Researchers from UK-based UCL Mechanical Engineering, led by Prof. Lee and Dr. Leung, have made significant strides in understanding how spatter forms and behaves during the Laser Powder Bed Fusion (LPBF) process.

“This new understanding has helped us propose strategies to reduce defects and improve the surface quality of the printed parts,” the team explained. These insights could advance LPBF processes, supporting the production of critical components for aerospace, energy, and other high-performance industries.

LPBF: Powerful Technology with Persistent Challenges

While LPBF is a leading metal 3D printing technology capable of producing intricate, high-quality components, it faces a recurring problem: spatter. Tiny particles created during printing 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,” the researchers note. Additionally, spatter particles can oxidize, reducing the recyclability of unused powder and complicating production efficiency.

X-ray Breakthroughs: Watching Spatter in Real Time

To investigate spatter dynamics in detail, the team used a custom-built Quad-laser in situ and operando process replicator (Quad-ISOPR), featuring four lasers and an industrial scan head system from Renishaw Plc. The machine operates within an argon-filled chamber to maintain optimal printing conditions. A substrate measuring 1 mm through-thickness and 15 mm in height was mounted in the chamber, and a thin layer of powder was automatically deposited on its surface.

By combining this setup with in situ high-speed synchrotron X-ray imaging, the researchers captured both spatter and melt pool behavior during LPBF with exceptional spatial and temporal resolution. The experiments were carried out at the European Synchrotron Radiation Facility (ESRF) on the high-speed imaging beamline ID19, using a polychromatic hard X-ray beam with a mean energy of approximately 30 keV and a camera operating at 40,000 frames per second.

Through high-speed synchrotron X-ray imaging, the spatter dynamic during LPBF was captured and quantified under various processing conditions. Image via UCL.

“Our work predicts the number of spatters formed during LPBF of an Al-Zr-Fe alloy system,” said first author Da Guo, a postdoctoral researcher at UCL. “This prediction can be used for future model validation and minimizing spatter.”

The team continues to study spatter formation across a variety of commercial materials used in 3D printing, aiming to improve surface quality and consistency in LPBF parts for real-world applications.These insights are expected to support the broader adoption of LPBF technology, particularly in industries where component integrity is critical.

Advances in LPBF

The UCL Mechanical Engineering research is part of a growing wave of innovation in laser powder bed fusion. 

In September, At ETH Zurich, a team of students developed a high-speed, multi-material metal 3D printer: a laser powder bed fusion system that rotates both the powder deposition and gas flow nozzles during printing. This allows the machine to process multiple metals simultaneously, without downtime, potentially transforming metal additive manufacturing by cutting production time and costs. 

The new 3D printer allows two different materials to be simultaneously fused by a laser on the rotating platform. Photo via ETH Zurich.

Elsewhere, ADDiTEC, a US-based developer of advanced metal additive manufacturing technologies, unveiled its first Laser Powder Bed Fusion system during RAPID + TCT 2025 in Detroit. The new platform, called Fusion S, expands the company’s technology offerings, which previously focused on Directed Energy Deposition (DED) and Liquid Metal Jetting (LMJ). With this release, ADDiTEC becomes one of the few companies globally offering three complementary metal additive manufacturing technologies.

Similarly, Irish medical device manufacturer Croom Medical introduced TALOS, an LPBF platform for 3D printing tantalum (Ta). The company describes TALOS as a breakthrough for medical implants and industrial applications, highlighting the expanding capabilities and versatility of LPBF technology across sectors.