Pixel Intensity Of Near-Infrared Long-Exposure Images Acquired In-Situ As A Quality Control Tool In Laser Powder Bed Fusion Of Ni-Base Hastelloy X

Paper in proceeding, 2022

Reliability improvement of laser powder bed fusion relies on implementing in-situ process monitoring and control. One of the monitoring systems that has shown promising advances towards this goal is optical tomography based on long-exposure near-infrared layerwise imaging. The system outputs grayscale images that require adequate processing to flag undesirable deviations. This study aims to assess the viability of analysis of pixel intensity values to identify systematic internal defects. Hastelloy X specimens were manufactured with varying process parameters to generate varying defect types and contents. The outputs of the monitoring system were used for estimating the defect content in the specimens. The results show the suitability of pixel intensity analysis to discriminate processability and occurrence of systematic defects to have limited applicability, which is attributed to the predominant influence of process parameters in the pixel intensity values.