The metal Laser Powder Bed Fusion (PBF-LB/M) process offers numerous advantages, but its widespread industrial adoption is hindered by limited reliability and post-processing costs. To overcome these limitations, we have developed an Eddy Current Testing (ECT) array system that integrates directly into the recoater mechanism of a PBF-LB/M machine. This enables the acquisition of layer-by-layer data during recoater motion, providing immediate feedback after each layer and data that can be used to prepare compliant part certificates.

The ECT data supports quality assessment in four primary areas: detecting material variations, identifying localized near surface discontinuities, recognizing geometric distortions, and characterizing powder bed properties such as uniformity. We present a series of representative cases that demonstrate the detection of deviations across all these domains, which is unique among insitu monitoring methods deployed in PBF-LB machines. An algorithm capable to automatically identify indications related to localized defects will be presented.

One critical yet unpredictable defect that can occur even under stable process conditions is spatter, which can cause localized lack of fusion. We showcase cases where spatter is detected through both high-resolution optical imaging (computer vision) and eddy current sensing. While computer vision algorithms can accurately identify the location and size of spatter particles, only ECT enables a quantitative evaluation of their impact on the part’s structural integrity, even in subsequent layers. Notably, the severity of spatter-induced defects can be directly inferred from the ECT signal, allowing for real-time evaluation of their effects.

In summary, this study demonstrates the potential of recoater-integrated ECT monitoring to detect process anomalies and part defects in real-time.