Melt pool instability detection using coaxial photodiode system validated by in-situ X-ray imaging

A co-axial photodiode monitoring system with high temporal resolution has been integrated into a proven test bench enabling synchronized side-view high speed X-ray imaging of melt pool dynamics and top-view spectral emission characterization of the melt pool. This setup enables direct observation of melt pool phenomena and correlation between the two monitoring systems which can be directly scaled to commercial systems. The work demonstrates a 92% detection rate in keyhole collapse phenomena related to defect generation in SLM. Furthermore, the impact of gas flow on monitoring signals is studied to understand the fundamental importance of gas flow in commercial systems. & COPY; 2023 CIRP. Published by Elsevier Ltd. All rights reserved.

Automated summary

A co-axial photodiode monitoring system with high temporal resolution has been integrated into a proven test bench, allowing for synchronized side-view high-speed X-ray imaging for observing melt pool dynamics and top-view spectral emission characterization of the melt pool. The correlation between these two monitoring systems can be directly scaled to commercial systems. The study shows a 92% detection rate of keyhole collapse phenomena related to defect generation in selective laser melting (SLM), as well as investigates the impact of gas flow on monitoring signals to understand its fundamental importance in commercial systems.