In-Situ Defect Detection in Laser Powder Bed Fusion by Using Thermography and Optical Tomography—Comparison to Computed Tomography

By G. Mohr, S. Altenburg, A. Ulbricht, P. Heinrich, D. Baum, C. Maierhofer, K. Hilgenberg. 2020

146 citations recorded by the source corpus.

Among additive manufacturing (AM) technologies, the laser powder bed fusion (L-PBF) is one of the most important technologies to produce metallic components. The layer-wise build-up of components and the complex process conditions increase the probability of the occurrence of defects. However, due to the iterative nature of its manufacturing process and in contrast to conventional manufacturing technologies such as casting, L-PBF offers unique opportunities for in-situ monitoring. In this study, two cameras were successfully tested simultaneously as a machine manufacturer independent process monitoring setup: a high-frequency infrared camera and a camera for long time exposure, working in the visible and infrared spectrum and equipped with a near infrared filter. An AISI 316L stainless steel specimen with integrated artificial defects has been monitored during the build. The acquired camera data was compared to data obtained by computed tomography. A promising and easy to use examination method for data analysis was developed and correlations between measured signals and defects were identified. Moreover, sources of possible data misinterpretation were specified. Lastly, attempts for automatic data analysis by data integration are presented.

Subfields: Automotive Engineering, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/b21ce9bda64a3f9ca0259b2a8cd5638f9b627d8b

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Citations in the corpus

In-situ measurement and monitoring methods for metal powder bed fusion: an updated review (2021, unknown): “Mohr et al (2020) also showed that combining synchronous video imaging at high spatial resolution (NIR camera) and high temporal resolution (medium wave IR camera) increased the capability of detecting volumetric defects compared to imaging with a single sensor.”
Mechanical anisotropy of additively manufactured stainless steel 316L: An experimental and numerical study (2021, background): “More details about the powder can be taken from [37,38].”