresponding anode material hard carbon. This study focusses on analysing the correlation between the particle size and morphology of hard carbon and the generated anode properties after calendering. Furthermore the slurry composition and drying conditions are taken into account. Line load, web tension and temperature are varied calendering process parameters. Resulting compaction rates and adhesive forces are presented and scanning electron microscopy images complete the analysis of the material behavior. A stereo camera system quantifies the distortions caused by calendering. Finally conductivity measurements rate the quality of the calendered anode material. These results contribute to building a tool for the prediction of the processability of future battery materials.

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