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Engineering Science in
            Additive Manufacturing                                        ML in MAM monitoring and control through images




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            Figure 5. Schematic diagram of an X-ray imaging system: (A) Laser powder bed fusion.43 Reproduced with permission from Elsevier. Copyright © 2018
            The Authors; (B) direct energy deposition.  Reproduced with permission from Elsevier. Copyright © 2023 The Authors. Both are distributed under a
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            CC-BY 4.0 license (https://creativecommons.org/licenses/by/4.0/).
            and structural changes within the sample. For example,   addition, Ito et al.  developed an acoustic sensing-based
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            Tempelman et al. and Li et al. 63,64  recorded acoustic signals   method to detect microdefects, such as cracks and pores,
            produced during the LPBF process to detect the onset of   at various locations in the LPBF process.
            internal pores. They then successfully extracted feature
            vectors that correlated with internal pore formation.   Acoustic imaging proves to be a valuable tool in
            In the DED process, Chen et al.  recorded raw acoustic   MAM for detecting defects, predicting pore formation,
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            signals and marked regions where defects were identified.   and  enhancing  the  overall  quality  control  of  MAM
            Subsequently,  they  trained  a  CNN  model  to  predict   processes. Its ability to capture real-time acoustic signals
            the occurrence of keyhole pores with 93% accuracy. In   enables researchers to have a better understanding of


            Volume 1 Issue 1 (2025)                         7                              doi: 10.36922/esam.8548
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