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Metal-based additive manufacturing for space travel and weightlessness

This project aims to use a 3D printing process while a research rocket is flying in 2020.

Additive manufacturing, also known as 3D printing, offers a wide range of options for manufacturing components from liquid, powder or thread-like starting material. Basically, materials from all classes such as metals, plastics and ceramics, but also composite materials, are available. Technical market maturity is currently being achieved for more and more raw materials.
The advantages of this group of manufacturing processes depend heavily on the process used and the application. All in all, additive manufacturing can be used to manufacture a large number of components or tools from the same starting material very flexibly and quickly, but above all directly at the respective location. As a result, applications in space travel – in earth orbit or beyond, for example on moon or Mars bases or during flights there – will be of great interest in the future.

Such manufacturing processes, even if they are well-tried and ready for the market on Earth, are by no means trivial to adapt to reduced gravity. On the one hand, there are fundamentally different requirements for the hardware of corresponding production machines, on the other hand, there are often more sophisticated materials that are used in space travel.
The subject of our research project is a process called SLS (Selective Laser Sintering), in which the desired component is formed from individual layers of metallic powder using a focused laser beam – layer by layer. The range of possible materials is very wide with this method, even if adjustments to the various machine parameters sometimes require complex series of measurements.

One of the greatest challenges of this process for preparing for less exposure to gravity, up to weightlessness, is the handling of the metal powder and the targeted application of a powder layer of dense packing and uniform thickness, since these parameters dominate the quality and material properties of the finished component. This layer must also remain stable on the print bed until the laser process is complete and the next layer is applied. In order to achieve this goal, a gas flow is excited and the individual particles of the powder are sucked onto the print bed. This method of stabilizing the powder in the pressure range has already been tested in various variations on parabolic flights and shows a high level of reliability.

This parabolic flight is used to test a completely new system based on the tried and tested principle, which is designed as a payload for a research rocket and will be used on a MAPHEUS rocket for the first time in 2020. This newly developed manufacturing unit works fully automated, has an independent energy supply, is robust against the loads occurring during a rocket launch and is light in weight. The manufacturing process can be monitored from the ground using a telemetry connection. The rocket payload and ground station stand side by side in parabolic flight. In addition to testing the hardware for the first time under weightlessness, it is also about optimizing system parameters for different, demanding materials, such as solid metal glasses.