Optical, layerwise monitoring of powder bed fusion

In powder bed fusion additive manufacturing, pre-placed layers of powder are successively fused to form three-dimensional components. During part build-up, flaws in the material or part geometry can occur and lead to an unacceptable part quality. Common flaws include porosity, poor surface finish, and thermal deformation. Here, a layer-wise imaging technique is presented for process monitoring. The technique relies on collection and analyses of images taken under oblique illuminations of fused and pre-placed powder layers. Results of three-dimensional reconstruction of image data and identification of potential flaws are presented.