TY - JOUR A1 - Dreßler, Martin A1 - Röllig, Mathias A1 - Schmidt, Martin A1 - Maturilli, A. A1 - Helbert, J. T1 - Temperature distribution in powder beds during 3D printing N2 - Purpose – This purpose of this paper is to report about the temperature distribution in metal and ceramic powder beds during 3D printing. The differing powders are thoroughly characterized in terms of thermal conductivity, thermal diffusivity, emissivity spectra and density. Design/methodology/approach – The temperature distribution was measured in a 3D printing appliance (Prometal R1) with the help of thin thermocouples (0.25 mm diameter) and thermographic imaging. Temperatures at the powder bed surface as well as at differing powder bed depths were determined. The thermal conductivity, thermal diffusivity and emissivity spectra of the powders were measured as well. Numerical simulation was used to verify the measured temperatures. Findings – The ceramic powder heated up and cooled down more quickly. This finding corresponds well with numerical simulations based on measured values for thermal conductivity and thermal diffusivity as well as emissivity spectra. An observed color change at the metal powder has only little effect on emissivity in the relevant wavelength region. Research limitations/implications – It was found that thermocouple-based temperature measurements at the powder bed surface are difficult and these results should be considered with caution. Practical implications – The results give practitioners valuable information about the transient temperature evolution for two widely used but differing powder systems (metal, ceramic). The paramount importance of powder bed porosity for thermal conductivity was verified. Already small differences in thermal conductivity, thermal diffusivity and hence volumetric heat capacity lead to marked differences in the transient temperature evolution. Originality/value – The paper combines several techniques such as temperature measurements, spectral emissivity measurements, measurements of thermal conductivity and diffusivity and density measurements. The obtained results are put into a numerical model to check the obtained temperature data and the other measured values for consistency. This approach illustrates that determinations of surface temperatures of the powder beds are difficult. KW - Rapid prototypes KW - Printers KW - Heat transfer KW - Powders KW - Ceramics KW - Metals PY - 2010 DO - https://doi.org/10.1108/13552541011065722 SN - 1355-2546 VL - 16 IS - 5 SP - 328 EP - 336 PB - MCB University Press CY - Bradford AN - OPUS4-22002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Feigl, Michael A1 - Nofz, Marianne A1 - Sojref, Regine A1 - Dressler, Martin A1 - Pulz, Robert A1 - Rehmer, Birgit A1 - Feldmann, Ines A1 - Sabel, Martin T1 - Aluminiumoxidschichten für den Oxidationsschutz von Hochtemperaturlegierungen N2 - Effektive Al2O3-Keramik-Schutzschichten könnten die Verwendung preiswerterer Legierungen für Hochtemperaturanwendungen ermöglichen. Die Anforderungen an diese Schichten sind eine gute Haftung, chemische Stabilität und Dichtheit gegen die Umgebungsatmosphäre. T2 - DKG-Jahrestagung/Symposium Hochleistungskeramik CY - Aachen, Germany DA - 23.03.2009 KW - Schichtherstellung KW - Schichttestung KW - Hochtemperaturanwendungen PY - 2009 AN - OPUS4-35836 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dreßler, Martin A1 - Dombrowski, Felix A1 - Simon, Ulla A1 - Börnstein, Julian A1 - Hodoroaba, Vasile-Dan A1 - Feigl, Michael A1 - Grunow, Sabrina A1 - Gildenhaar, Renate A1 - Neumann, Martin T1 - Influence of gelatine coatings on compressive strength of porous hydroxyapatite ceramics N2 - Porous ceramics prepared by the foam replication technique have a high porosity and low mechanical stability. It has been reported that coating such porous ceramics with gelatin allows for an improved compressive strength. Little details regarding the influence of important gelatin parameters such as concentration, temperature and drying conditions as well as bloom number which is a measure of the gel rigidity, on this toughening effect are available. This paper investigates the influence of these parameters on compressive strength of gelatin coated porous hydroxyapatite ceramics. It was found that concentration in the gelatin sols has a marked impact whereas sol temperature, bloom number and differing conditions during subsequent drying have only little influence on the compressive strength of the coated ceramics. KW - Films KW - Composites KW - Strength KW - Apatite KW - Biomedical application PY - 2011 DO - https://doi.org/10.1016/j.jeurceramsoc.2010.11.004 SN - 0955-2219 SN - 1873-619X VL - 31 IS - 4 SP - 523 EP - 529 PB - Elsevier Ltd. CY - Oxford AN - OPUS4-23216 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dreßler, Martin T1 - Herstellung von Biokeramik mittels rapid prototyping T2 - Kooperationsforum "Generative Fertigungs-technologien" CY - Berlin, Germany DA - 2009-04-29 PY - 2009 AN - OPUS4-19679 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dreßler, Martin T1 - Bioceramics with bone-morphology T2 - bone tech 2008 CY - Hanover, Germany DA - 2008-11-07 PY - 2008 AN - OPUS4-17638 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dreßler, Martin T1 - Hochtemperatur Oxidationsschutz von INCONEL-718 T2 - Hannover Messe CY - Hanover, Germany DA - 2008-04-25 PY - 2008 AN - OPUS4-18097 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dreßler, Martin T1 - Keramische Schichten für den Oxidationsschutz T2 - EuroMold 2008 CY - Frankfurt am Main, Germany DA - 2008-12-03 PY - 2008 AN - OPUS4-18099 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dreßler, Martin A1 - Reinsch, Stefan A1 - Schadrack, Reinhard A1 - Benemann, Sigrid T1 - Burnout behavior of ceramic coated open cell polyurethane (PU) sponges N2 - Open cell rigid foams made from polyurethane (PU) are frequently used in ceramic processing for preparation of porous ceramics by the so-called replica technique. This work presents data regarding the PU burnout, shrinkage characteristics as well as the morphology of the ceramic coated PU sponges during heating up. Shrinkage of the ceramic coated PU sponges closely follows the mass loss due to PU decomposition. Two temperatures (i) 267 °C and (ii) 380 °C were identified at which PU decomposition reaches local maxima. Shrinkage measurements on ceramic coated PU sponges reveal that both PU decomposition stages lead to similar extends of shrinkage in the ceramic coated PU sponge. Differential thermal analysis (DTA) showed that the two decomposition related temperatures (267 and 380 °C) differ concerning the energy release. While the low-temperature signal is endothermic, an exothermic signal was detected at 380 °C. The morphology of the ceramic coated PU sponges was investigated with scanning electron microscopy (SEM) which gave insight into the formation of hollow ceramic struts-a well known feature of ceramics being prepared by the replica technique. KW - Polyurethane (PU) KW - Porous ceramics KW - Mass spectrometry KW - Thermal analysis PY - 2009 DO - https://doi.org/10.1016/j.jeurceramsoc.2009.07.025 SN - 0955-2219 SN - 1873-619X VL - 29 IS - 16 SP - 3333 EP - 3339 PB - Elsevier CY - Oxford AN - OPUS4-20092 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dreßler, Martin T1 - Generative Fertigungstechniken für die Biokeramik T2 - Tagung des AK Keramikbearbeitung am Institut für Werkzeugmaschinen und Fabrikbetrieb, Fachgebiet Werkzeugmaschinen und Fertigungstechnik der TU Berlin CY - Berlin, Germany DA - 2009-10-01 PY - 2009 AN - OPUS4-20203 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dreßler, Martin T1 - Erfahrungen und Vorgehensweise bei chemisch/ physikalischen Materialprüfungen T2 - Veranstaltungsreihe "Risikobasierte biologische Beurteilung und Sicherheitsprüfungen von Medizinprodukten" CY - Potsdam, Germany DA - 2009-10-15 PY - 2009 AN - OPUS4-20204 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dreßler, Martin T1 - Resorbable ceramics scaffolds with bone-like morphology T2 - Rapid Prototyping in Regenerative Medicine at the 4th Fraunhofer Life Science Symposium CY - Leipzig, Germany DA - 2009-10-29 PY - 2009 AN - OPUS4-20205 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nofz, Marianne A1 - Sojref, Regine A1 - Feigl, Michael A1 - Dreßler, Martin A1 - Dörfel, Ilona T1 - Sol-Gel-Aluminiumoxidschichten für den Oxidationsschutz von Hochtemperaturlegierungen, Teil 2 KW - Alumosol KW - Sol-Gel-Verfahren KW - Beschichtung KW - Oxidationsschutz PY - 2009 SN - 0023-0561 VL - 61 IS - 5 SP - 272 EP - 277 PB - DVS-Verl. CY - Düsseldorf AN - OPUS4-20263 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nofz, Marianne A1 - Sojref, Regine A1 - Feigl, Michael A1 - Dreßler, Martin A1 - Dörfel, Ilona T1 - Sol-Gel-Aluminiumoxidschichten für den Oxidationsschutz von Hochtemperaturlegierungen, Teil 1 KW - Alumosol KW - Sol-Gel-Verfahren KW - Beschichtung KW - Oxidationsschutz PY - 2009 SN - 0023-0561 VL - 61 IS - 2-3 SP - 82 EP - 86 PB - DVS-Verl. CY - Düsseldorf AN - OPUS4-20264 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -