TY - JOUR A1 - Abbas, Karim A1 - Balc, Nicolae A1 - Bremen, Sebastian A1 - Skupin, Marco T1 - Crystallization and aging behavior of polyetheretherketone PEEK within rapid tooling and rubber molding JF - Journal of Manufacturing and Materials Processing N2 - In times of short product life cycles, additive manufacturing and rapid tooling are important methods to make tool development and manufacturing more efficient. High-performance polymers are the key to mold production for prototypes and small series. However, the high temperatures during vulcanization injection molding cause thermal aging and can impair service life. The extent to which the thermal stress over the entire process chain stresses the material and whether it leads to irreversible material aging is evaluated. To this end, a mold made of PEEK is fabricated using fused filament fabrication and examined for its potential application. The mold is heated to 200 ◦C, filled with rubber, and cured. A differential scanning calorimetry analysis of each process step illustrates the crystallization behavior and first indicates the material resistance. It shows distinct cold crystallization regions at a build chamber temperature of 90 ◦C. At an ambient temperature above Tg, crystallization of 30% is achieved, and cold crystallization no longer occurs. Additional tensile tests show a decrease in tensile strength after ten days of thermal aging. The steady decrease in recrystallization temperature indicates degradation of the additives. However, the tensile tests reveal steady embrittlement of the material due to increasing crosslinking. KW - additive manufacturing KW - fused filament fabrication KW - crystallization KW - polyetheretherketone KW - rapid tooling Y1 - 2022 U6 - https://doi.org/10.3390/jmmp6050093 SN - 2504-4494 N1 - The article belongs to the Special Issue Advances in Injection Molding: Process, Materials and Applications VL - 6 IS - 5 SP - 1 EP - 12 PB - MDPI CY - Basel ER - TY - JOUR A1 - Ziebura, Dawid A1 - Bremen, Sebastian A1 - Schleifenbaum, Johannes Henrich A1 - Gebhardt, Andreas T1 - Machbarkeitsstudie zur Verarbeitung von nicht rostendem Stahl 1.4404 unter Verwendung einer Diodenlaser-basierten LPBF-Maschine mit kartesischem Achssystem JF - RTejournal - Forum für Rapid Technologie Y1 - 2018 SN - 1614-0923 VL - 15 ER - TY - JOUR A1 - Fateri, Miranda A1 - Gebhardt, Andreas A1 - Thümmler, Stefan A1 - Thurn, Laura T1 - Experimental investigation on selective laser melting of glass JF - Physics procedia : 8th International Conference on Laser Assisted Net Shape Engineering LANE 2014 Y1 - 2014 U6 - https://doi.org/10.1016/j.phpro.2014.08.118 SN - 1875-3892 (E-Journal); 1875-3884 (Print) VL - 56 (2014) SP - 357 EP - 364 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Luft, Angela A1 - Bremen, Sebastian A1 - Luft, Nils T1 - A cost/benefit and flexibility evaluation framework for additive technologies in strategic factory planning JF - Processes N2 - There is a growing demand for more flexibility in manufacturing to counter the volatility and unpredictability of the markets and provide more individualization for customers. However, the design and implementation of flexibility within manufacturing systems are costly and only economically viable if applicable to actual demand fluctuations. To this end, companies are considering additive manufacturing (AM) to make production more flexible. This paper develops a conceptual model for the impact quantification of AM on volume and mix flexibility within production systems in the early stages of the factory-planning process. Together with the model, an application guideline is presented to help planners with the flexibility quantification and the factory design process. Following the development of the model and guideline, a case study is presented to indicate the potential impact additive technologies can have on manufacturing flexibility Within the case study, various scenarios with different production system configurations and production programs are analyzed, and the impact of the additive technologies on volume and mix flexibility is calculated. This work will allow factory planners to determine the potential impacts of AM on manufacturing flexibility in an early planning stage and design their production systems accordingly. KW - additive manufacturing KW - factory planning KW - manufacturing flexibility KW - volume flexibility KW - mix flexibility Y1 - 2023 U6 - https://doi.org/10.3390/pr11071968 SN - 2227-9717 VL - 11 IS - 7 PB - MDPI CY - Basel ER - TY - JOUR A1 - Haag, S. A1 - Zontar, D. A1 - Schleupen, Josef A1 - Müller, T. A1 - Brecher, C. T1 - Chain of refined perception in self-optimizing assembly of micro-optical systems JF - Journal of sensors and sensor systems N2 - Today, the assembly of laser systems requires a large share of manual operations due to its complexity regarding the optimal alignment of optics. Although the feasibility of automated alignment of laser optics has been shown in research labs, the development effort for the automation of assembly does not meet economic requirements – especially for low-volume laser production. This paper presents a model-based and sensor-integrated assembly execution approach for flexible assembly cells consisting of a macro-positioner covering a large workspace and a compact micromanipulator with camera attached to the positioner. In order to make full use of available models from computer-aided design (CAD) and optical simulation, sensor systems at different levels of accuracy are used for matching perceived information with model data. This approach is named "chain of refined perception", and it allows for automated planning of complex assembly tasks along all major phases of assembly such as collision-free path planning, part feeding, and active and passive alignment. The focus of the paper is put on the in-process image-based metrology and information extraction used for identifying and calibrating local coordinate systems as well as the exploitation of that information for a part feeding process for micro-optics. Results will be presented regarding the processes of automated calibration of the robot camera as well as the local coordinate systems of part feeding area and robot base. Y1 - 2014 U6 - https://doi.org/10.5194/jsss-3-87-2014 SN - 2194-878X VL - 3 IS - 1 SP - 87 EP - 95 PB - Copernicus Publ. CY - Göttingen ER - TY - JOUR A1 - Rieper, Harald A1 - Gebhardt, Andreas A1 - Stucker, Brent T1 - Selective Laser Melting of the Eutectic Silver-Copper Alloy Ag 28 wt % Cu JF - RTejournal - Forum für Rapid Technologie N2 - The aim of this work was to perform a detailed investigation of the use of Selective Laser Melting (SLM) technology to process eutectic silver-copper alloy Ag 28 wt. % Cu (also called AgCu28). The processing occurred with a Realizer SLM 50 desktop machine. The powder analysis (SEM-topography, EDX, particle distribution) was reported as well as the absorption rates for the near-infrared (NIR) spectrum. Microscope imaging showed the surface topography of the manufactured parts. Furthermore, microsections were conducted for the analysis of porosity. The Design of Experiments approach used the response surface method in order to model the statistical relationship between laser power, spot distance and pulse time. KW - SLM KW - Response Surface Method KW - Porositat KW - Eutectic Silver Copper alloy KW - Additive Manufacturing Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?nbn:de:0009-2-44141 SN - 1614-0923 VL - 13 ER - TY - JOUR A1 - Wollert, Jörg T1 - TSN – Schluss mit dem Feldbuskrieg? JF - Design & Elektronik Y1 - 2018 SN - 0933-8667 N1 - Echtzeit für Industrie 4.0. - Teil 3 IS - 3 SP - 26 EP - 31 PB - WEKA-Fachmedien CY - München ER - TY - JOUR A1 - Michaux, F. A1 - Mattern, P. A1 - Kallweit, Stephan T1 - RoboPIV: how robotics enable PIV on a large industrial scale JF - Measurement Science and Technology N2 - This work demonstrates how the interaction between particle image velocimetry (PIV) and robotics can massively increase measurement efficiency. The interdisciplinary approach is shown using the complex example of an automated, large scale, industrial environment: a typical automotive wind tunnel application. Both the high degree of flexibility in choosing the measurement region and the complete automation of stereo PIV measurements are presented. The setup consists of a combination of three robots, individually used as a 6D traversing unit for the laser illumination system as well as for each of the two cameras. Synchronised movements in the same reference frame are realised through a master-slave setup with a single interface to the user. By integrating the interface into the standard wind tunnel management system, a single measurement plane or a predefined sequence of several planes can be requested through a single trigger event, providing the resulting vector fields within minutes. In this paper, a brief overview on the demands of large scale industrial PIV and the existing solutions is given. Afterwards, the concept of RoboPIV is introduced as a new approach. In a first step, the usability of a selection of commercially available robot arms is analysed. The challenges of pose uncertainty and importance of absolute accuracy are demonstrated through comparative measurements, explaining the individual pros and cons of the analysed systems. Subsequently, the advantage of integrating RoboPIV directly into the existing wind tunnel management system is shown on basis of a typical measurement sequence. In a final step, a practical measurement procedure, including post-processing, is given by using real data and results. Ultimately, the benefits of high automation are demonstrated, leading to a drastic reduction in necessary measurement time compared to non-automated systems, thus massively increasing the efficiency of PIV measurements. Y1 - 2018 U6 - https://doi.org/10.1088/1361-6501/aab5c1 SN - 1361-6501 N1 - Special Section on the 12th International Symposium on Particle Image Velocimetry (PIV 2017) VL - 29 IS - 7 SP - 074009 PB - IOP CY - Bristol ER - TY - JOUR A1 - Wollert, Jörg T1 - Echtzeit-Ethernet – Basis für Industrie 4.0 JF - Design & Elektronik Y1 - 2018 SN - 0933-8667 N1 - Echtzeit für Industrie 4.0. - Teil 2 PB - WEKA-Fachmedien CY - München ER - TY - JOUR A1 - Kunkel, Maximilian Hugo A1 - Gebhardt, Andreas A1 - Mpofu, Khumbaulani A1 - Kallweit, Stephan T1 - Statistical assessment of mechanical properties of selective laser melted specimens of stainless steel JF - The International Journal of Advanced Manufacturing Technology N2 - The rail business is challenged by long product life cycles and a broad spectrum of assembly groups and single parts. When spare part obsolescence occurs, quick solutions are needed. A reproduction of obsolete parts is often connected to long waiting times and minimum lot quantities that need to be purchased and stored. Spare part storage is therefore challenged by growing stocks, bound capital and issues of part ageing. A possible solution could be a virtual storage of spare parts which will be 3D printed through additive manufacturing technologies in case of sudden demand. As mechanical properties of additive manufactured parts are neither guaranteed by machine manufacturers nor by service providers, the utilization of this relatively young technology is impeded and research is required to address these issues. This paper presents an examination of mechanical properties of specimens manufactured from stainless steel through the selective laser melting (SLM) process. The specimens were produced in multiple batches. This paper interrogates the question if the test results follow a normal distribution pattern and if mechanical property predictions can be made. The results will be put opposite existing threshold values provided as the industrial standard. Furthermore, probability predictions will be made in order to examine the potential of the SLM process to maintain state-of-the-art mechanical property requirements. Y1 - 2018 U6 - https://doi.org/10.1007/s00170-018-2040-8 SN - 0268-3768 VL - 98 IS - 5-8 SP - 1409 EP - 1431 PB - Springer CY - London ER - TY - JOUR A1 - Wingens, Niklas A1 - May, Jörg A1 - Pfaff, Raphael T1 - Betrieblich-technische Innovationsansätze zur Bremsprobe nach einer Prozessänderung JF - Eisenbahntechnische Rundschau : ETR ; Zeitschrift für die gesamte Eisenbahntechnik Y1 - 2019 SN - 0013-2845 IS - 5 PB - DVV Media Group CY - Hamburg ER - TY - JOUR A1 - Thomas, Axel T1 - Die Wiederbelebung der Mitarbeiterwohnungsidee bei kommunalen Unternehmen JF - VM Verwaltung und Management Y1 - 2019 U6 - https://doi.org/10.5771/0947-9856-2019-6-286 SN - 0947-9856 VL - 25 IS - 6 SP - 286 EP - 291 PB - Nomos-Verl.-Ges. CY - Baden-Baden ER - TY - JOUR A1 - Wilbring, Daniela A1 - Enning, Manfred T1 - Stromversorgung auf Güterwagen - Aktuelle Bemühungen zur Standardisierung JF - ETR - Eisenbahntechnische Rundschau Y1 - 2019 SN - 0013-2845 VL - 68 IS - 11 SP - 64 EP - 67 PB - DVV Media Group CY - Hamburg ER - TY - JOUR A1 - Wollbrink, Moritz A1 - Maslo, Semir A1 - Zimmer, Daniel A1 - Abbas, Karim A1 - Arntz, Kristian A1 - Bergs, Thomas T1 - Clamping and substrate plate system for continuous additive build-up and post-processing of metal parts JF - Procedia CIRP N2 - The manufacturing share of laser powder bed fusion (L-PBF) increases in industrial application, but still many process steps are manually operated. Additionally, it is not possible to achieve tight dimensional tolerances or low surfaces roughness. Hence, a process chain has to be set up to combine additive manufacturing (AM) with further machining technologies. To achieve a continuous workpiece flow as basis for further industrialization of L-PBF, the paper presents a novel substrate system and its application on L-PBF machines and post-processing. The substrate system consists of a zero-point clamping system and a matrix-like interface of contact pins to be substantially connected to the workpiece within the L-PBF process. Y1 - 2020 U6 - https://doi.org/10.1016/j.procir.2020.04.015 SN - 2212-8271 VL - 93 SP - 108 EP - 113 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ulmer, Jessica A1 - Gröninger, Marc A1 - Braun, Sebastian A1 - Wollert, Jörg T1 - AR Arbeitsplätze: Für hochflexible und skalierbare Produktionsumgebungen JF - atp Magazin N2 - Trotz fortschreitender Automatisierung bleiben manuelle Tätigkeiten ein wichtiger Baustein der Fertigung kundenindividueller Produkte. Um die Mitarbeiter(innen) zu unterstützen und um eine effiziente Arbeit zu ermöglichen, werden zunehmend auf Augmented Reality (AR) basierende Systeme eingesetzt. Die vorgestellte Arbeit konzentriert sich auf die Entwicklung ganzheitlicher AR-Arbeitsplätze für den Einsatz in kleinen und mittleren Unternehmen (KMU). Das entwickelte AR- Handarbeitskonzept beinhaltet eine Just-in-time-Darstellung der Arbeitsaufgaben auf Werkstücken mit automatisierter Fertigungskontrolle. Als Reaktion auf kurze Produktlebenszyklen und hohe Produktvielfalten sind alle Komponenten auf maximale Flexibilität ausgelegt. Ein Umrüsten auf neue Produkte kann innerhalb von Minuten erfolgen. Y1 - 2020 U6 - https://doi.org/10.17560/atp.v62i10.2495 SN - 2364-3137 VL - 62 IS - 10 PB - Vulkan-Verlag CY - Essen ER - TY - JOUR A1 - Wollert, Jörg A1 - Booke, Andreas T1 - IoT von der Stange JF - elektronik N2 - Heute sollte am besten jedes Gerät in die große Rechnerwolke eingebettet werden. Doch so einfach ist das nicht, denn Cloud ist viel mehr als nur das Internet der Dinge. Als Anwender muss man sich also fragen, welche Dienste man möchte und welchem Anbieter man sein Vertrauen schenkt. KW - Einbetten in das Internet der Dinge Y1 - 2016 IS - 21 (2016) SP - 30 EP - 37 PB - WEKA-Fachmedien CY - München ER - TY - JOUR A1 - Pfaff, Raphael A1 - Schmidt, Bernd T1 - Daten in der Cloud - und dann? JF - Deine Bahn N2 - Schienenverkehrssysteme stehen in zunehmendem Wettbewerb, sowohl untereinander als auch mit anderen Verkehrsträgern. Als wichtiger Aspekt zur Steigerung der Kosteneffizienz wird die Digitalisierung des Betriebs und der Fahrzeuge betrachtet. Über eine Prognose der Ausfallwahrscheinlichkeit bzw. Restlebensdauer von Subsystemen können mittels Digitalisierung die Instandhaltungskosten gesenkt werden. Die geringen Fehlerraten im System Bahn machen die Nutzung besonderer Simulationstechniken notwendig. In diesem Beitrag wird gezeigt, wie sich die Subsystemverfügbarkeit aus den beobachteten Fehlerraten der Teilfunktionen vorhersagen lässt. Y1 - 2016 SN - 0948-7263 IS - 6 SP - 50 EP - 55 PB - Bahn-Fachverlag CY - Berlin ER - TY - JOUR A1 - Pfaff, Raphael A1 - Enning, Manfred T1 - Güterwagen 4.0 - Der Güterwagen für das Internet der Dinge. Teil 2: Ausgewählte technische Aspekte und Prozesse JF - ETR - Eisenbahntechnische Rundschau Y1 - 2017 SN - 0013-2845 VL - 66 IS - 5 SP - 74 EP - 77 PB - DVV Media Group CY - Hamburg ER - TY - JOUR A1 - Reisgen, Uwe A1 - Schäfer, Johannes A1 - Wilms, Konrad A1 - Schleser, Markus T1 - Aufmischungsarmes, dickschichtiges MSG-Auftragschweißen mit entkoppelter Zweidrahttechnik JF - Schweißen und Schneiden N2 - Für Auftragschweißaufgaben existiert eine Vielzahl an verfahrenstechnischen Prozessvarianten, die je nach Charakteristik und Anwendungsfall ausgewählt werden. Ein Nachteil der vorwiegend verwendeten Metall- Schutzgasschweißprozesse (MSG) für das Auftragschweißen ist durch die direkte Kopplung von Drahtvorschub zu Energieeintrag gegeben. Die vorgestellte Zweidraht-Prozessvariante kann durch die Ausbildung eines übertragenen und eines nicht-übertragenen Lichtbogens die elektrische Leistung beider Lichtbögen variieren und damit einen direkten Einfluss auf die Prozessgrößen Abschmelzleistung und Aufschmelzgrad nehmen. Im Speziellen besteht über die Entkopplung von Drahtvorschub zu Schweißstromstärke die Möglichkeit eines niederenergetischen Betriebs trotz hoher Drahtvorschubgeschwindigkeit. Damit lassen sich Aufschmelzgrade unter 2% umsetzen und Abschmelzleistungen bis zu 15 kg/h realisieren. Y1 - 2017 SN - 0036-7184 VL - 69 IS - 12 SP - 838 EP - 843 PB - DVS Verlag CY - Düsseldorf ER - TY - JOUR A1 - Pfaff, Raphael A1 - Enning, Manfred T1 - Die nachhaltige Alternative zum autonomen Lastwagen JF - Deine Bahn Y1 - 2017 IS - 10 SP - 22 EP - 26 ER -