Development of Eddy Current Imaging for Defect Identification and Metrology in Manufacturing Applications

Eddy current testing is a non-destructive evaluation (NDE) method for identifying flaws in conductive media. Traditionally, it has seen use in bulk characterization applications in the petroleum, aerospace, and biomedical industries. Eddy current imaging possesses advantages such as quick acquisition times, low cost, and no ionizing radiation in comparison to conventional methods like X-Ray inspection. These traits make it a good candidate for in-situ imaging applications across manufacturing methods. The proposed work aims to enable a novel and efficient imaging mode for conductive materials with three main objectives: (1) Build an Eddy current tomography apparatus while determining bounds of sensitivity to sample geometry, frequency of magnetic oscillation, and material. (2) Develop a non-linear back-projection algorithm for use with globally and locally, converging fields. This algorithm shall be applied to the reconstruction schema for three-dimensional Eddy current tomographic imaging. (3) Apply the outcomes of the previous objectives to a multi-material sample to spatially map volumes of distinct phases or materials. These objectives when combined will allow for creating quantifiable performance metrics of this imaging mode. The prototype resulting from this work will be used to inform further work towards advancements in Eddy current tomographic imaging for in situ manufacturing processes.