Comparison of visual and hyperspectral monitoring of the melt pool during Laser Metal Deposition

In the field of additive manufacturing the implementation of real time process monitoring is required to enhance the quality and repeatability of the printed parts. Laser metal deposition (LMD) is a technique where the deposition of material is done in a melt pool created by a high-power laser beam. This paper presents the geometrical properties of such melt pool obtained during blown powder LMD. For achieving these results, the visual and hyperspectral information of the melt pool is used. An analytical model of the melt pool boundary is fitted to high-speed visual images recorded during 3D deposition. At the same time the hyperspectral information provides a way to estimate the temperature and emissivity profiles within the melt pool. The proposed paper discusses the correlation of the hyperspectral and visual high-speed camera results.