3D Printing in Zero Gravity Space Reaches New Milestone

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Researchers at UW-Madison printed 3D RAM devices for the first time ever in zero gravity. This is an important step for space exploration, according to the researchers, as astronauts will now be able to go deeper into space without having to worry about returning to Earth or waiting for a ship to deliver necessary replacement parts. 3D printing materials vary widely by use and application needs but adhesive ingredients play an important role, acting as both a binder and as a means to secure parts perfectly in place during the additive build to ensure accurate finished products.

3D printing in space has its unique challenges of course and during space missions, astronaut kits understandably see their fair share of wear and tear, which is why, until now, they had to rely on sources on earth to collect replacement hardware components, repairs, and maintenance. When traveling into deep space, quickly popping back to Earth or waiting for parts to arrive won’t be feasible.

A potential solution has always been the in-space 3D printing of any replacement electronic components required, like actuators, semiconductors, and sensors. However, this is not as easy as it sounds. In order to print an object with a 3D printer, the process relies on gravity to extrude the filament from the nozzle. In this NASA-funded project, the researchers were tasked with finding a way to remove the reliance on gravity in additive 3D printing.

Additive manufacturing in zero-gravity requires a slightly different approach than traditional 3D printing, so the team developed a process called EHD (electrohydrodynamic) printing. This entails the printing filament being electrically pushed out with more force than a standard 3D printer, and through a much thinner nozzle with a diameter of just 30 micrometers. Adhesive materials within many of the raw ingredients ensure binding and longevity.

The tension created by the tiny nozzle prevents the material from seeping out in a zero gravity environment, while the electric force allows the filament to break out of this tension. In addition to in-space 3D printing, another perk of EHD is its ability to create nanoscale patterns. 

To test out the technology, the team performed a series of parabolic test flights on the G-Force One jet at Florida’s Fort Lauderdale-Hollywood International Airport. These 40-minute tests consisted of ascents and dives that mimic zero-gravity conditions. 

During the first couple of flights, the team stumbled upon a technical glitch involving the plane engine vibrations interfering with the 3D printer’s calibration sensors. They spent long days and nights over the period of a week trying to resolve the issue which they did by changing some of the code (in zero-gravity, no less) to factor in these vibrations.

The third flight test was successful with the team managing to create over 12 items using a semiconducting ink (zinc oxide), and six more with an insulating polymer ink (polydimethylsiloxane). While floating around the cabin, the researchers were able to see the printer in action, but could only confirm the project’s success when they returned to the airport hangar and looked through a microscope.
3D Printing in Space Project

The project is led by Hantang Qin, the UW Industrial and Systems Engineering Assistant Professor, along with researchers from Arizona State University, Iowa State University, and Intel, among other industry partners.

Qin’s team of researchers, a mix of graduates and PhD students (namely, Khawlah Ahmad Alharbi, Xuepeng Jiang, Jacob Kocemba, Renjie Nie, Rayne Wolf, and Pengyu Zhang) are planning to go back to Florida later this year to conduct another two test flights. 

These will involve trying to kit out a multi-tool 3D printer with EHD, and subsequently moving from printing single units to complete semiconducting devices. All going well, this innovative technology will be ready for testing on the International Space Station.

Source: UW-Madison