Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    Adaptive Reparatur-Prozesskette
    ( 2023-02-11)
    Müller, Vinzenz
    ;
    Mönchinger, Stephan
    ;
    Colombo, Giovanna Fiocco
    ;
    Biegler, Max
    ;
    Rethmeier, Michael
    Das additive Fertigungsverfahren Laser-Powder Directed Energy Depositon (LP-DED), kombiniert mit automatisierten Reverse-Engineering-Ansätzen, bietet die Möglichkeit, Bauteile effizient zu reparieren. Durch intelligente Algorithmen können im sogenannten Scangineering 3D-Scandaten von Bauteilen vorverarbeitet, ausgerichtet und parametrisiert werden. Die erkannten geometrischen Defekte werden zur Errechnung der Werkzeugwege für den additiven Aufbau verwendet und mittels des LP-DED-Prozesses aufgeschweißt und repariert. Dabei kommen vor allem die Vorteile der flexiblen Prozessführung, ein hoher Automatisierungsgrad und gute Reproduzierbarkeit zum Tragen.
  • Publication
    Mittels Scangineering und Schweiß-Knowhow zum reparierten Umformwerkzeug
    ( 2022-12-19)
    Biegler, Max
    ;
    Mönchinger, Stephan
    ;
    Müller, Vinzenz
    ;
    Rethmeier, Michael
    Zum wirtschaftlichen und nachhaltigen Einsatz von Stanz- und Formwerkzeugen ist in der Regel eine Reparatur der verschlissenen Werkzeuge erforderlich. Das Additive Fertigungsverfahren Laser-Powder Directed Energy Depositon (LP-DED) in Kombinationen mit intelligenten Reverse-Engineering-Ansätzen bietet die Möglichkeit, Bauteile materialschonend und effizient zu reparieren.
  • Publication
    Transferability of ANN-generated parameter sets from welding tracks to 3D-geometries in Directed Energy Deposition
    ( 2022-11-04)
    Marko, Angelina
    ;
    Bähring, Stefan
    ;
    Raute, Maximilian Julius
    ;
    Biegler, Max
    ;
    Rethmeier, Michael
    Directed energy deposition (DED) has been in industrial use as a coating process for many years. Modern applications include the repair of existing components and additive manufacturing. The main advantages of DED are high deposition rates and low energy input. However, the process is influenced by a variety of parameters affecting the component quality. Artificial neural networks (ANNs) offer the possibility of mapping complex processes such as DED. They can serve as a tool for predicting optimal process parameters and quality characteristics. Previous research only refers to weld beads: a transferability to additively manufactured three-dimensional components has not been investigated. In the context of this work, an ANN is generated based on 86 weld beads. Quality categories (poor, medium, and good) are chosen as target variables to combine several quality features. The applicability of this categorization compared to conventional characteristics is discussed in detail. The ANN predicts the quality category of weld beads with an average accuracy of 81.5%. Two randomly generated parameter sets predicted as “good” by the network are then used to build tracks, coatings, walls, and cubes. It is shown that ANN trained with weld beads are suitable for complex parameter predictions in a limited way.
  • Publication
    Prognose von Qualitätsmerkmalen durch Anwendung von KI-Methoden beim "Directed Energy Deposition"
    ( 2022-10)
    Marko, Angelina
    ;
    Bähring, Stefan
    ;
    Raute, Maximilian Julius
    ;
    Biegler, Max
    ;
    Rethmeier, Michael
    Dieser Beitrag enthält die Ergebnisse eines im Rahmen der DVS Forschung entwickelten Ansatzes zur Qualitätssicherung im Directed Energy Deposition. Es basiert auf der Verarbeitung verschiedener während des Prozesses gesammelter Sensordaten unter Anwendung Künstlicher Neuronale Netze (KNN). So ließen sich die Qualitätsmerkmale Härte und Dichte auf der Datenbasis von 50 additiv gefertigten Probenwürfel mit einer Abweichung < 2 % vorhersagen. Des Weiteren wurde die Übertragbarkeit des KNN auf eine Schaufelgeometrie untersucht. Auch hier ließen sich Härte und Dichte hervorragend prognostizieren (Abweichung < 1,5 %), sodass der Ansatz als validiert betrachtet werden kann.
  • Publication
    Joining 30 mm Thick Shipbuilding Steel Plates EH36 Using a Process Combination of Hybrid Laser Arc Welding and Submerged Arc Welding
    ( 2022-08-04)
    Gook, Sergej
    ;
    Midik, Ahmet
    ;
    Biegler, Max
    ;
    Gumenyuk, Andrey
    ;
    Rethmeier, Michael
    This article presents a cost-effective and reliable method for welding 30 mm thick sheets of shipbuilding steel EH36. The method proposes to perform butt welding in a two-run technique using hybrid laser arc welding (HLAW) and submerged arc welding (SAW). The HLAW is performed as a partial penetration weld with a penetration depth of approximately 25 mm. The SAW is carried out as a second run on the opposite side. With a SAW penetration depth of 8 mm, the weld cross-section is closed with the reliable intersection of both passes. The advantages of the proposed welding method are: no need for forming of the HLAW root; the SAW pass can effectively eliminate pores in the HLAW root; the high stability of the welding process regarding the preparation quality of the weld edges. Plasma cut edges can be welded without lack of fusion defects. The weld quality achieved is confirmed by destructive tests.
  • Publication
    Multiple-Wire Submerged Arc Welding of High-Strength Fine-Grained Steels
    ( 2022)
    Gook, S.
    ;
    El-Sari, Bassel
    ;
    Biegler, Max
    ;
    Rethmeier, Michael
    ;
    Lichtenthäler, F.
    ;
    Stark, M.
    Ensuring the required mechanical-technological properties of welds is a critical issue in the application of multi-wire submerged arc welding process for welding high-strength fine-grained steels. Excessive heat input is one of the main causes for microstructural zones with deteriorated mechanical properties of the welded joint, such as a reduced notched impact strength and a lower structural robustness. A process variant is proposed which reduces the weld volume as well as the heat input by adjusting the welding wire configuration as well as the energetic parameters of the arcs, while retaining the advantages of multi-wire submerged arc welding such as high process stability and production speed.
  • Publication
    Effects on crack formation of additive manufactured Inconel 939 sheets during electron beam welding
    ( 2022)
    Raute, Julius
    ;
    Jokisch, Torsten
    ;
    Biegler, Max
    ;
    Rethmeier, Michael
    The potential of additive manufacturing for processing precipitation hardened nickel-base superalloys, such as Inconel 939 is considerable, but in order to fully exploit this potential, fusion welding capabilities for additive parts need to be explored. Currently, it is uncertain how the different properties from the additive manufacturing process will affect the weldability of materials susceptible to hot cracking. Therefore, this work investigates the possibility of joining additively manufactured nickel-based superalloys using electron beam welding. In particular, the influence of process parameters on crack formation is investigated. In addition, hardness measurements are performed on cross-sections of the welds. It is shown that cracks at the seam head are enhanced by welding speed and energy per unit length and correlate with the hardness of the weld metal. Cracking parallel to the weld area shows no clear dependence on the process variables that have been investigated, but is related to the hardness of the heat-affected zone.
  • Publication
    Багатодротове дугове зварювання високоміцних дрібнозернистих сталей під флюсом
    ( 2022)
    Gook, Sergej
    ;
    El-Sari, Bassel
    ;
    Biegler, Max
    ;
    Rethmeier, Michael
    ;
    Lichtenthäler, F.
    ;
    Stark, M.
    Ensuring the required mechanical-technological properties of welds is a critical issue in the application of multi-wire submerged arc welding process for welding high-strength fine-grained steels. Excessive heat input is one of the main causes for microstructural zones with deteriorated mechanical properties of the welded joint, such as a reduced notched impact strength and a lower structural robustness. A process variant is proposed which reduces the weld volume as well as the heat input by adjusting the welding wire configuration as well as the energetic parameters of the arcs, while retaining the advantages of multi-wire submerged arc welding such as high process stability and production speed
  • Publication
    The Influence of Electrode Indentation Rate on LME Formation during RSW
    ( 2022)
    Böhne, Christoph
    ;
    Meschut, Gerson
    ;
    Biegler, Max
    ;
    Rethmeier, Michael
    During resistance spot welding of zinc-coated advanced high-strength steels (AHSSs) for automotive production, liquid metal embrittlement (LME) cracking may occur in the event of a combination of various unfavorable influences. In this study, the interactions of different welding current levels and weld times on the tendency for LME cracking in third-generation AHSSs were investigated. LME manifested itself as highpenetration cracks around the circumference of the spot welds for welding currents closely below the expulsion limit. At the same time, the observed tendency for LME cracking showed no direct correlation with the overall heat input of the investigated welding processes. To identify a reliable indicator of the tendency for LME cracking, the local strain rate at the origin of the observed cracks was analyzed over the course of the welding process via finite element simulation. While the local strain rate showed a good correlation with the process-specific LME cracking tendency, it was difficult to interpret due to its discontinuous course. Therefore, based on the experimental measurement of electrode displacement during welding, electrode indentation velocity was proposed as a descriptive indicator for quantifying cracking tendency.
  • Publication
    Verbesserung der Vorhersagegüte von künstlichen neuronalen Netzen zum Widerstandspunktschweißen durch Auswertung des dynamischen Widerstands
    ( 2021)
    El-Sari, Bassel
    ;
    Biegler, Max
    ;
    Rethmeier, Michael
    Das Widerstandspunktschweißen ist ein etabliertes Fügeverfahren in der Automobilindustrie. Es wird vor allem bei der Herstellung sicherheitsrelevanter Bauteile, zum Beispiel der Karosserie, eingesetzt. Daher ist eine kontinuierliche Prozessüberwachung unerlässlich, um die hohen Qualitätsanforderungen zu erfüllen. Künstliche neuronale Netzalgorithmen können zur Auswertung der Prozessparameter und -signale eingesetzt werden, um die individuelle Schweißpunktqualität zu gewährleisten. Die Vorhersagegenauigkeit solcher Algorithmen hängt von dem zur Verfügung gestellten Trainingsdatensatz ab. In diesem Beitrag wird untersucht, inwieweit die Vorhersagegüte eines künstlichen neuronalen Netzes durch Auswertung einer Prozessgröße, dem dynamischen Widerstand, verbessert werden kann.