UCL researchers use X-rays to analyse spatter during 3D printing

According to University College London (UCL), a common issue with Laser Powder Bed Fusion (LPBF) is the formation of spatter, which is created from tiny particles that can cause surface defects and porosity in the printed parts. These defects can weaken the components, making them unsuitable for critical applications in industries like aerospace and energy. Additionally, spatter particles can oxidize, reducing the recyclability of the unused powder.

A team of researchers from UCL Mechanical Engineering, led by Prof. Lee and Dr. Leung, has made significant progress in understanding how spatter is formed and how it behaves during the LPBF process. They used a custom-built LPBF machine, called the Quad-laser in situ and operando process replicator (Quad-ISOPR), which is equipped with four lasers and an industrial scan head system from Renishaw Plc. The machine also has a special chamber filled with argon gas to create the ideal environment for printing.

By combining this machine with high-speed X-ray imaging at the European Synchrotron Radiation Facility (ESRF), the team was able to capture detailed images of the spatter and the molten metal pool during printing. These images were taken at an incredibly fast rate of 40,000 frames per second, allowing the researchers to see the spatter dynamics in great detail.

The team’s observations led to the discovery of two new mechanisms that cause spatter and defects. This new understanding has helped them propose strategies to reduce defects and improve the surface quality of the printed parts. The insights gained from this research could lead to better LPBF processes, which would be a significant advancement for manufacturing critical components in the aerospace and energy sectors.

The team’s publication can be read here.