Developing and testing a 3D printer for space experiment "3D printing" in the Russian segment of the International Space Station

The use of additive manufacturing in space is one of the developing fields addressing a wide range of tasks on building various structures and products in microgravity environment. In particular, 3D printing technology is required to build products with unique properties onboard space stations and in long-duration missions, including tools and life support elements. This study presents results of testing a 3D printer designed to print articles using polymer thermoplastic materials, adapted to and built for a space experiment onboard the Russian Segment of the International Space Station (ISS). A series of tests was run to determine the 3D printer reliability and performance under these specific operating conditions, as well as its compliance with the requirements for devices delivered to the ISS. The work particularly focused on vibration strength tests of the device under development. A specialized electrodynamic vibration table was used to analyze the natural frequencies of the article before and after exposure to sinusoidal vibration, establishing, as a result, the integrity and stiffness of the structure under test. The recommendations were also provided to increase stiffness and damping of the device at problematic points. As an alternative method of control, the 3D printer moving parts and its body were subjected to laser scanning vibrometry. The data obtained from the laser Doppler scanning vibrometry were compared against the results from the 3D printer vibration tests on the electrodynamic vibration table. The paper demonstrates the advantage of the non-contact vibration measuring technique over the traditional vibration diagnostics method owing to high measuring accuracy, the ability to test hard-to-reach areas on the device, as well as the absence of any effect of the attached mass on the measured vibration data.