Wire Arc Additive Manufacturing builds titanium pressure vessel for space exploration

The titanium pressure vessel was produced by Wire Arc Additive Manufacturing at Cranfield University

A team comprising of Thales Alenia Space, Cannes, France; Cranfield University, Bedfordshire, UK; and Glenalmond Technologies, Glasgow, UK, has successfully produced its first full-scale prototype of a titanium pressure vessel to be used in future manned space missions, produced by Wire Arc Additive Manufacturing (WAAM).

The 1 m tall, 8.5 kg part was produced in Ti-6Al-4V at Cranfield University, before being sent to Glenalmond Technologies for stress-relieving, laser-scanning, machining and ultrasonic inspection. Final inspection was then performed by Agiometrix, using CT for internal quality analysis and an optical scanner, with Thales Alenia Space ensuring that the part met the mechanical requirements and specifications of the application.

The use of WAAM enabled the team to integrate two individual pieces into a single part, eliminated the need for long-lead-time forgings, and substantially reduced the amount of waste material. If manufactured by conventional methods, the component’s production would have consumed roughly thirty times more raw material than its final mass, according to the team members. Using WAAM process, more than 200 kg of Ti-6Al-4V was saved for each item. The team noted that there is room to improve this further, and Cranfield was said to be working on innovative methods to deposit closer to the final thickness.

Following quality checks, the project team is satisfied that the vessel fulfils the technical and quality requirements for its application. A second prototype will now be produced, with the purpose of carrying out a fine tuning of the whole manufacturing cycle, to demonstrate the repeatability and reliability of the process, and to push the implementation of the new approach into the flight hardware.

Eng Massimo Chiampi, Study Manager for Additive Manufacturing projects at Thales Alenia Space, stated, “We were looking for an innovative manufacturing solution for the tanks, which typically suffer from long lead time with the conventional production route based on subtractive machining. Thanks to this project, we have demonstrated that the adoption of WAAM technology enhances the competitiveness of our product.”

“A near-net shape item is fabricated in few days — compared to several months needed for the procurement of the standard wrought products — and also the amount of machining operation is consistently reduced,” he continued. “We have achieved a 65% reduction on the overall lead time without giving up the requested performances and this provides a benefit also in terms of design flexibility, making it possible to answer customer needs at a late stage of the project.”