@inproceedings{43240, author = {{Rüther, Torben and Jesinghausen, Steffen and Schmid, Hans-Joachim}}, title = {{{NEW CORRECTION APPROACHES FOR DETERMINING THE TRUE SHEAR RATE IN A COAXIAL-RHEOMETER (Vortrag)}}}, year = {{2022}}, } @article{30228, abstract = {{Confidence in additive manufacturing technologies is directly related to the predictability of part properties, which is influenced by several factors. To gain confidence, online process monitoring with dedicated and reliable feedback is desirable for every process. In this project, a powder bed monitoring system was developed as a retrofit solution for the EOS P3 laser sintering machines. A high-resolution camera records each layer, which is analyzed by a Region-Based Convolutional Neural Network (Mask R-CNN). Over 2500 images were annotated and classified to train the network in detecting defects in the powder bed at a very high level. Each defect is checked for intersection with exposure areas. To distinguish between acceptable imperfections and critical defects that lead to part rejection, the impact of these imperfections on part properties is investigated.}}, author = {{Klippstein, Sven Helge and Heiny, Florian and Pashikanti,, Nagaraju and Gessler, Monika and Schmid, Hans-Joachim}}, journal = {{JOM - The Journal of The Minerals, Metals & Materials Society (TMS)}}, location = {{Online}}, pages = {{1149–1157}}, publisher = {{Springer}}, title = {{{Powder Spread Process Monitoring in Polymer Laser Sintering and its Influences on Part Properties}}}, doi = {{https://doi.org/10.1007/s11837-021-05042-w }}, volume = {{74}}, year = {{2022}}, } @inproceedings{33356, abstract = {{By monitoring the recoating process within polymer laser sintering production, it was shown that multiple powder-spread-flaws can be detected. Those groove-like flaws are expected to be the result of agglomerates jamming between the recoater and the last powder layer. This work is analyzing the interaction between powder-spread-flaws and part properties, showing the influence of the recoating process on the performance of laser sintering parts. Therefore, artificial powder-spread-flaws are applied to the build jobs of tensile test specimens which are measured and analyzed regarding the elongation at break, strength and fracture position. For the characteristics of the flaws, the artificial grooves are varied in depth and width. Furthermore, the position of the flaw is changed form mid part to close to surface areas. It was shown, that several flaws are visible at the part surface, resulting in stress concentration and reduced performance. But there are as well parts with flaw-layers, which are not visible after the build process on the part. Those parts can have significantly reduced mechanical properties as well.}}, author = {{Klippstein, Sven Helge and Schmid, Hans-Joachim}}, booktitle = {{Proceedings of the 33nd Annual International Solid Freeform Fabrication Symposium}}, keywords = {{Selective Sasersintering, Process Monitoring, Powder Spread}}, title = {{{Powder Spread Flaws in Polymer Laser Sintering and its Influences on Mechanical Performance}}}, year = {{2022}}, } @article{44468, author = {{Schmidt, Stephan and Gräßer, Melanie and Schmid, Hans-Joachim}}, issn = {{1064-8275}}, journal = {{SIAM Journal on Scientific Computing}}, keywords = {{Applied Mathematics, Computational Mathematics}}, number = {{4}}, pages = {{B1175--B1194}}, publisher = {{Society for Industrial & Applied Mathematics (SIAM)}}, title = {{{A Shape Newton Scheme for Deforming Shells with Application to Capillary Bridges}}}, doi = {{10.1137/20m1389054}}, volume = {{44}}, year = {{2022}}, } @article{44469, author = {{Menge, Dennis and Schmid, Hans-Joachim}}, issn = {{1022-1360}}, journal = {{Macromolecular Symposia}}, keywords = {{Materials Chemistry, Polymers and Plastics, Organic Chemistry, Condensed Matter Physics}}, number = {{1}}, publisher = {{Wiley}}, title = {{{Low Temperature Laser Sintering with PA12 and PA6 on a Standard System}}}, doi = {{10.1002/masy.202100397}}, volume = {{404}}, year = {{2022}}, } @inproceedings{37436, author = {{Beimdiek, Janis and Prill, Friedrich and König, Mario and Müller, Mirjam and Hartmann, Ingo and Schmid, Hans-Joachim}}, booktitle = {{13th World Filtration Congress Proceedings}}, location = {{San Diego}}, title = {{{Combined filtration process for biomass combustion plants to comply with legal requirements (oral presentation)}}}, year = {{2022}}, } @inproceedings{37426, author = {{Beimdiek, Janis and Schmid, Hans-Joachim}}, booktitle = {{IAC 2022 Book of Abstracts}}, location = {{Athens}}, title = {{{A combined flue gas cleaning system with a novel entrained flow SCR using online synthesized catalyst particles (Poster)}}}, year = {{2022}}, } @inproceedings{37430, author = {{Beimdiek, Janis and Schmid, Hans-Joachim}}, location = {{Zürich}}, title = {{{Novel entrained flow SCR using online synthesized catalyst particles in flue gas cleaning systems (oral presentation)}}}, year = {{2022}}, } @article{25142, abstract = {{Additive Manufacturing provides the opportunity to produce tailored and complex structures economically. The use of lattice structures in combination with a thermoplastic elastomer enables the generation of structures with configurable properties by varying the cell parameters. Since there is only little knowledge about the producibility of lattice structures made of TPE in the laser sintering process and the resulting mechanical properties, different kinds of lattice structures are investigated within this work. The cell type, cell size and strut thickness of these structures are varied and analyzed. Within the experimental characterization of Dodecahedron-cell static and cyclic compression tests of sandwich structures are focused. The material exhibits hyperelastic and plastic properties and also the Mullins-Effect. For the later design of real TPE structures, the use of numerical methods helps to reduce time and costs. The preceding experimental investigations are used to develop a concept for the numerical modeling of TPE lattice structures.}}, author = {{Kummert, Christina and Schmid, Hans-Joachim and Risse, Lena and Kullmer, Gunter}}, issn = {{0884-2914}}, journal = {{Journal of Materials Research}}, title = {{{Mechanical characterization and numerical modeling of laser-sintered TPE lattice structures}}}, doi = {{10.1557/s43578-021-00321-3}}, year = {{2021}}, } @inproceedings{23760, abstract = {{The laser sintering process has been a well-established AM process for many years. Disadvantages of LS are the low material variety and the thermal damage of the unprocessed material. The low temperature laser sintering attacks at this point and processes powder material at a build chamber temperature lower than the recrystallization temperature. This drastic reduction in temperature results in significantly less thermal damage to the material. This work deals with the low temperature laser sintering of Polyamide 12 (PA12) on a commercial, unmodified laser sintering system to compare it to standard laser sintered PA12 and to create the basis for low temperature laser sintering of high temperature materials on such a system. First results by changing the exposure parameters and by fixing parts on a building platform show a processing of PA12 on an EOS P396 at a build chamber temperature less than 100 °C instead of standard approx. 175 °C.}}, author = {{Menge, Dennis and Schmid, Hans-Joachim}}, keywords = {{Low Temp LS, Low Temperature Laser Sintering, Polyamid 12}}, location = {{Austin, TX}}, title = {{{Low Temperature Laser Sintering on a Standard System: First Attempts and Results with PA12}}}, year = {{2021}}, } @inproceedings{30364, author = {{Tischendorf, Ricardo and Schmid, Hans-Joachim and Bieber, M. and Reddemann, M. and Kneer, R. and Fröde, F. and Grenga, T. and Pitsch, H.}}, location = {{Paderborn}}, title = {{{Einfluss der Zerstäubung auf die Partikelsynthese in Sprayflammen}}}, year = {{2021}}, } @misc{24202, author = {{Pawelczyk, Sebastian and Jesinghausen, Steffen and Schmid, Hans-Joachim}}, title = {{{Charakterisierung des Fließverhaltens von Frischbeton – Entwicklung eines adaptiven Rheometers (ACCR) und Einfluss von Maßnahmen zur Sedimentationsprävention}}}, year = {{2021}}, } @inproceedings{30225, author = {{Rüther, Moritz Johannes and Schulze, Dietmar and Schmid, Hans-Joachim}}, location = {{digital}}, title = {{{Flowability Measurements of Different SLS Materials at Elevated Temperatures with a Modified Schulze Ring Shear Tester}}}, year = {{2021}}, } @inproceedings{24160, abstract = {{In automotive and other fields of application media-carrying components often have complex, flow-optimized geometries and are made of plastics for reasons of weight and cost. Therefore, the laser sintering technology is predestinated to manufacture these components as it offers a very high degree of design freedom and good mechanical properties. For industrial applications the long-term properties of the SLS material in contact with liquid media are important and were therefore investigated for PA12, PP and PA613. Hereby, different media such as motor oil or Glysantin based coolant were tested with different temperatures and immersion times of up to 26 weeks. The mechanical properties were tested after immersion and compared to injection molded samples. Furthermore, laser sintering design guidelines for media-carrying components were developed. These guidelines for instance include the minimum wall thickness to ensure media tightness and the removal of powder from channels with a high length to diameter ratio.}}, author = {{Kletetzka, Ivo and Kummert, Christina and Schmid, Hans-Joachim}}, booktitle = {{Proceedings of the 32nd Annual International Solid Freeform Fabrication Symposium}}, location = {{Austin}}, publisher = {{Laboratory for Freeform Fabrication and University of Texas}}, title = {{{Laser Sintering Design Guidelines for media transmitting Components}}}, doi = {{http://dx.doi.org/10.26153/tsw/17548}}, volume = {{32}}, year = {{2021}}, } @article{26095, abstract = {{Luftreiniger werden derzeit häufig als mögliches Hilfsmittel zur Minimierung des Infektionsrisikos im Rahmen der COVID-19-Pandemie diskutiert. Dabei taucht oft die Frage auf, ob Luftreiniger grundsätzlich in der Lage sind, Viren oder virenbeladene Tröpfchen abzuscheiden. Ziel dieses Artikels ist es, die wesentlichen Grundlagen der Wirkungsweise von Luftreinigern und Filtern zu beschreiben, Methoden zur Messung der Reinigungswirkung im Größenbereich von Viren und virenbeladenen Tröpfchen aufzuzeigen sowie typische Szenarien zum Betrieb von Luftreinigern in einem mathematischen Modell zu erfassen. Darauf basierend können die Möglichkeiten und Grenzen von Luftreinigern für reale Anwendungsfälle besser eingeschätzt werden.}}, author = {{Schumacher, Stefan and Asbach, Christof and Schmid, Hans-Joachim}}, issn = {{0949-8036}}, journal = {{Gefahrstoffe}}, pages = {{16--28}}, title = {{{Effektivität von Luftreinigern zur Reduzierung des COVID-19-Infektionsrisikos/ Efficacy of air purifiers in reducing the risk of COVID-19 infections}}}, doi = {{10.37544/0949-8036-2021-01-02-18}}, year = {{2021}}, } @inproceedings{27553, author = {{Ludwig, Janis and Schmid, Hans-Joachim}}, title = {{{Synthese und asymmetrische Funktionalisierung von submikronen Janus-Polymer-Partikeln in der Gasphase (Poster)}}}, year = {{2021}}, } @inproceedings{24475, author = {{Neukötter, Moritz and Jesinghausen, Steffen and Schmid, Hans-Joachim}}, location = {{Online}}, title = {{{Theoretische Beschreibung des Tropfenbildungsprozesses bei der Filament Extension Atomization: Entwicklung eines Vorhersagemodells für die Tropfengröße (Poster)}}}, year = {{2021}}, } @inproceedings{30221, author = {{Neukötter, Moritz and Jesinghausen, Steffen and Schmid, Hans-Joachim}}, location = {{Online}}, title = {{{Filament Extension Atomization – A novel Process for Powder Production? (Presentation)}}}, year = {{2021}}, } @inproceedings{27551, author = {{Ludwig, Janis and Kykal, Carsten and Schmid, Hans-Joachim}}, booktitle = {{Book of abstracts for the 2021 European Aerosol Conference}}, keywords = {{aerosol spreading, SARS-CoV-2, indoor air filtration}}, title = {{{Assessing spreading and removal of virus laden aerosols in different settings using an aerosol method (oral presentation)}}}, year = {{2021}}, } @techreport{24943, author = {{Menge, Dennis and Klippstein, Sven Helge and Schmid, Hans-Joachim}}, pages = {{130}}, title = {{{Additive Leichtbaustrukturen für die Flugzeugkabine}}}, year = {{2020}}, }