Dr.-Ing.

Day, Robin

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  • Publication
    Reflectometry-based investigation of temperature fields during dual-beam Laser Metal Deposition
    ( 2021)
    Gipperich, Marius
    ;
    Peters, Christian
    ;
    Riepe, Jan
    ;
    Day, Robin
    ;
    Bergs, Thomas
    Laser Metal Deposition (LMD) is a high deposition rate metal Additive Manufacturing process. Its applications are basically repair, cladding and manufacturing. The two most commonly used LMD processes are powder-based (LMD-p) and wire-based (LMD-w). Despite the fact that wire-based LMD is more material efficient, process stability is a major concern. By adding a modulated laser beam to the continuous process beam, a change of the melt pool geometry and increased energy absorption are observed. This relation shows great potential to increase process stability. In this contribution, the positive effect of the dual laser-beam use on LMD-w processes is demonstrated. To understand the cause-effect relation, the workpiece temperature field was investigated by optical backscatter reflectometry ( OBR). The results were then correlated to simultaneously performed IR camera measurements of the workpieces upper surface. By better understanding the thermal phenomena in dual-beam LMD, research can improve process temperature control. This leads to a new perspective for the LMD-w manufacturing process in many industry sectors such as mobility, energy and engineering.
  • Publication
    Tailored melt pool shape by dual laser beam LMD-w process
    ( 2020)
    Gipperich, Marius
    ;
    Riepe, Jan
    ;
    Day, Robin
    ;
    Bergs, Thomas
    Additive Manufacturing (AM) is a fast growing manufacturing market. Laser Metal Deposition (LMD) is a high deposition rate metal AM process mostly used for repair, cladding or manufacturing applications. The two commonly used LMD-processes are powder-based (LMD-p) and wire-based (LMD-w). While LMD-p offers high deposition rates up to 2 kg/h (compared to LMD-w with 1kg/h) the handling of powder in terms of health and safety as well as machine wear become important. Furthermore, the material efficiency (due to overspray) is lower compared to the LMD-w AM-process. This is where LMD-w offers advantages, but advanced concepts to improve the stability of the LMD-w process to the level of LMD-p are needed. In this presentation, an approach is investigated to stabilize the LMD-w process by combining continuous wave (cw) laser and low-power pulsed wave (pw) laser. Calorimeter-like absorption measurements as well as deposition experiments are carried out to understand the physical background of the dual laser process and how this setup helps to stabilize the process. Promising results were achieved showing the possibility to tailor the melt pool height and width by a factor of 1.5-2 and an increase of energy absorption by 20%. This leads to a new perspective for the LMD-w manufacturing process (3D part build up, cladding and repair) in many industry sectors such as mobility, energy and engineering.
  • Publication
    Tailored melt pool shape and temperature distribution by a dual laser beam LMD-w process
    ( 2020)
    Gipperich, Marius
    ;
    Riepe, Jan
    ;
    Day, Robin
    ;
    Bergs, Thomas
    Laser Metal Deposition (LMD) is a high deposition rate metal AM process used for repair, cladding or manufacturing. While wire-based LMD (LMD-w) offers several advantages such as high material efficiency and a safe and simple handling of the wire feedstock, advanced concepts are needed to increase the LMD-w process stability. In this presentation, an approach is investigated to stabilize the LMD-w process by combining a continuous wave (cw) laser and a low-power pulsed wave (pw) laser. Calorimeter-like absorption measurements as well as deposition experiments are carried out to understand the physical background of the dual laser process and how this setup helps to stabilize the process. Promising results were achieved showing the possibility to tailor the melt pool height and width by a factor of 1.5-2 and an increase of energy absorption by 20 %. This offers new perspectives for the LMD-w manufacturing process in many industry sectors.