Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    Embedding electronics into additive manufactured components using laser metal deposition and selective laser melting
    ( 2018)
    Petrat, Torsten
    ;
    Kersting, Robert
    ;
    Graf, Benjamin
    ;
    Rethmeier, Michael
    The paper deals with the integration of a light emitting diode (LED) into an additive manufactured metal component. Selective laser melting (SLM) and laser metal deposition (LMD) are used. The material used is the chrome-nickel steel 316L. The basic component is manufactured by means of SLM and consists of a solid body and an area with grid structure. The solid body includes a duct in the shape of a groove with a recess for the positioning of the power cable. The LED is embedded in the grid structure via an inlet from the solid body. In further processing, the groove is filled with LMD. Two strategies with different parameter combinations were investigated. It shows that a high energy input near the power cable leads to its destruction. By using multiple parameter combinations during the manufacturing process, this destruction can be prevented. There was a comparison of both strategies with regard to the necessary number of tracks and duration of welding time.
  • Publication
    Assessing the predictive capability of numerical additive manufacturing simulations via in-situ distortion measurements on a LMD component during build-up
    ( 2018)
    Biegler, Max
    ;
    Graf, Benjamin
    ;
    Rethmeier, Michael
    Due to rapid, localized heating and cooling, distortions accumulate in additive manufactured laser metal deposition (LMD) components, leading to a loss of dimensional accuracy or even cracking. Numerical welding simulations allow the prediction of these deviations and their optimization before conducting experiments. To assess the viability of the simulation tool for the use in a predictive manner, comprehensive validations with experimental results on the newly-built part need to be conducted. In this contribution, a predictive, mechanical simulation of a thin-walled, curved LMD geometry is shown for a 30-layer sample of 1.4404 stainless steel. The part distortions are determined experimentally via an in-situ digital image correlation measurement using the GOM Aramis system and compared with the simulation results. With this benchmark, the performance of a numerical welding simulation in additive manufacturing is discussed in terms of result accuracy and usability.
  • Publication
    Laser-plasma-cladding as a hybrid metal deposition-technology applying a SLM-produced copper plasma nozzle
    ( 2018)
    Brunner-Schwer, Christian
    ;
    Kersting, Robert
    ;
    Graf, Benjamin
    ;
    Rethmeier, Michael
    Laser-Metal-Deposition (LMD) and Plasma-Transferred-Arc (PTA) are well known technologies which can be used for cladding purposes. The prime objective in combining LMD and PTA as a Hybrid Metal Deposition-Technology (HMD) is to achieve high deposition rates at low thermal impact. Possible applications are coatings for wear protection or repair welding for components made of steel. The two energy sources (laser and plasma arc) build a joint process zone and are configurated to constitute a stable process at laser powers between 0.4-1 kW (defocused) and plasma currents between 75-200 A. Stainless steel 316L serves as filler material. For this HMD process, a plasma Cu-nozzle is designed and produced by powder bed based Selective Laser Melting. The potential of the HMD technology is investigated and discussed considering existing processes. This paper demonstrates how the interaction of the two energy sources effects the following application-relevant properties: deposition rate, powder efficiency and energy input.
  • Publication
    Laser-Pulver-Auftragschweißen als Reperaturverfahren
    ( 2012)
    Graf, Benjamin
    Der Bedarf an innovativen Reparaturtechnologien steigt zusehends. Insbesondere das Laser-Pulver-Auftragschweißen rückt dabei in den Fokus des Interesses. Mit Hilfe dieses Verfahrens lassen sich Bauteile aus unterschiedlichsten Werkstoffen wiederherstellen: Dazu gehören metallische Standardwerkstoffe wie Edel-, Werkzeug- oder Vergütungsstähle sowie Titan-, Kupfer- oder Nickellegierungen. Selbst Bauteile aus Sphäroguss können damit bearbeitet werden. Im Vergleich zu konventionellen Verfahren bietet Laser-Pulver-Auftragschweißen durch den definierten Wärmeeintrag und den endkonturnahen Materialauftrag qualitative sowie wirtschaftliche Vorteile. Forscher am Fraunhofer IPK qualifizieren die Technologie für die Reparatur von hochpräzisen Bauteilen und temperaturempfindlichen Werkstoffen.
  • Publication