@phdthesis{42128,
  author       = {{Pieper, Sven}},
  isbn         = {{978-3-8440-5879-6}},
  pages        = {{135}},
  publisher    = {{Shaker Verlag}},
  title        = {{{Confinement Induced Segregation Effects in Suspension Rheology}}},
  volume       = {{5}},
  year         = {{2018}},
}

@phdthesis{42130,
  author       = {{Grimm, Philipp}},
  pages        = {{201}},
  title        = {{{Entwicklung einer Prozesskette zum flüssig-flüssig Phasentransfer nanoskaliger Partikeln}}},
  year         = {{2018}},
}

@phdthesis{42131,
  author       = {{Dörmann, Michael}},
  pages        = {{175}},
  title        = {{{Zur Modellierung von Kapillarbrücken zwischen nanoskaligen Partikeln}}},
  year         = {{2018}},
}

@inbook{23759,
  author       = {{Menge, Dennis and Josupeit, Stefan and Delfs, Patrick  and Schmid, Hans-Joachim}},
  booktitle    = {{Additive Fertigung von Bauteilen und Strukturen}},
  editor       = {{Richard, Hans Albert and Schramm, Britta and Zipsner, Thomas}},
  isbn         = {{9783658177799}},
  pages        = {{105--120}},
  publisher    = {{Springer Vieweg}},
  title        = {{{Herstellbarkeit und mechanische Charakterisierung von lasergesinterten Gitterstrukturen}}},
  doi          = {{10.1007/978-3-658-17780-5}},
  year         = {{2017}},
}

@article{22195,
  abstract     = {{Polymer laser sintering (LS) is an important additive manufacturing (AM) technology. Individual and complex parts are directly produced from CAD data without the need of specific tools. The raw material is a polymer powder, which is deposited layerwise and melted selectively with a laser. Built parts are embedded in residual unmolten powder, the so-called part cake, which undergoes thermal ageing effects due to the exposure to high temperatures for long times during the manufacturing process. Hence, the recyclability of the unmolten powder is limited. This article focuses on a fundamental analysis of the ageing kinetics dependent on time, temperature, and oxygen content in the gas atmosphere. A model is developed and applied to measured, position-dependent process temperature histories to successfully predict the ageing distribution within a part cake. The results can be used to optimize the thermal process management in LS and to develop new efficient powder recycling methods. }},
  author       = {{Josupeit, Stefan and Schmid, Hans-Joachim}},
  journal      = {{Journal of Applied Polymer Science}},
  number       = {{42}},
  publisher    = {{Wiley}},
  title        = {{{Experimental analysis and modeling of local ageing effects during laser sintering of polyamide 12 in regard to individual thermal histories}}},
  doi          = {{10.1002/app.45435}},
  volume       = {{134}},
  year         = {{2017}},
}

@inproceedings{22421,
  author       = {{Lieneke, Tobias and Adam, Guido and Josupeit, Stefan and Delfs, Patrick and Zimmer, Detmar}},
  booktitle    = {{Proceedings of the 14th Rapid.Tech Conference}},
  isbn         = {{978-3-446-45460-6}},
  pages        = {{327--344}},
  publisher    = {{Hanser Verlag}},
  title        = {{{Maßtoleranzen für die additive Fertigung: Experimentelle Untersuchungen für das Lasersintern}}},
  doi          = {{10.3139/9783446454606.024 }},
  year         = {{2017}},
}

@phdthesis{21950,
  author       = {{Jesinghausen, Steffen}},
  isbn         = {{	978-3-8440-5600-6}},
  pages        = {{182}},
  publisher    = {{Shaker}},
  title        = {{{Rheo-PIV nichtkolloidaler Suspensionen: Strukturelle Untersuchungen der Strömungsentwicklung in Schlitzdüsen mit Fokus auf Wandgleiten}}},
  volume       = {{3}},
  year         = {{2017}},
}

@inproceedings{22180,
  abstract     = {{The implementation of lattice structures into additive manufactured parts is an important method to decrease part weight maintaining a high specific payload. However, the manufacturability of lattice structures and mechanical properties for polymer laser sintering are quite unknown yet. To examine the manufacturability, sandwich structures with different cell types, cell sizes and lattice bar widths were designed, manufactured and evaluated. A decisive criterion is for example a sufficient powder removal. In a second step, manufacturable structures were analyzed using four-point-bending tests. Experimental data is compared to the density of the lattice structures and allows for a direct comparison of different cell types with varied geometrical attributes. The results of this work are guidelines for the design and dimensioning of laser sintered lattice structures.}},
  author       = {{Josupeit, Stefan and Delfs, Patrick and Menge, Dennis and Schmid, Hans-Joachim}},
  booktitle    = {{27th Annual International Solid Freeform Fabrication Symposium }},
  pages        = {{2077--2086}},
  title        = {{{Manufacturability and Mechanical Characterization of Laser Sintered Lattice Structures}}},
  doi          = {{http://utw10945.utweb.utexas.edu/sites/default/files/2016/166-Josupeit.pdf}},
  volume       = {{27}},
  year         = {{2016}},
}

@article{22185,
  abstract     = {{The layered structure of Additive Manufacturing processes results in a stair- stepping effect of the surface topographies. In general, the impact of this effect strongly depends on the build angle of a surface, whereas the overall surface roughness is additionally caused by the resolution of the specific AM process. The aim of this work is the prediction of the surface quality in dependence of the building orientation of a part. These results can finally be used to optimize the orientation to get a desired surface quality. As not all parts of the component surface are equally important, a preselection of areas can be used to improve the overall surface quality of relevant areas. The model uses the digital AMF format of a part. Each triangle is assigned with a roughness value and by testing different orientations the best one can be found. This approach needs a database for the surface qualities. This must be done separately for each Additive Manufacturing process and is shown exemplarily with a surface topography simulation for the laser sintering process.}},
  author       = {{Delfs, Patrick and Tows, Marcel and Schmid, Hans-Joachim}},
  isbn         = {{2214-8604}},
  journal      = {{Additive Manufacturing}},
  number       = {{12, Part B}},
  pages        = {{214--320}},
  publisher    = {{Elsevier}},
  title        = {{{Optimized build orientation of additive manufactured parts for improved surface quality and build time}}},
  doi          = {{10.1016/j.addma.2016.06.003}},
  volume       = {{2}},
  year         = {{2016}},
}

@inproceedings{22190,
  author       = {{Delfs, Patrick and Schmid, Hans-Joachim}},
  booktitle    = {{Fraunhofer Direct Digital Manufacturing Conference}},
  isbn         = {{978-3-8396-1001-5}},
  pages        = {{411--414}},
  title        = {{{Extended Analysis of the Surface Topography of Laser Sintered Polymer Parts }}},
  doi          = {{https://www.bookshop.fraunhofer.de/buch/fraunhofer-direct-digital-manufacturing-conference-ddmc-2016/245111#}},
  volume       = {{3}},
  year         = {{2016}},
}

@inproceedings{22194,
  author       = {{Josupeit, Stefan and Schmid, Hans-Joachim}},
  booktitle    = {{International Congress on Particle Technology (PARTEC) }},
  title        = {{{Thermal properties of polyamide 12 powder for application in laser sintering}}},
  year         = {{2016}},
}

@inproceedings{22200,
  abstract     = {{In the polymer laser sinter process, part quality depends on many influencing factors along the process chain. For application of the technology in series production and an integration of laser sintered parts into a technical environment, the dimensional accuracy of parts has to be taken into account. Therefore, occuring deviatons and their scattering have to be reduced and homogenized based on process parameters and build job layout. In this work, the dimensional accuracy of laser sintered parts is analyzed for varied parameter values. Influences of different process and geometrical build job parameters on dimensional deviatons are figured out. The experimental results allow an evaluation of more and less important influences. Finally, measures are deduced to reduce and homogenize dimensional deviations.}},
  author       = {{Josupeit, Stefan and Delfs, Patrick and Lieneke, Tobias and Adam, Guido and Gessler, Monika and Pfisterer, H. and Schmid, Hans-Joachim}},
  booktitle    = {{Rapid Tech - International Trade Show & Conference for Additive Manufacturing }},
  isbn         = {{978-3-446-45060-8}},
  pages        = {{107--120}},
  title        = {{{Dimensional accuracy of polymer laser sintered parts: Influences and measures}}},
  doi          = {{10.3139/9783446450608.009}},
  year         = {{2016}},
}

@inproceedings{22408,
  author       = {{Josupeit, Stefan and Delfs, Patrick and Lieneke, Tobias and Schmid, Hans-Joachim}},
  booktitle    = {{27th Annual International Solid Freeform Fabrication Symposium }},
  title        = {{{Influences on the dimensional Accuracy of Laser Sintered Parts along the Process Chain}}},
  year         = {{2016}},
}

@article{21947,
  abstract     = {{Wall slip is a long-known phenomenon in the field of rheology. Nevertheless, the origin and the evolution are not completely clear yet. Regarding suspensions, the effect becomes even more complicated, because different mechanisms like pure slip or slip due to particle migration have to be taken into account. Furthermore, suspensions themselves show many flow anomalies and the isolation of slip is complicated. In order to develop working physical models, further insight is necessary. In this work, we measured experimentally the wall slip velocities of different highly filled suspensions in a rectangular slit die directly with respect to the particle concentration and the particle size. The slip velocities were obtained using a particle image velocimetry (PIV) system. The suspensions consisting of a castor oil–cinnamon oil blend and PMMA particles were matched in terms of refractive indexes to appear transparent. Hereby, possible optical path lengths larger than 15 mm were achieved. The slip velocities were found to be in a quadratic relation to the wall shear stress. Furthermore, the overall flow rate as well as the particle concentration has a direct influence on the slip. Concerning the shear stress, there seem to be two regions of slip with different physical characteristics. Furthermore, we estimated the slip layer thickness directly from the velocity profiles and propose a new interpretation. The PIV technique is used to investigate the viscosity and implicit the concentration profile in the slit die. It is shown that the particle migration process is quite fast.}},
  author       = {{Jesinghausen, Steffen and Weiffen, Rene and Schmid, Hans-Joachim}},
  issn         = {{0723-4864}},
  journal      = {{Experiments in Fluids}},
  keywords     = {{Rheology, Wall Slip, Slip, apparent slip, suspension}},
  title        = {{{Direct measurement of wall slip and slip layer thickness of non-Brownian hard-sphere suspensions in rectangular channel flows}}},
  doi          = {{10.1007/s00348-016-2241-6}},
  year         = {{2016}},
}

@phdthesis{40488,
  author       = {{Schiller, Sascha}},
  isbn         = {{978-3-8440-4342-6}},
  publisher    = {{Shaker Verlag}},
  title        = {{{Zur Feinstaubabscheidung aus Holzfeuerungsanlagen mit precoatierten Oberflächenfiltern}}},
  year         = {{2016}},
}

@article{25140,
  author       = {{Pieper, Sven and Schmid, Hans-Joachim}},
  issn         = {{0377-0257}},
  journal      = {{Journal of Non-Newtonian Fluid Mechanics}},
  pages        = {{1--7}},
  title        = {{{Layer-formation of non-colloidal suspensions in a parallel plate rheometer under steady shear}}},
  doi          = {{10.1016/j.jnnfm.2016.04.004}},
  year         = {{2016}},
}

@phdthesis{24751,
  abstract     = {{Das Thema der vorliegenden Dissertation ist die "Prozessqualifizierung zur verlässlichen Herstellung von Produkten im Polymer Lasersinterverfahren". Über eine definierte Qualitätsprozesskette werden sämtliche, auf die Produktqualität relevanten Einflussparameter, bestimmt und berücksichtigt. Unterschiedliche Methoden zur Materialcharakterisierung des pulverförmigen Ausgangsmaterials werden analysiert und bewertet. Rheologische sowie chemische Eigenschaften, aber auch die Partikelgrößenverteilung oder die Schüttdichte werden hinsichtlich Relevanz, Einfluss und Anwenderfreundlichkeit untersucht. Das Ziel ist eine sinnvolle Bestimmung des Ausgangszustandes des Pulvers anhand definierter, relevanter Materialeigenschaften, um reproduzierbare technische Bauteileigenschaften zu gewährleisten. Dazu werden mechanische, dynamisch-mechanische, physikalische, elektrische, thermische sowie chemische Untersuchungen durchgeführt und hinsichtlich wichtiger Einflussparameter evaluiert. Die Bestimmung erfolgt über entwickelte Referenzjobs, in denen die hauptsächlichen Einflussfaktoren auf das Polymer-Lasersinterverfahren entlang der Qualitätsprozesskette berücksichtigt werden. Die charakterisierten Daten dienen zur Auslegung eines fiktiven Produktes aus der Luftfahrtindustrie. Mit Hilfe dieser Methoden lassen sich Materialkennwerte für diverse Simulationstools eindeutig bestimmen um eine realitätsnahe Berechnung zu gewährleisten. }},
  author       = {{Rüsenberg, Stefan}},
  keywords     = {{Additive Fertigung, Polymere, Lasersintern, Methode, Qualität, Konstruktion, Eigenschaften, Material, Charakterisierung, Qualifizierung}},
  pages        = {{242}},
  publisher    = {{Shaker Verlag GmbH}},
  title        = {{{Prozessqualifizierung zur verlässlichen Herstellung von Produkten im Polymer Lasersinterverfahren}}},
  volume       = {{Band, 2}},
  year         = {{2015}},
}

@inproceedings{22178,
  author       = {{Delfs, Patrick and Li, Z. and Schmid, Hans-Joachim}},
  booktitle    = {{26th Annual International Solid Freeform Fabrication Symposium}},
  pages        = {{514--526}},
  title        = {{{Mass finishing of laser sintered parts}}},
  doi          = {{http://utw10945.utweb.utexas.edu/sites/default/files/2015/2015-41-Delfs.pdf}},
  volume       = {{26}},
  year         = {{2015}},
}

@inproceedings{22179,
  abstract     = {{The temperature distribution and history within laser sintered part cakes is an important aspect regarding the process quality and reproducibility of the polymer laser sintering process. Especially the temperature history during the build and cooling phase is decisive for powder ageing effects and the development of part quality characteristics. In this work, a measurement system for three-dimensional in-process temperature measurements is set up and the influence of different parameters on the inner part cake temperature distribution and history is analyzed. Important factors are not only geometrical build job parameters like the part packing density and build height, but also process parameters like the layer thickness and bulk powder density. Individual in-process temperature profiles at different positions within a part cake are finally correlated with powder ageing effects. The results of this work help to understand the temperature history dependency of powder and part properties and can therefore be used to develop optimized process controls.}},
  author       = {{Josupeit, Stefan and Schmid, Hans-Joachim}},
  booktitle    = {{26th Annual International Solid Freeform Fabrication Symposium}},
  pages        = {{190--199}},
  title        = {{{Temperature History within Laser Sintered Part Cakes and its Influence on Process Quality}}},
  doi          = {{http://utw10945.utweb.utexas.edu/sites/default/files/2015/2015-15-Josupeit.pdf}},
  volume       = {{26}},
  year         = {{2015}},
}

@inproceedings{22187,
  abstract     = {{Due to long process times at high temperatures, unmolten polyamide 12 material ages during the manufacturing process. Hence, it needs to be refreshed with new material for further build cycles. In application, refresh rates of about 50 % are commonly used. In this work, the recycling optimized material PA 2221 from EOS is analyzed along a series of 13 build and refresh cycles using a reduced refresh rate of 32 %. Before and after every build, the powder is analyzed regarding melt properties determined by MVR and DSC measurements. Thereby, in-process ageing effects are investigated and the steady-state conditions are determined accordingly. In addition, powder properties are directly linked to resulting mechanical and geometrical part properties. Key findings are a robust DSC measurement method for polyamide 12 powder, constant “circulated” material properties after three build/refresh cycles and robust tensile properties along the whole tested powder life cycle. As a result, process conditions of PA 2221 using reduced refresh rates can be derived from this work.}},
  author       = {{Josupeit, Stefan and Lohn, Johannes and Hermann, E. and Gessler, Monika and Tenbrink, S. and Schmid, Hans-Joachim}},
  booktitle    = {{26th Annual International Solid Freeform Fabrication Symposium}},
  pages        = {{540--549}},
  title        = {{{Material Properties of Laser Sintered Polyamide 12 as Function of Build Cycles Using Low Refresh Rates}}},
  doi          = {{http://utw10945.utweb.utexas.edu/sites/default/files/2015/2015-43-Josupeit.pdf}},
  volume       = {{26}},
  year         = {{2015}},
}