A collaborative project is developing a metal 3D printer for the International Space Station (ISS) to produce the first metal parts in space.
The printer will be delivered to the ISS in early 2023.
The technology could enable the manufacturing and repair of a wide variety of tools and parts directly on site using a single input material. Ultimately, it could lead to the designing of more complex printing systems, such as those that produce habitats on the Moon or Mars.
The ‘Metal3D’ project was commissioned by the European Space Agency (ESA) as a technology demonstrator.
Its aims are to characterise the mechanical properties of a material shaped in microgravity.
To carry out this experiment, two batches of test specimens will be produced by two newly developed identical printers: one in space, one on earth – each capable of operating in both environments. The first batch of test specimens will be made in Toulouse, in terrestrial gravity, while the second will be made within the Columbus module of the ISS, in microgravity.
A unique challenge: Printing under microgravity
In the absence of gravity, most current additive manufacturing processes are no longer usable. This is either because they are not compatible with the space environment (the use of fine powder is dangerous on the ISS), or because their implementation is conflicting with microgravity (powder-bed technologies for example). To make manufacturing in microgravity possible, the partners have chosen to use a process that promotes forces induced by surface tension: this is the wire-laser combination (W-DED).
A laser will be used as the energy source and a 316L stainless-steel wire as the raw material. The laser and the wire feeding system are fixed in the machine frame and the printing table is made movable by three linear axes and one rotary axis. The machine is operated under nitrogen to limit the oxidation of the material and to prevent the risks of combustion. As access to nitrogen is limited in the ISS, the machine’s atmosphere is filtered and cooled throughout the manufacturing process to limit nitrogen consumption and recycle as much as possible of the nitrogen already present in the machine.
Working in partnership
The project is being led by ESA – also playing the role of client – and features industrial and academic partners including Airbus Defence and Space, Highftech Engineering, AddUp, and Cranfield University.
Project management is being undertaken by the Airbus Defence and Space teams in Toulouse, who ensure the integration of the various components of the printer, the power supply, and the conformity for the space environment. Cranfield University is overseeing the energy source and material delivery mechanism – the laser and stainless-steel wire. Highftech is manufacturing the machine enclosure and integrating the machine’s fluid management. Finally, AddUp is making the internal structure and mechanisms of the machine, the PLC that controls it, and the interface that allows communication with the ground.
The expedition of the machine to the ISS is scheduled for February next year, but a follow-up to the project is already in motion. AddUp has established a joint project with Airbus Defense and Space to build a machine inspired by ‘Metal3D’, which will enable developments of this technology to continue.
