Browsing by Subject "quality monitoring"
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Item In-Situ Layer-Wise Quality Monitoring for Laser-Based Additive Manufacturing Using Image Series Analysis(University of Texas at Austin, 2019) Esfahani, Mehrnaz Noroozi; Bian, Linkan; Tian, WenmengQuality assurance has been one of the major challenges in laser-based additive manufacturing (AM) processes. This study proposes a novel process modeling methodology for layer-wise in-situ quality monitoring based on image series analysis. An image-based autoregressive (AR) model has been proposed based on the image registration function between consecutively observed thermal images. Image registration is used to extract melt pool location and orientation change between consecutive images, which contains sensing stability information. Subsequently, a Gaussian process model is used to characterize the spatial correlation within the error matrix. Finally, the extracted features from the aforementioned processes are jointly used for layer-wise quality monitoring. A case study of a thin wall fabrication by a Directed Laser Deposition (DLD) process is used to demonstrate the effectiveness of the proposed methodology.Item Online Quality Control of Selective Laser Melting(University of Texas at Austin, 2011-08-17) Craeghs, Tom; Clijsters, Stijn; Yasa, Evren; Kruth, Jean-PierreSelective Laser Melting (SLM) is an Additive Manufacturing technique which allows producing three-dimensional metallic parts from powder material, using a layer-by-layer fashion. Typical applications of this technology are parts with high geometrical complexity or internal features such as biomedical implants or casting molds with conformal cooling channels. In order to break through in industries with very high quality standards (such as aerospace industries), an important issue to be addressed is quality monitoring and control during the actual building process. Online quality control can significantly increase the robustness of the process by enabling to check the quality of the building process in the earliest possible stage, such that eventually corrective actions can be taken during the process. This is in contrast with on-line and a posteriori quality control which does not allow taking corrective measures if the quality of the part does not meet the desired quality standard. The development of a framework for online quality control of Selective Laser Melting is the subject of this paper. The framework consists of two complementary systems: a system for visual inspection of powder deposition and a system for online and real-time monitoring of the melt pool. A combination of these two systems enables to guarantee the quality of SLM parts with high confidence.