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Felix Wirth, M.Sc.

Akad. Mitarbeiter
Bereich: Maschinen, Anlagen und Prozessautomatisierung
Sprechstunden: nach Vereinbarung
Raum: 012, Geb. 50.36
Tel.: +49 1523 9502630
Felix WirthZab2∂kit edu

76131 Karlsruhe
Kaiserstraße 12


Felix Wirth, M.Sc.

Forschungs- und Arbeitsgebiete:

  • Elektromaschinenbau
  • Hairpin-Technologie

 

Allgemeine Aufgaben:

 

Projekte:

 

Versuchsstände:

 

Lebenslauf:

seit 11/2017 Wissenschaftlicher Mitarbeiter am Institut für Produktionstechnik (wbk) des Karlsruher Instituts für Technologie (KIT)
04/2017 - 08/2017 Auslandsaufenthalt am amtc der Tongji Universität, Shanghai
10/2012 - 10/2017 Studium des Maschinenbaus am Karlsruher Institut für Technologie (KIT)

 

Veröffentlichungen

[ 1 ] Hofmann, J.; Sell-Le Blanc, F.; Krause, M.; Wirth, F. & Fleischer, J. (2016), „Simulation of the Assembly Process of the Insert Technique for Distributed Windings“. Proceedings of 6th International Electric Drives Production Conference (E|DPC), Hrsg. IEEE, S. 144-148.
Abstract:
As the efficiency of electric power trains in hybrid electric vehicles should be increased and at the same time the manufacturing costs reduced, different motor designs and production concepts need to be considered. Because of the nearly sinusoidal magnetic field inside, the stator design with distributed windings, which is typically produced with the insert technique, is technically preferred. The insert technique offers a high productivity because the complete winding assembling process can be done in one step. This results in the fact, that nearly 80% of all electric motors worldwide have distributed windings. In order to enhance the possibilities for distributed windings with the insert technique, the current fill factor needs to be improved. Due to the fact that the actual wire placement cannot be measured und thus not optimized, a simulative approach with a multi-body simulation is used to understand the process interactions between the wires, the stator groove and the tool. This approach will be presented in this paper.

[ 2 ] Wirth, F.; Kirgör, T.; Hofmann, J. & Fleischer, J. (2018), „FE-Based Simulation of Hairpin Shaping Processes for Traction Drives“. 2018 8th International Electric Drives Production Conference (EDPC), Hrsg. IEEE, S. 1-5.
Abstract:
Based on the present change in mobility, there are novel requirements on production technologies of electric drives regarding process reliability, ability for automation, productivity as well as mechanical and electric filling factors. Providing significant advantages compared to conventional winding technologies, the hairpin technology combined with the usage of flat copper wire is a promising opportunity to fulfill the upcoming standards. Hence, the AnStaHa project aims the qualification of the hairpin technology for application in mass production. In spite of numerous advantages, the application of the hairpin technology also shows weaknesses. In particular, the shaping of hairpins is considerably more complex than corresponding process sequences of other winding technologies. The main reasons for this are the rectangular cross section and resulting directional properties of flat copper wires, significant springback effects as well as process-related damage of the wire insulation. Therefore, basic knowledge about the deformation behavior of the wire is required for process dimensioning within the context of system design. This paper handles the numerical simulation of hairpin shaping using the commercial finite element software suite Abaqus FEA. The FE-based approach is validated by experiments for different geometries and includes the complete forming process of hairpins, which is considered to be implemented in two following steps - U-bending and 3-D-shaping. Because the numerical analysis takes wire springback into account, the results can be used for a digital evaluation of hairpin shaping processes during the period of system design.

[ 3 ] Wirth, F.; Hausmann, L.; Halwas, M.; Hofmann, J.; Mayer, D.; Wößner, W. & Fleischer, J. (2019), „Optimierte Fertigung elektrischer Traktionsmotoren durch Technologien der Industrie 4.0“. Future Mobility: automatisiert - vernetzt - elektrisch, Hrsg. Technische Akademie Esslingen e.V., S. 1-14.
Abstract:
Striktere Emissionsvorgaben der Europäischen Union sowie die Endlichkeit fossiler Energieträger werden in der kommenden Dekade zu einem steigenden Absatz elektrifizierter Antriebsstränge führen. Damit die wachsende Nachfrage nach leistungsfähigen Traktionsmotoren sowie die hohen Anforderungen bezüglich Stückzahl und Qualität erfüllt werden können, müssen die innovativen aber vielmals noch unreifen Fertigungsprozesse für den industriellen Einsatz befähigt werden. Die Integration neuartiger Technologien der Industrie 4.0 in die Produktionskette stellt einen vielversprechenden Ansatz zur Lösung dieser Probleme dar. Durch eine digitale Prozessabsicherung können Wickelverfahren vor deren hardwareseitiger Erprobung bewertet und optimiert sowie Inbetriebnahmezeiten verkürzt werden. Zudem gestattet der digitale Zwilling sowohl eine prädiktive Prozesssteuerung als auch die isolierte Betrachtung von Einflussgrößen und darauf basierende Ableitung von Regelungsstrategien. Methoden des maschinellen Lernens und intelligente Algorithmen ermöglichen die Bewertung bislang unbekannter, produktseitiger Merkmale, wie den Lagenaufbau von Leitern in den Nuten von Blechpaketen, sowie die Einhaltung enger Qualitätsvorgaben durch angepasste Montagestrategien.

[ 4 ] Wirth, F.; Hofmann, J. & Fleischer, J. (2019), „Einfluss geometrischer Materialtoleranzen auf die werkzeuggebundene Formgebung und Eigenschaften von Hairpin-Steckspulen“, www.umformtechnik.net, S. 1-18.
Abstract:
Toleranzbedingte Schwankungen des Kupferflachdrahtes stellen eine wichtige Einflussgröße bei der Formgebung von Hairpin-Steckspulen für die Fertigung elektrischer Traktionsmotoren dar. Im vorliegenden Beitrag werden die Wechselwirkungen geometrischer Toleranzen mit den charakteristischen Eigenschaften und der Konturgenauigkeit von Hairpin-Steckspulen durch analytische und numerische Methoden am Beispiel einer werkzeuggebunden Formgebung systematisch untersucht.

[ 5 ] Hausmann, L.; Wirth, F.; Franck, C.; Förderer, M.; Karrer, M.; Hofmann, J. & Fleischer, J. (2019), „Ausbildungsfabrik Statorfertigung“, ZWF Zeitschrift für wirtschaftlichen Fabrikbetrieb, Band 10, S. 621-626.
Abstract:
The transformation process towards electric mobility results in new requirements for product development and production technology, which require the appropriate qualification of employees. In order to enable holistic further training, the wbk Institute for Production Engineering at KIT develops high-quality training concepts for the production of stators of electric traction drives by hairpin technology based on vocational pedagogical methods and integrates them into the overall concept of the training factory stator production.

[ 6 ] Hofmann, J.; Halwas, M.; Weinmann, H.; Wößner, W.; Schäfer, J.; Hausmann, L.; Wirth, F.; Storz, T. & Schild, L. (2019), „Transformationshub Elektromobilität in Baden-Württemberg“ in Auf dem Weg zur Elektromobilität – Wettbewerbsfaktor Produktionstechnik , Hrsg. Fleischer, J.; Lanza, G.; Schulze, V. & , ., Shaker, Berlin, S. 1-29. ISBN/ISSN: 978-3-8440-6953-2
Abstract:
Die Automobilindustrie steckt in einem Transformationsprozess un-geahnten Ausmaßes und Ausgangs. Ob durch striktere europäische Abgasgrenzwerte, den Zwang lokaler Emissionsfreiheit oder den Druck des chinesischen Marktes beim Kampf um eine neue Vorherrschaftsrolle - die Gründe deutscher Automobilisten zur Elektrifizierung sind vielschichtig und die Folgen kaum abschätzbar. Die Frage, ob neue Antriebstechnologien in den Markt eingeführt wer-den, stellt sich mittlerweile kein Automobilhersteller mehr, stattdessen verbleibt die Frage nach dem „wie“. Mit der diesjährigen wbk Herbsttagung „Auf dem Weg zur Elektromobilität – Wettbewerbsfaktor Produktionstechnik“ wollen wir die vorhandenen Chancen im Bereich der Produktionstechnik für die Elektromobilität aufzeigen und einen Beitrag dazu leisten, dass diese auch genutzt werden. Hochkarätige Impulsvorträge aus Industrie und Forschung schaffen die Diskussionsbasis für einen Informationsaustausch zur Elektromobilität. Die wbk-Herbsttagung bietet dabei eine Plattform für den Dialog zwischen Politik, Anwendern, Produzenten, Anlagenbauern sowie dem wbk als Forschungspartner vor Ort.

[ 7 ] Halwas, M.; Sell-Le Blanc, F.; Jux, B.; Doppelbauer, M.; Wirth, F.; Hausmann, L.; Hofmann, J. & Fleischer, J. (2019), „Coherences Between Production Technology and Performance of Electric Traction Drives“. 2019 9th International Electric Drives Production Conference (EDPC), Hrsg. IEEE, S. 1-9.
Abstract:
Coherences between production technology and performance of electric traction drives are published or based on experiential knowledge. The content of this paper shall represent an essential basis for intentions of improving future research and development purposes of production technologies for traction drives, but also of electric machine designs in general. The basic ambition of engineering a new manufacturing technology is to improve the performance of a product, taking several boundary conditions into account, like costs or cycle times. It has to be considered that the conflict area of production and performance are connected by physical characteristics, which are determined by the geometric and material compositions of the electric machine in this context. It is evident that the physical characteristics have a direct impact on the performance of electric machines. However, the production technology has a straight and unavoidable influence on the physical characteristic. An example for this is the slot fill factor, which is determined by the winding technology, but influences the performance of the machine significantly. First, known coherences between physical characteristics and performance of electric machines are considered. Therefore, an extensive summary of technical literature and publications at the current state of the art in science applications is used as a starting point. To give the best possible overview, a summary and visualization dependency matrix is created, in which the various elements of physical characteristic and the resulting performance of the electric machine are compared against each other. Next, the main influences of the different manufacturing processes on the characteristics of electric machines are presented, especially focusing on the winding technology. These contents are also transferred into the dependency matrix.

[ 8 ] Wirth, F. & Fleischer, J. (2019), „Influence of Wire Tolerances on Hairpin Shaping Processes“. 2019 9th International Electric Drives Production Conference (EDPC), Hrsg. IEEE, S. 1-8.
Abstract:
Due to the increasing sales of electric vehicles, new production technologies must be developed for meeting the growing demand for high productivity and quality in electric drives manufacturing. In comparison to conventional winding technologies, the hairpin technology provides significant advantages regarding the ability for automation, the productivity as well as the attainable filling factors, but also exhibits technological weaknesses concerning the process reliability. Since the shaping of hairpin coils represents the initial core process of the winding production by hairpin technology, geometric tolerances of the hairpin contour after shaping have a major impact on the downstream manufacturing processes. Especially the insertion of the coils into the stator slots as well as the twisting and contacting of the open coil sides are highly affected by variations in the positioning and orientation of the hairpin legs. Besides the process-based deviations caused by vibrations and tool displacements, the tolerances of hairpin contours are frequently induced by fluctuations of the geometric and material properties of the wire – like the dimensions and radii as well as the Young’s modulus and flow curve. In this paper, a holistic analysis of geometric and material tolerances of flat wires and their effect on the accuracy of hairpin shaping processes is shown. For this purpose, essential material properties of flat winding wires are characterized by means of tensile tests at first and subsequently used as boundary conditions for a numerical sensitivity analysis of a tool-bound hairpin shaping process. The FE-based analyses are carried out in Abaqus FEA using a fully parametrized simulation model that is validated by means of CT measurements. The derived knowledge about interdependencies between fluctuations of wire properties and the reliability of hairpin shaping processes enables the cost-effective definition of wire tolerances in compliance with quality specifications.

[ 9 ] Wirth, F.; Nguyen, C.; Hofmann, J. & Fleischer, J. (2020), „Characterization of Rectangular Copper Wire Forming Properties and Derivation of Control Concepts for the Kinematic Bending of Hairpin Coils“. Procedia Manufacturing, Hrsg. Elsevier Ltd., S. 678-685.
Abstract:
As a result of the continuously growing demand for electric vehicles, innovative production technologies must be developed to fulfill the high automotive requirements for productivity and quality in the manufacturing of electric drives. By providing advantages regarding the degree of automation, the productivity as well as the attainable filling factors in comparison to established round wire winding technologies, the hairpin technology shows a high potential for meeting the requested specifications but also technological weaknesses, especially concerning the process reliability. The referring production process of stators is normally based on the spatial forming of open, hairpin-shaped coils of enameled flat copper wire as well as subsequent joining and contacting processes. Consequently, the hairpin coils represent the elementary components of the process chain and can be either shaped by robust tool-bound or flexible kinematic bending processes that enable the shaping of different contours at moderate tool costs. In this paper, the essential mechanical forming and product properties of flat copper wires with different dimensions and insulation coatings are characterized by means of uniaxial tensile tests as well as metallographic analyses of the material structure, at first. Subsequently, the identified forming properties are correlated to the applied manufacturing processes drawing, rolling as well as continuous extruding and considered as limits of possible material variations. To evaluate the effect of fluctuating wire qualities on the robustness of kinematic hairpin bending processes, the fabrication tolerances are analyzed by finite element simulations, using the example of elementary kinematic bending operations and modeled changes of the material properties. Based on the knowledge of material-based process tolerances, different control concepts for the kinematic bending of hairpin coils are derived and compared based on technical as well as economic aspects.