TY - JOUR A1 - Merz, Benjamin A1 - Schmidt, Jonathan A1 - Poka, Konstantin A1 - Mohr, Gunther A1 - Polte, Julian A1 - Hilgenberg, Kai T1 - Impact of illumination technique on the detectability of irregularities in high-resolution images of visual in-situ process monitoring in Laser Powder Bed Fusion N2 - The layerwise geometry build-up of additive manufacturing (AM) enables the possibility of in-situ process monitoring. The objective is the detection of irregularities during the build cycle, ensuring component quality and process stability. Focus of this work is the visual in-situ monitoring of the process of powder bed fusion with laser beam of metals (PBF-LB/M). Current state of the art visual monitoring systems for PBF-LB/M are limited by low resolution, allowing the detection of gross flaws. In this work a 65 Mpixel high-resolution monochrome camera is integrated into a commercial PBF-LB/M machine enabling a spatial resolution of approx. 17.2 µm/Pixel. The observed inhomogeneities are clustered into directly detectable irregularities, and indirectly detectable irregularities that can be inferred from the surface. In parallel, two different illumination techniques are realized in the process chamber and compared. The impact of the distinct illumination technique, direct light and dark field, on the identification of irregularities is evaluated. KW - Powder bed fusion with laser beam of metals KW - In-situ monitoring KW - High-resolution camera KW - Illumination technique PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610929 DO - https://doi.org/10.1016/j.procir.2024.08.079 SN - 2212-8271 VL - 124 SP - 98 EP - 103 PB - Elsevier B.V. AN - OPUS4-61092 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Merz, Benjamin A1 - Poka, Konstantin A1 - Nilsson, R. A1 - Mohr, Gunther A1 - Hilgenberg, Kai T1 - On the challenges of hybrid repair of gas turbine blades using laser powder bed fusion N2 - Additive manufacturing (AM) processes such as laser powder bed fusion (PBF-LB/M) are rapidly gaining popularity in repair applications. Gas turbine components benefit from the hybrid repair process as only damaged areas are removed using conventional machining and rebuilt using an AM process. However, hybrid repair is associated with several challenges such as component fixation and precise geometry detection. This article introduces a novel fixturing system, including a sealing concept to prevent powder sag during the repair process. Furthermore, a high-resolution camera within an industrial PBF-LB/M machine is installed and used for object detection and laser recognition. Herein, process related inaccuracies such as PBF-LB/M laser drift is considered by detection of reference objects. This development is demonstrated by the repair of a representative gas turbine blade. The final offset between AM build-up and component is analysed. An approximate accuracy of 160 μm is achieved with the current setup. T2 - LiM 2023 CY - Munich, Germany DA - 26.06.2023 KW - Laser powder bed fusion KW - Additive manufacturing KW - Hybrid repair KW - Position detection KW - High-resolution camera PY - 2023 SP - 1 EP - 9 AN - OPUS4-57836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Merz, Benjamin T1 - On the challenges of hybrid repair of gas turbine blades using laser powder bed fusion N2 - Additive manufacturing (AM) processes such as laser powder bed fusion (PBF-LB/M) are rapidly gaining popularity in repair applications. Gas turbine components benefit from the hybrid repair process as only damaged areas are removed using conventional machining and rebuilt using an AM process. However, hybrid repair is associated with several challenges such as component fixation and precise geometry detection. This article introduces a novel fixturing system, including a sealing concept to prevent powder sag during the repair process. Furthermore, a high-resolution camera within an industrial PBF-LB/M machine is installed and used for object detection and laser recognition. Herein, process related inaccuracies such as PBF-LB/M laser drift is considered by detection of reference objects. This development is demonstrated by the repair of a representative gas turbine blade. The final offset between AM build-up and component is analysed. An approximate accuracy of 160 μm is achieved with the current setup. T2 - LiM 2023 CY - Munich, Germany DA - 26.06.2023 KW - Laser powder bed fusion KW - Additive manufacturing KW - Hybrid repair KW - Position detection KW - High-resolution camera PY - 2023 AN - OPUS4-57837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Merz, Benjamin T1 - Impact of illumination technique on the detectability of irregularities for in-situ process monitoring in PBF-LB/M N2 - The layerwise geometry build-up of additive manufacturing (AM) enables the possibility of in-situ process monitoring. The objective is the detection of irregularities during the build cycle, ensuring component quality and process stability. Focus of this work is the visual in-situ monitoring of the process of powder bed fusion with laser beam of metals (PBF-LB/M). Current state of the art visual monitoring systems for PBF-LB/M are limited by low resolution, allowing the detection of gross flaws. In this work a 65 Mpixel high-resolution monochrome camera is integrated into a commercial PBF-LB/M machine enabling a spatial resolution of approx. 17.2 µm/Pixel. The observed inhomogeneities are clustered into directly detectable irregularities, and indirectly detectable irregularities that can be inferred from the surface. In parallel, two different illumination techniques are realized in the process chamber and compared. The impact of the distinct illumination technique, direct light and dark field, on the identification of irregularities is evaluated. T2 - 13th CIRP Conference on Photonic Technologies [LANE 2024] CY - Fürth, Germany DA - 15.09.2024 KW - Powder bed fusion with laser beam of metals KW - In-situ monitoring KW - High-resolution camera KW - Illumination technique PY - 2024 AN - OPUS4-61094 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -