The Wrocław engineers’ work is part of the Laser metal wire deposition in the absence of gravity (Lamda-g) project, carried out under a European Space Agency competition, Michał Ciepielski from the university’s press office reports.

Paweł Widomski, PhD, head of the Wrocław team from the Department of Metal Forming, Welding and Metrology, said the project adapts an existing 3D metal printing method, laser metal wire deposition, for use in weightless conditions.

‘For many years, metal 3D printing was primarily associated with powder-based technologies, which, while precise, have significant limitations. Metal powder is expensive and its use requires tightly sealed chambers, significantly limiting the size of the designed components,’ Widomski said. He added that using metal powders in weightlessness poses further technical challenges.

Using solid wire instead of powder increases efficiency, allowing several times greater material deposition over the same period, according to Widomski. The Wrocław team uses laser technology with coaxial heads employing multiple low-power lasers to ensure stability when building successive layers, especially in the absence of gravity.

‘Without gravity, the deposition process changes because the droplet can +escape+ if the viscosity is insufficient. The material’s cooling and crystallization processes will be different, which can lead to stresses, cracks, or defects in the metal structure. Therefore, we must predict how the liquid metal will behave to avoid situations where the energy is too low to melt the wire, or too high, leading to its spilling and product deformation,’ Widomski explained.

Miniaturizing the printer is also a challenge. ‘On space stations like the ISS, the power available is limited. This is why the entire device must operate at a power of around 1 kilowatt, which is comparable to the power consumption of a small electric kettle. The operation of the metal-melting laser, cooling systems, control computers, and positioning mechanisms must all be within this limit,’ Widomski said.

The printer is intended for tasks such as producing spare parts in orbit, improving the operation and maintenance of space stations.

The Lamda-g consortium includes the University of Manchester (UK, project leader), Cranfield University (UK), University of Dublin (Ireland), the Institute of Materials Physics in Space in Cologne (Germany), and Wrocław University of Science and Technology. Wrocław scientists are responsible for developing the printing system, analysing print microstructure and properties, and selecting parameters to ensure quality and safety in space.

The device will be tested during parabolic flights aboard Maxus suborbital rockets, which are used for microgravity research. The Lamda-g project is scheduled for completion in 2029. (PAP)

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