@inproceedings{HartmannDobhanEngelmannetal., author = {Hartmann, J{\"u}rgen and Dobhan, Alexander and Engelmann, Bastian and Eberhardt, Lars and Heusinger, Moritz and Raab, C and Schleif, Frank-Michael and T{\"u}rk, M.}, title = {Optimierung von Prozessen und Werkzeugmaschinen durch Bereitstellung, Analyse und Soll-Ist-Vergleich von Produktionsdaten: Digitalkonferenz}, language = {en} } @article{HartmannThuillierFoujolsetal., author = {Hartmann, J{\"u}rgen and Thuillier, G. and Foujols, T. and Bols{\´e}e, D. and Gillotay, D. and Hers{\´e}, M. and Petermanns, W. and Decupyer, W. and Mandel, H. and Sperfeld, P. and Taubert, Dieter Richard}, title = {SOLAR/SOLSPEC}, series = {Solar Physics}, journal = {Solar Physics}, number = {257}, pages = {185 -- 213}, language = {en} } @article{HartmannAnhaltLoweetal., author = {Hartmann, J{\"u}rgen and Anhalt, Klaus and Lowe, D. and Machin, Graham and Sadli, M. and Yamada, Y.}, title = {Thermodynamic temperature determinations of Co-C, Pd-C Pt-C and Ru-C eutectic fixed-points cells}, series = {Metrologia}, volume = {43}, journal = {Metrologia}, number = {2}, pages = {78 -- 83}, language = {en} } @article{HartmannMachinBloembergenetal., author = {Hartmann, J{\"u}rgen and Machin, G. and Bloembergen, P. and Sadli, M. and Yamada, Y.}, title = {A concerted international project to establish high-temperature fixed-points for primary thermometry}, series = {International Journal of Thermophysics}, journal = {International Journal of Thermophysics}, number = {28}, pages = {1976 -- 1982}, language = {en} } @incollection{HartmannReichling, author = {Hartmann, J{\"u}rgen and Reichling, M.}, title = {Thermal transport in diamond}, series = {Properties and growth of diamond}, booktitle = {Properties and growth of diamond}, editor = {Nazar{\´e}, H. and Neves, A.J.}, publisher = {Institution of Electrical Engineers}, address = {London}, language = {en} } @article{HartmannSadliAnhaltetal., author = {Hartmann, J{\"u}rgen and Sadli, M. and Anhalt, Klaus and Schiller, S.}, title = {Thermal effects in the BB3200pg on M-C eutectic implementation}, series = {International Journal of Thermophysics}, journal = {International Journal of Thermophysics}, number = {30}, pages = {69 -- 76}, language = {en} } @article{Hartmann, author = {Hartmann, J{\"u}rgen}, title = {New Developments in High-Temperature Measurement Techniques}, series = {International Journal of Electrical and Computer Engineering Systems}, volume = {5}, journal = {International Journal of Electrical and Computer Engineering Systems}, number = {2}, pages = {63 -- 67}, language = {en} } @article{HartmannEngertFellmuthetal., author = {Hartmann, J{\"u}rgen and Engert, J. and Fellmuth, B. and Fischer, Joachim and Hollandt, J{\"o}rg and Tegeler, E. and Seidel, J.}, title = {Die internationale Temperaturskalen}, series = {PTB Mitteilungen}, volume = {117}, journal = {PTB Mitteilungen}, number = {3}, pages = {236 -- 242}, language = {de} } @article{HartmannFischerJohannsenetal., author = {Hartmann, J{\"u}rgen and Fischer, J. and Johannsen, U. and Werner, L.}, title = {Analytical model for the temperature dependence of the spectral responsivity of silicon}, series = {J. Opt. Soc. Am. B}, journal = {J. Opt. Soc. Am. B}, number = {18}, pages = {942 -- 947}, language = {en} } @article{HoefflinSauerSchiffleretal., author = {H{\"o}fflin, Dennis and Sauer, Christian and Schiffler, Andreas and Versch, Alexander and Hartmann, J{\"u}rgen}, title = {Active thermography for in-situ defect detection in laser powder bed fusion of metal}, series = {Journal of Manufacturing Processes}, volume = {131}, journal = {Journal of Manufacturing Processes}, publisher = {Elsevier BV}, issn = {1526-6125}, doi = {10.1016/j.jmapro.2024.09.085}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:863-opus-57601}, pages = {1758 -- 1769}, abstract = {Additive manufacturing (AM) has revolutionized production by offering design flexibility, reducing material waste, and enabling intricate geometries that are often unachievable with traditional methods. As the use of AM for metals continues to expand, it is crucial to ensure the quality and integrity of printed components. Defects can compromise the mechanical properties and performance of the final product. Non-destructive testing (NDT) techniques are necessary to detect and characterize anomalies during or post-manufacturing. Active thermography, a thermal imaging technique that uses an external energy source to induce temperature variations, has emerged as a promising tool in this field. This paper explores the potential of in-situ non-destructive testing using the processing laser of a PBF-LB/M setup as an excitation source for active thermography. With this technological approach, artificially generated internal defects underneath an intact surface can be detected down to a defect size of 350 μm - 450 μm.}, language = {en} } @article{HoefflinSauerSchiffleretal., author = {H{\"o}fflin, Dennis and Sauer, Christian and Schiffler, Andreas and Manara, Jochen and Hartmann, J{\"u}rgen}, title = {Pixelwise high-temperature calibration for in-situ temperature measuring in powder bed fusion of metal with laser beam}, series = {Heliyon}, volume = {10}, journal = {Heliyon}, number = {7}, publisher = {Elsevier BV}, issn = {2405-8440}, doi = {10.1016/j.heliyon.2024.e28989}, abstract = {High-temperature calibration methods in additive manufacturing involve the use of advanced techniques to accurately measure and control the temperature of the build material during the additive manufacturing process. Infrared cameras, blackbody radiation sources and non-linear optimization algorithms are used to correlate the temperature of the material with its emitted thermal radiation. This is essential for ensuring the quality and repeatability of the final product. This paper presents the calibration procedure of an imaging system for in-situ measurement of absolute temperatures and temperature gradients during powder bed fusion of metal with laser beam (PBF-LB/M) in the temperature range of 500 K-1500 K. It describes the design of the optical setup to meet specific requirements in this application area as well as the procedure for accounting the various factors influencing the temperature measurement. These include camera-specific effects such as varying spectral sensitivities of the individual pixels of the sensor as well as influences of the exposure time and the exposed sensor area. Furthermore, influences caused by the complex optical path, such as inhomogeneous transmission properties of the galvanometer scanner as well as angle-dependent transmission properties of the f-theta lens were considered. A two-step fitting algorithm based on Planck's law of radiation was applied to best represent the correlation. With the presented procedure the calibrated thermography system provides the ability to measure absolute temperatures under real process conditions with high accuracy.}, language = {en} } @misc{HoefflinSchifflerHartmannetal., author = {H{\"o}fflin, Dennis and Schiffler, Andreas and Hartmann, J{\"u}rgen and Sauer, Christian}, title = {Dual Scan head approach for in-situ defect detection in laser powder bed fusion of metals - Dataset}, doi = {10.5281/zenodo.15727369}, abstract = {This dataset contains thermographic data from a study on in-situ defect detection in the Laser Powder Bed Fusion of Metals (PBF-LB/M) process. The data was collected using a novel experimental setup named Synchronized Path Infrared Thermography (SPIT), which employs a dual scan head configuration. One scan head directs the processing laser, while the second scan head positions the measurement field of an infrared (IR) camera. This setup allows for the precise analysis of the cooling behavior of the material decoupled from the immediate laser-material interaction zone. The experiments were conducted on pre-fabricated stainless steel (EOS StainlessSteel PH1, DIN 14540) samples with embedded, cylindrical subsurface defects of varying diameters. A single layer of metal powder was applied to these samples and then fused by the laser. The dataset includes a series of measurements where process parameters, specifically the volumetric energy density and the laser scanning speed, were systematically varied to assess their influence on defect detection reliability. The provided data consists of raw thermographic recordings, which capture the surface temperature distribution in the heat-affected zone behind the melt pool. These recordings can be used to identify localized areas of elevated temperature caused by the insulating effect of the subsurface defects, which impede heat transfer into the substrate. This dataset is valuable for researchers working on process monitoring, defect detection algorithms, and the validation of thermal simulations in additive manufacturing.}, language = {en} } @misc{SauerSchifflerHoefflinetal., author = {Sauer, Christian and Schiffler, Andreas and H{\"o}fflin, Dennis and Hartmann, J{\"u}rgen}, title = {Temporally Gated Active Thermography for Defect Detection in Laser-Based Powder Bed Fusion of Metals - Dataset}, doi = {10.5281/zenodo.17747278}, abstract = {This HDF5-dataset contains in-situ high-speed infrared thermography data acquired during the Laser-Based Powder Bed Fusion (PBF-LB/M) process. The data was collected using a Synchronized Path Infrared Thermography (SPIT) setup, which employs a dual-scanhead configuration to guide both the processing laser and the thermal camera's field of view. The primary feature of this dataset is the application of a temporally gated acquisition strategy. The infrared camera's integration time (800 µs) was synchronized with a modulated processing laser (500 Hz) to capture thermal data exclusively during the laser-off phases. This method effectively isolates the material's thermal emission from high-intensity laser reflections.}, language = {en} } @incollection{HartmannRingAmmeretal., author = {Hartmann, J{\"u}rgen and Ring, E.F.J. and Ammer, K. and Land, D. and Thomas, R. and Hand, J.W.}, title = {Infrared and Microwave Medical Thermometry in Radiometric Temperature Measurements Part II}, series = {Experimental Methods in the Physical Sciences}, volume = {43}, booktitle = {Experimental Methods in the Physical Sciences}, editor = {Zhang, Z.M. and Tsai, B.K. and Machin, G.}, publisher = {Elsevier Academic Press}, address = {Amsterdam}, isbn = {978-0-12-375091-4}, pages = {393 -- 448}, language = {en} } @incollection{HartmannHollandtStrussetal., author = {Hartmann, J{\"u}rgen and Hollandt, J{\"o}rg and Struß, O. and Gaertner, R. and Ishii, J.}, title = {Industrial Applications of Radiation Thermometry, in Radiometric Temperature Measurements Part II}, series = {Experimental Methods in the Physical Sciences, Volume 43}, volume = {43}, booktitle = {Experimental Methods in the Physical Sciences, Volume 43}, editor = {Zhang, Z.M. and Tsai, B.K. and Machin, Graham}, publisher = {Elsevier Academic Press}, address = {Amsterdam}, isbn = {978-0-12-375091-4}, pages = {1 -- 56}, language = {en} } @article{HartmannEdler, author = {Hartmann, J{\"u}rgen and Edler, F.}, title = {Simultaneous contact and non-contact measurements of the melting temperature of a Ni-C fixed-point cell}, series = {International Journal of Thermophysics}, journal = {International Journal of Thermophysics}, number = {28}, pages = {2002 -- 2008}, language = {en} } @article{HartmannHollandtMeindletal., author = {Hartmann, J{\"u}rgen and Hollandt, J{\"o}rg and Meindl, P. and Taubert, Dieter Richard and Werner, L.}, title = {Traceable Radiometric Calibration of Semiconductor Detectors and their Application for Thermodynamic Temperature Measurement}, series = {MAPAN - Journal of Metrology Society of India}, volume = {25}, journal = {MAPAN - Journal of Metrology Society of India}, number = {3-10}, language = {de} } @article{HartmannEdler, author = {Hartmann, J{\"u}rgen and Edler, F.}, title = {Kombi-Fixpunktzelle zur Erzielung kleinster metrologischer Unsicherheiten}, series = {Sensor Magazin}, journal = {Sensor Magazin}, number = {1}, pages = {20 -- 21}, language = {de} } @article{HartmannKeawprasertAnhaltetal., author = {Hartmann, J{\"u}rgen and Keawprasert, T. and Anhalt, Klaus and Taubert, Dieter Richard}, title = {Monochromator-based Absolute Calibration of Radiation Thermometers}, series = {International Journal of Thermophysics}, journal = {International Journal of Thermophysics}, number = {32}, pages = {1697 -- 1706}, language = {en} } @article{HartmannAnhaltTaubertetal., author = {Hartmann, J{\"u}rgen and Anhalt, Klaus and Taubert, Dieter Richard and Hollandt, J{\"o}rg}, title = {Absolute radiometry for the MeP-K}, series = {International Journal of Thermophysics}, journal = {International Journal of Thermophysics}, number = {32}, pages = {1707 -- 1718}, language = {en} } @article{HartmannHollandtFriedrichetal., author = {Hartmann, J{\"u}rgen and Hollandt, J{\"o}rg and Friedrich, R. and Gutschwager, B. and Taubert, Dieter Richard}, title = {High-Accuracy Radiation Thermometry at the National Metrology Institute of Germany}, series = {High Temperatures - High Pressures}, volume = {35/36}, journal = {High Temperatures - High Pressures}, number = {4}, pages = {379 -- 415}, language = {en} } @article{Hartmann, author = {Hartmann, J{\"u}rgen}, title = {High-temperature measurement techniques for the application in photometry radiometry and thermometry}, series = {Physics Reports}, volume = {469}, journal = {Physics Reports}, pages = {205 -- 269}, language = {en} } @article{HartmannVoelker, author = {Hartmann, J{\"u}rgen and V{\"o}lker, S.}, title = {Thermal management of light sources}, series = {International Journal of Thermophysics}, journal = {International Journal of Thermophysics}, number = {32}, pages = {513 -- 522}, language = {en} } @article{HartmannHollandtGutschwageretal., author = {Hartmann, J{\"u}rgen and Hollandt, J{\"o}rg and Gutschwager, B. and Struss, O.}, title = {Strahlungsthermometrie}, series = {Automatisierungstechnische Praxis}, journal = {Automatisierungstechnische Praxis}, number = {6}, pages = {70 -- 81}, language = {de} } @article{HartmannHollandtAnhalt, author = {Hartmann, J{\"u}rgen and Hollandt, J{\"o}rg and Anhalt, Klaus}, title = {Radiation thermometry capabilities of the PTB up to 3200 K}, series = {MEASURE}, journal = {MEASURE}, number = {3}, pages = {26 -- 34}, language = {en} }