Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    Application of D-optimum experimental designs in consideration of restrictions for laser metal deposition
    ( 2017)
    Marko, Angelina
    ;
    Graf, Benjamin
    ;
    Gook, Sergej
    ;
    Rethmeier, Michael
    The process of laser metal deposition can be applied in many ways. Mostly, it is relevant to coating, for repair welding and for additive manufacturing. To increase the effectiveness and the productiveness, a good process understanding is necessary. Statistical test planning is effectual and often used for this purpose. For financial and temporal reasons, a restriction of the test space is reasonable. In this case, it is recommended to use a D-optimal experimental design which is practically applied to extend existing test plans or if process limits are known. This paper investigates the applicability of a D-optimum experimental design for the laser metal deposition. The results are compared to the current results of a full factorial test plan. Known restrictions are used for the limitation of the test space. Ti6Al4 is utilized as substrate material and powder. Comparable results of the D-optimal experimental design and of the full factorial test plan can be demonstrated. However, 80 % of time can be saved by the experimental procedure. For this reason, the application of D-optimal experimental design for laser metal deposition is recommend.
  • Publication
    Design of experiments for laser metal deposition in maintenance, repair and overhaul applications
    ( 2013)
    Graf, Benjamin
    ;
    Ammer, Stefan
    ;
    Gumenyuk, Andrey
    ;
    Rethmeier, Michael
    Modern and expensive parts lead to an increasing demand for maintenance, repair and overhaul (MRO) technologies. Instead of part replacement, MRO technologies are economically advantageous throughout the life cycle. Laser metal deposition as modern MRO technology can be used to repair cracks or protect damaged surfaces with a hard facing layer. It is necessary to adjust weld bead profile to the specific task. For this purpose, Design of Experiment (DoE) has a high potential to decrease experimental effort. In this paper, a full factorial design is used to determine the effect of process parameters on the geometric dimensions of the weld bead. The paper is of interest to engineers working with laser metal deposition as well as DoE methods.
  • Publication
    Laser metal deposition as repair technology for stainless steel and titanium alloys for petrochemicals industry
    ( 2012)
    Graf, Benjamin
    ;
    Gumenyuk, Andrey
    ;
    Rethmeier, Michael
    In a repair process chain for petrochemicals industry, damaged areas or cracks can be removed by milling and subsequently be reconditioned with new material deposition. The use of laser metal deposition has been investigated for this purpose. The material has been deposited into different groove shapes, using both stainless steel and Ti-6Al-4V which are widely used in petrochemicals industry. The influence of welding parameters on the microstructure and the heat affected zone has been studied. The parameters have been modified in order to achieve low heat input and consequently low distortion as well as low metallurgical impact. Finally, an evaluation of the opportunities for an automatized repair process is made with the aim of future application in petrochemicals industry.
  • Publication
    Laser metal deposition as repair technology for stainless steel and titanium alloys
    ( 2012)
    Graf, Benjamin
    ;
    Gumenyuk, Andrey
    ;
    Rethmeier, Michael
    In a repair process chain, damaged areas or cracks can be removed by milling and subsequently be reconditioned with new material deposition. The use of laser metal deposition has been investigated for this purpose. The material has been deposited into different groove shapes, using both stainless steel and Ti-6Al-4 V. The influence of welding parameters on the microstructure and the heat affected zone has been studied. The parameters have been modified in order to achieve low heat input and consequently low distortion as well as low metallurgical impact. Finally, an evaluation of the opportunities for an automatized repair process is made.