@inproceedings{KernSchifflerNordmannetal., author = {Kern, S and Schiffler, Andreas and Nordmann, R and Abele, Eberhard}, title = {Modelling and active damping of a motor spindle with speed-dependent dynamics}, series = {Proceedings of the 9th International Conference on Vibrations in Rotating Machinery, Exeter, UK}, booktitle = {Proceedings of the 9th International Conference on Vibrations in Rotating Machinery, Exeter, UK}, pages = {8 -- 10}, language = {en} } @inproceedings{AbeleSielaffSchiffleretal., author = {Abele, Eberhard and Sielaff, T and Schiffler, Andreas and Rothenb{\"u}cher, Stefan}, title = {Analyzing energy consumption of machine tool spindle units and identification of potential for improvements of efficiency}, series = {Glocalized Solutions for Sustainability in Manufacturing: Proceedings of the 18th CIRP International Conference on Life Cycle Engineering, Technische Universit{\"a}t Braunschweig, Braunschweig, Germany, May 2nd-4th, 2011}, booktitle = {Glocalized Solutions for Sustainability in Manufacturing: Proceedings of the 18th CIRP International Conference on Life Cycle Engineering, Technische Universit{\"a}t Braunschweig, Braunschweig, Germany, May 2nd-4th, 2011}, pages = {280 -- 285}, language = {en} } @inproceedings{AbeleKreisSchiffler, author = {Abele, Eberhard and Kreis, M and Schiffler, Andreas}, title = {Online diagnosis and identification of high accuracy HSC machining centers}, series = {6th International Conference on High Speed Machining}, booktitle = {6th International Conference on High Speed Machining}, pages = {1 -- 8}, language = {en} } @misc{SeyboldWegnerGluecketal., author = {Seybold, Alexander and Wegner, Christoph and Gl{\"u}ck, Stefan and Schiffler, Andreas and Voll, Martin}, title = {Measuring system for monitoring a spindle (Patent, US-20210187684-A1)}, language = {en} } @misc{Schiffler, author = {Schiffler, Andreas}, title = {Messsystem und Messverfahren zur Messung einer Oberfl{\"a}chendehnung mittels eines plasmonischen Reflektors (Patent, DE102013219149A1)}, language = {en} } @misc{Schiffler, author = {Schiffler, Andreas}, title = {Elektronikmodulanordnung zum Einbau in einen zylindrischen Bauraum sowie W{\"a}lzlageranordnung (Patent, DE102015202129A1)}, language = {en} } @misc{SchifflerGierlHeim, author = {Schiffler, Andreas and Gierl, Jurgen and Heim, Jens}, title = {Rolling bearing comprising an electric circuit, and method for producing an electric circuit for a rolling bearing (Patent, US-10077809-B2)}, language = {en} } @misc{Schiffler, author = {Schiffler, Andreas}, title = {Ringf{\"o}rmiges Verbindungselement zum elektrischen und mechanischen Verbinden von Elektronikmodulen, Elektronikmodulanordnung zum Einbau in einen zylindrischen Bauraum sowie W{\"a}lzlageranordnung (Patent, DE102015202126A1)}, language = {de} } @misc{HeimMenschSchiffler, author = {Heim, Jens and Mensch, Sergej and Schiffler, Andreas}, title = {Connecting element having a recessed portion on top of one end and a recessed portion on bottom of the other end (Patent, US-9972956-B2)}, language = {en} } @misc{Schiffler, author = {Schiffler, Andreas}, title = {Verbindungselement zum elektrischen und mechanischen Verbinden von Elektronikmodulen, Elektronikmodulanordnung zum Einbau in einen zylindrischen Bauraum sowie W{\"a}lzlageranordnung (Patent, DE102015202127A1)}, language = {de} } @misc{Schiffler, author = {Schiffler, Andreas}, title = {W{\"a}lzlager mit einer elektrischen Schaltung sowie Herstellungsverfahren einer elektrischen Schaltung f{\"u}r ein W{\"a}lzlager (Patent, DE102014217787A1)}, language = {en} } @misc{Schiffler, author = {Schiffler, Andreas}, title = {Schmiermittelversorgungseinheit f{\"u}r ein W{\"a}lzlager (Patent, DE102012221439B4)}, language = {en} } @misc{Schiffler, author = {Schiffler, Andreas}, title = {Radialw{\"a}lzlager, insbesondere Spindellager (Patent, DE102013213685A1)}, language = {en} } @misc{Schiffler, author = {Schiffler, Andreas}, title = {Schmiervorrichtung f{\"u}r ein Lager (Patent, WO/2014/048594)}, language = {en} } @article{MillerCeballosEngelmannetal., author = {Miller, Eddi and Ceballos, Hector and Engelmann, Bastian and Schiffler, Andreas and Batres, Rafael and Schmitt, Jan}, title = {Industry 4.0 and International Collaborative Online Learning in a Higher Education Course on Machine Learning}, series = {2021 Machine Learning-Driven Digital Technologies for Educational Innovation Workshop}, journal = {2021 Machine Learning-Driven Digital Technologies for Educational Innovation Workshop}, pages = {1 -- 8}, language = {en} } @article{SchmittSauerHoefflinetal., author = {Schmitt, Anna-Maria and Sauer, Christian and H{\"o}fflin, Dennis and Schiffler, Andreas}, title = {Powder Bed Monitoring Using Semantic Image Segmentation to Detect Failures during 3D Metal Printing}, series = {Sensors}, volume = {23}, journal = {Sensors}, number = {9}, publisher = {MDPI}, doi = {10.3390/s23094183}, pages = {4183 -- 4183}, abstract = {Monitoring the metal Additive Manufacturing (AM) process is an important task within the scope of quality assurance. This article presents a method to gain insights into process quality by comparing the actual and target layers. Images of the powder bed were captured and segmented using an Xception-style neural network to predict the powder and part areas. The segmentation result of every layer is compared to the reference layer regarding the area, centroids, and normalized area difference of each part. To evaluate the method, a print job with three parts was chosen where one of them broke off and another one had thermal deformations. The calculated metrics are useful for detecting if a part is damaged or for identifying thermal distortions. The method introduced by this work can be used to monitor the metal AM process for quality assurance. Due to the limited camera resolutions and inconsistent lighting conditions, the approach has some limitations, which are discussed at the end.}, language = {en} } @article{WehnertOchsSchmittetal., author = {Wehnert, Kira-Kristin and Ochs, Dennis and Schmitt, Jan and Hartmann, J{\"u}rgen and Schiffler, Andreas}, title = {Reducing Lifecycle Costs due to Profile Scanning of the Powder Bed in Metal Printing}, series = {Procedia CIRP 98}, volume = {98}, journal = {Procedia CIRP 98}, publisher = {Elsevir}, pages = {684 -- 689}, abstract = {First time right is one major goal in powder based 3D metal printing. Reaching this goal is driven by reducing life cycle costs for quality measures, to minimize scrap rate and to increase productivity under optimal resource efficiency. Therefore, monitoring the state of the powder bed for each printed layer is state of the art in selective laser melting. In the most modern approaches the quality monitoring is done by computer vision systems working with an interference on trained neural networks with images taken after exposure and after recoating. There are two drawbacks of this monitoring method: First, the sensor signals - the image of the powder bed - give no direct height information. Second, the application of this method needs to be trained and labeled with reference images for several cases. The novel approach presented in this paper uses a laser line scanner attached to the recoating machine. With this new concept, a direct threshold measure can be applied during the recoating process to detect deviations in height level without prior knowledge. The evaluation can be done online during recoating and feedback to the controller to monitor each individual layer. Hence, in case of deviations the location in the printing plane is an inherent measurement and will be used to decide which severity of error is reported. The signal is used to control the process, either by starting the recoating process again or stopping the printing process. With this approach, the sources of error for each layer can be evaluated with deep information to evaluate the cause of the error. This allows a reduction of failure in the future, which saves material costs, reduces running time of the machine life cycle phase in serial production and results in less rework for manufactured parts. Also a shorter throughput time per print job results, which means that the employee can spent more time to other print jobs and making efficient use of the employee's work force. In summary, this novel approach will not only reduce material costs but also operating costs and thus optimize the entire life cycle cost structure. The paper presents a first feasibility and application of the described approach for test workpieces in comparison to conventional monitoring systems on an EOS M290 machine.}, language = {en} } @article{OchsWehnertHartmannetal., author = {Ochs, Dennis and Wehnert, Kira-Kristin and Hartmann, J{\"u}rgen and Schiffler, Andreas and Schmitt, Jan}, title = {Sustainable Aspects of a Metal Printing Process Chain with Laser Powder Bed Fusion (LPBF)}, series = {Procedia CIRP}, volume = {98}, journal = {Procedia CIRP}, publisher = {Elsevir}, pages = {613 -- 618}, abstract = {Production companies are getting more and more aware of the relevancy of energy costs and the environmental impact of their manufactured products. Hence, the knowledge about the energy intensity of new process technologies as metal printing becomes increasingly crucial. Therefore, data about the energy intensity of entire process chains allow a detailed assessment of the life cycle costs and environmental impact of metal printed parts. As metal printing with Laser Powder Bed Fusion (LPBF) is applied from rapid prototyping to serial manufacturing processes more and more, sustainability data are useful to support a valid scale-up scenario and energetic improvements of the 3D-printing machinery as well as peripheral aggregates used in the process chain. The contribution aims to increase the transparency of the LPBF process chain in terms of its energy consumption. Therefore a generalized model to assess sustainability aspects of metal printed parts is derived. For this purpose, the LPBF process chain with the essential pre-, main- and post-processes is evaluated regarding its energy intensity. Here, the sub-processes, for example wet and dry cleaning of the printer, sieving of the metal powder or sand-blasting of the part are analyzed as well as the main printing process. Based on the derived experimental data from an installed, industry-like process chain, a model is created, which tends to generalize the experimental findings to evaluate other metal printed parts and process chain variants in terms of their energy intensity.}, language = {en} } @article{OchsWehnertKnoppetal., author = {Ochs, Dennis and Wehnert, Kira-Kristin and Knopp, Kevin and Hartmann, J{\"u}rgen and Versch, Alexander and Schiffler, Andreas}, title = {Untersuchungen zur Temperaturleitf{\"a}higkeit additiv gefertigter Stahlproben in Abh{\"a}ngigkeit der relativen Dichte}, series = {FHWS Science Journal}, volume = {5}, journal = {FHWS Science Journal}, number = {2}, issn = {2196-6095}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:863-opus-19986}, pages = {75 -- 82}, abstract = {Das direkte Metall-Laser-Schmelzen (DMLS) aus der Familie der Additiven Fertigungsverfahren (AM) erm{\"o}glicht die schichtweise Erzeugung komplexer dreidimensionaler Geometrien mit hoher relativer Dichte unter Verwendung von Metallpulver als Ausgangsmaterial [1]. Die Technologie wird zunehmend eingesetzt, um innovative Bauteile material- und gewichtssparend herzustellen oder komplexe Produkte ohne zus{\"a}tzliche Werkzeuge oder Spannvorrichtungen zu fertigen. Dar{\"u}ber hinaus sind Funktionsintegrationen, zum Beispiel Gussformen mit eingepr{\"a}gten K{\"u}hlkan{\"a}len, m{\"o}glich. Da einzelne Metallpulverschichten auf vorhergehende Schichten aufgeschmolzen werden, entstehen w{\"a}hrend der Herstellung des Bauteils komplexe, zeitabh{\"a}ngige Temperaturprofile [2]. Durch den Einsatz hoher Laserintensit{\"a}ten und Scangeschwindigkeiten, bei denen die Belichtungszeit der Laserbestrahlung im Bereich von Millisekunden liegt, werden zudem extrem hohe Aufheiz- und Abk{\"u}hlraten induziert, die zu einzigartigen Mikrostrukturen und Materialeigenschaften f{\"u}hren [3]. Diese extremen Prozessbedingungen k{\"o}nnen sich jedoch auch negativ auf den Fertigungsprozess auswirken. Bei komplexen Bauteilen bleibt die Prozessstabilit{\"a}t und Qualit{\"a}tssicherung Umfragen zufolge weiterhin die wichtigste technologische Barriere f{\"u}r den Einsatz additiv gefertigter Bauteile in hochbelasteten oder sicherheitsrelevanten Bereichen [4]. Daher verspricht der Zusammenhang zwischen Temperaturprofil w{\"a}hrend der Fertigung, relativer Dichte der Bauteile, sowie thermophysikalischer Eigenschaften additiv gefertigter Proben wichtige Erkenntnisse, insbesondere im Hinblick auf eine zerst{\"o}rungsfreie Qualit{\"a}tssicherung, sowie neue Anwendungsm{\"o}glichkeiten.}, language = {de} } @article{SchifflerWehnertOchs, author = {Schiffler, Andreas and Wehnert, Kira-Kristin and Ochs, Dennis}, title = {Einsatz einer maschinell gelernten Bildsegmentierung zur Pulverbett{\"u}berwachung im Metalldruck}, series = {FHWS Science Journal}, volume = {5}, journal = {FHWS Science Journal}, number = {2}, issn = {2196-6095}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:863-opus-20021}, pages = {147 -- 152}, abstract = {Der Schwerpunkt der folgenden Ausf{\"u}hrungen ist auf eine schichtweise Erkennung von Abweichungen durch die automatisierte Analyse von Bilddaten aus pulverbettbasierten Metalldruckprozessen gelegt. Bei diesen Prozessen wird eine d{\"u}nne Schicht im Bereich von 20 bis 100 μm aus pulverf{\"o}rmigem Metallpulver aufgetragen. Ein zweidimensionaler Querschnitt des gew{\"u}nschten Bauteils wird dann entweder mit einer selektiven W{\"a}rmequelle aufgeschmolzen oder mit einem Bindemittel zusammengebunden. Anschließend wird das Substrat um die H{\"o}he einer Pulverschicht abgesenkt und der Vorgang wiederholt, bis der Aufbau abgeschlossen ist. Nach dem Abschluss des Aufschmelzens einer Schicht wird ein Bild mittels einer Kamera im sichtbaren Wellenl{\"a}ngenbereich erstellt. Abbildung 1 zeigt zwei Beispiele solcher Bilder. Diese bilden die Eingangsgr{\"o}ße f{\"u}r die Erkennung von Abweichungen. Durch die gew{\"a}hlte Schichtdicke kann die Herstellung eines Bauteils mehrere tausend Bilder erzeugen. Die automatisierte und zeitnahe Auswertung ist daher Inhalt aktueller Forschungs- und Entwicklungsaktivit{\"a}ten [1]. Nicht zuletzt da die notwendige Sensorik - eine Kamera - wirtschaftlich und robust einsetzbar ist.}, language = {de} }