@inproceedings{RieserZimmermann2023, author = {Rieser, Jasper and Zimmermann, Markus}, title = {On the design of internal features for additive manufacturing}, series = {Tagungsband 11. Landshuter Leichtbau-Colloquium: Leichtbau - Werkstoffe, Konstruktionen, Fertigungstechnologien}, booktitle = {Tagungsband 11. Landshuter Leichtbau-Colloquium: Leichtbau - Werkstoffe, Konstruktionen, Fertigungstechnologien}, editor = {Huber, Otto and Bicker, Marc and Patzelt, Peter}, publisher = {LC-Verlag, Hochschule Landshut}, address = {Landshut}, isbn = {978-3-9812696-7-2}, doi = {10.57688/445}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:860-opus4-4452}, pages = {76 -- 85}, year = {2023}, abstract = {Internal features are one of the biggest drivers for geometrical part complexity and pose a major challenge for manufacturing. A prominent example is the removal of material from a part interior as a simple though effective way to realize hollow sections, cavities or internal passages. While machining will most often be inapplicable, these features are in principle well within the feasible range of additive manufacturing (AM). However, careful design is essential to ensure a reasonable manufacturability since post-processing of internal features is possible only to a very limited extend. This paper reviews common applications of internal features and proposes a size-dependent classification helping to select appropriate design recommendations. The concept was applied to the design problem of a probe rake used for flow measurement where achieving a sufficiently large first natural frequency, integration of internal pressure channels and ensuring a good manufacturability were the main challenges. Starting from a solid conventional design, several new design variants were developed by introducing internal features of different size. The final design exhibits a large first natural frequency that was almost two times higher compared to a conventional rake design while the mass could be reduced by 30 \%. A prototype was printed successfully from nickel-based super alloy on a selective laser melting system.}, language = {en} } @inproceedings{WhitmoreNischlerHuber2023, author = {Whitmore, Lawrence and Nischler, Anton and Huber, Otto}, title = {Preparation of magnesium AZ31B for electron backscatter diffraction (EBSD) analysis}, series = {Tagungsband 11. Landshuter Leichtbau-Colloquium: Leichtbau - Werkstoffe, Konstruktionen, Fertigungstechnologien}, booktitle = {Tagungsband 11. Landshuter Leichtbau-Colloquium: Leichtbau - Werkstoffe, Konstruktionen, Fertigungstechnologien}, editor = {Huber, Otto and Bicker, Marc and Patzelt, Peter}, publisher = {LC-Verlag, Hochschule Landshut}, address = {Landshut}, isbn = {978-3-9812696-7-2}, doi = {10.57688/446}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:860-opus4-4469}, pages = {86 -- 105}, year = {2023}, abstract = {A method for preparing magnesium alloy surfaces for metallographic study and electron backscatter diffraction (EBSD) analysis is presented. An alkaline polishing paste with a dispersion of alumina particles is used for more rapid preparation and a self-made low-power 3D printed vibratory polishing machine is used for final polishing. A final cleaning stage is developed to optimize surface quality after polishing, and an analysis is made on the effects of different solutions on surface corrosion. The method facilitates smaller groups and experimental projects on a small budget and, when combined with biodegradable filaments, can help labs meet sustainable development goals. The method and process for preparing samples are evaluated by examining the quality of magnesium AZ31B surfaces using optical and electron microscopy and EBSD orientation mapping.}, language = {en} } @inproceedings{LeubecherVitaleMusiletal.2023, author = {Leubecher, Dominik and Vitale, Pablo and Musil, Bruno and Brier, Steffen and H{\"o}fer, Philipp}, title = {Analysis and interpretation of the temperature field in additive material extrusion process for small and large scale components: A numerical study}, series = {Tagungsband 11. Landshuter Leichtbau-Colloquium: Leichtbau - Werkstoffe, Konstruktionen, Fertigungstechnologien}, booktitle = {Tagungsband 11. Landshuter Leichtbau-Colloquium: Leichtbau - Werkstoffe, Konstruktionen, Fertigungstechnologien}, editor = {Huber, Otto and Bicker, Marc and Patzelt, Peter}, publisher = {LC-Verlag, Hochschule Landshut}, address = {Landshut}, isbn = {978-3-9812696-7-2}, doi = {10.57688/447}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:860-opus4-4474}, pages = {106 -- 123}, year = {2023}, abstract = {Large-scale material extrusion processes, especially for thermoplastic polymers, have become increasingly common in research and industry in recent years. Due to the new time and size dimensions of the extrudate strands to be deposited, compared to small-scale manufacturing processes, challenges are revealed that have not yet been sufficiently researched to this extent. The present work is intended to make a numerical contribution to this in order to obtain a better understanding of the manufacturing processes and to investigate the influences on the temperature field as a result of different printing parameters and the selected deposition path. Further a workflow is presented on how the source code generated by the slicer can be incorporated into the thermal model. As a conclusion of the numerical results obtained, it can already be stated that the selected process parameters have a considerable influence on the temperature field, especially through the nozzle variation.}, language = {en} } @inproceedings{NeumeyerKropkaJonecketal.2021, author = {Neumeyer, Thomas and Kropka, Michael and Joneck, Julian and Loegel, Marc and Kirchmeier, Kathrin and M{\"u}hlbacher, Mathias and Altst{\"a}dt, Volker}, title = {Functionalized Oriented Composites - FORCE: A holistic approach from UD-tape to final part}, series = {Tagungsband 10. Landshuter Leichtbau-Colloquium: Leichtbau - von der Wissenschaft bis zur Schl{\"u}sseltechnologie f{\"u}r Ressourceneffizienz}, booktitle = {Tagungsband 10. Landshuter Leichtbau-Colloquium: Leichtbau - von der Wissenschaft bis zur Schl{\"u}sseltechnologie f{\"u}r Ressourceneffizienz}, editor = {Huber, Otto and Bicker, Marc and Patzelt, Peter}, publisher = {LC-Verlag / Hochschule Landshut}, address = {Landshut}, isbn = {978-3-9818439-5-8}, doi = {10.57688/455}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:860-opus4-4550}, pages = {10 -- 20}, year = {2021}, abstract = {Continuous fiber reinforced polymers based on thermoplastic matrices permit short cycle times as no curing step is needed and ancillary times can be reduced. Thus, they are promising candidates for high volume production of lightweight structures. In this paper a processing chain developed by Neue Materialien Bayreuth GmbH (NMB), named FORCE - Functionalized Oriented Composites is discussed: It enables cost efficient production of parts with tailored reinforcements employing unidirectionally fiber reinforced tapes (UD-tapes). State of the art preforming concepts result in high material scrap (often above 25 \%), which consequently leads to elevated material costs. Furthermore, machine technologies known from thermoset based aerospace processes are too slow to serve in line with the cycle time of an injection molding press. In this work, a concept for a high-speed tape laying machine, based on two tables, first one for lay-up, the second one - which is turnable - for orientation and stacking, is presented. The equipment called FORCE Placement uses up to four different UD-tapes with different width in order to compromise between minimum laying time and reduced scrap. Besides the machine concept, a digital twin of the equipment which allows a virtual planning of the lay-up strategy and provides an estimation on costs and CO2 footprint of the intended preform is established. Furthermore, a cradle to gate life cycle assessment for an exemplary demonstrator part has been performed considering two different preform lay-ups. It is shown that in order to achieve the minimum CO2 footprint, saving potentials on the side of materials and process technologies must be used equally. Loadoptimized hybrid structures consisting of glass and carbon fiber reinforcement are shown to be an appropriate concept.}, language = {en} } @inproceedings{BrandmayrRappLeubecheretal.2023, author = {Brandmayr, Felix and Rapp, Helmut and Leubecher, Dominik and H{\"o}fer, Philipp}, title = {Contribution to the determination of the stiffness of ±45° FRP laminates}, series = {Tagungsband 11. Landshuter Leichtbau-Colloquium: Leichtbau - Werkstoffe, Konstruktionen, Fertigungstechnologien}, booktitle = {Tagungsband 11. Landshuter Leichtbau-Colloquium: Leichtbau - Werkstoffe, Konstruktionen, Fertigungstechnologien}, editor = {Huber, Otto and Bicker, Marc and Patzelt, Peter}, publisher = {LC-Verlag, Hochschule Landshut}, address = {Landshut}, isbn = {978-3-9812696-7-2}, doi = {10.57688/441}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:860-opus4-4410}, pages = {20 -- 33}, year = {2023}, abstract = {Great discrepancies prevail between experimental investigations and conventional theoretical considerations of ±45° fibre reinforced plastics' Young's modulus. The examined multi-layer composites possess inhomogeneities on microscopic scale, most notably layers or bundles with locally increased fibre volume fraction. Therefore, an analytical approach is derived to characterise the composite's stiffness on macroscopic scale correctly. Application to experimental data confirms the approach which is also of interest for additive manufacturing of long fibre reinforced composites.}, language = {en} }