Sigma Labs Inc (SASI)

[jpi]

https://www.sciencedirect.com/science/article/pii/S0925527318300926
The PrintRite3D® technology (Sigma Labs Inc., Santa Fe, New Mexico, USA) gives an example of the current industrial standard. Optical monitoring detects deviations of the geometry of the build from a reference ‘gold standard’ image, up to a resolution of 100?µm in-plane (Sigma Labs, 2017). Changes in the temperature of the melt pool are detected from a change in the emissivity. Advances in research have explored alternative imaging techniques including optical coherence tomography for surface characterisation (Guan et al., 2016) and low-coherence interferometric imaging for melt pool morphology (Kanko et al., 2016). Zhao et al. (2017) present in situ monitoring of the physical processes during powder bed fusion using high-speed x-ray imaging. The long-term requirements of industry and aims of research are to create a closed-loop system (Spears and Gold, 2016), where the process parameters are controlled by the feedback, thus allowing for in-build compensation of fluctuations as they occur.