ISS conducts 3D printing experiments on capillary action in microgravity
The experiment originally started at the ISS Research Lab Program at the Valley Christian High School in San José, USA
Since the year 2000, astronauts at the International Space Station (ISS) have used the special conditions of space, such as the presence of permanent microgravity, for experiments that provide revolutionary results.
One of the experiments that is expected to be started on the ISS in 2023 is connected to capillary action in microgravity – an experiment that started at the ISS Research Lab Program at the Valley Christian High School in San José, USA. For the experiment on capillary action in microgravity, the team of students found a service provider to manufacture millimeter-scale lattices. The result of the experiment is expected to give detailed insights into the effect of microgravity on the water-absorbing properties of lattices.
The challenge to find a technology suitable for the production of the lattices – with struts as thin as 0.5mm in diameter – was bigger than expected, as the complex design was not feasible with conventional manufacturing technologies. As is often the case – additive manufacturing was the solution to this challenge.
A second challenge was that the material for the lattices needed to match certain requirements – the parts needed to be resistant to vibrations, low temperatures, and heat. In addition to this, the fact that the design was not printable with conventional metal powder-bed fusion and binder-jetting 3D printing technologies made it necessary to further investigate additive manufacturing opportunities.
The already-established micro (stereolithography) SLA technology was identified as a suitable technology to manufacture the lattices, as it is known for the ability to provide micro parts with thin structures – out of resin.
However, as metal was the preferred material, the students ultimately chose to go with the newer, less established Lithography-based metal manufacturing (LMM) – a sinter-based additive manufacturing technology especially suitable for producing micro metal parts with high precision. The students then reached out to the American 3D printing service provider, Qualified 3D – the exclusive reseller of the German start-up, MetShape GmbH, in the US.
MetShape is the co-developer of the LMM technology and possesses unique know-how in the handling of the technology. The starting material is a combination of metal powder and a photosensitive polymer binder. This so-called feedstock is applied to a building platform and selectively cross-linked from above using mask exposure to UV light – resulting in the green part – which is then debinded and sintered.
The advantages of the technology are in particular the high resolution and precision as well as the noteworthy surface quality. It is especially suitable for filigree metal components and parts that have sharp-edged geometries.
