The debate about additive versus traditional manufacturing will always go back and forth. The answer, of course, depends on the application. For International Submarine Engineer (ISE) Ltd., though, using additive over traditional manufacturing cut time and cost out of the production of a titanium Variable Ballast (VB) tank. Electron Beam Additive Manufacturing (EBAM) from Sciaky, Inc., a subsidiary of Phillips Service Industries, Inc. (PSI), was the additive technology used in this example.
The titanium VB tank is a sub-system of ISE’s Arctic Explorer Autonomous Underwater Vehicle (AUV) class of vehicles. ISE previously built two Arctic Explorers for Natural Resources Canada/Defence Research and Development Canada (DRDC) to map the sea floor underneath the Arctic ice shelf in support of Canada’s claim under Article 76 of the United Nations Convention on the Law of the Sea.
The Arctic Explorer is the largest of the Explorer AUV class, measuring more than seven meters (nearly 23 feet) long and weighing more than 2000 kilograms (4409 pounds). It can be launched from a ship or through an ice-hole and the modular sections can be separated for transportation.
The VB system can park on the sea floor or hold itself on the underside of the ice during missions. Rated to 5,000 meters (roughly 3.11 miles) depth, the Arctic Explorer is designed to remain underwater between missions for extended periods of time. A small Remotely Operated Vehicle (ROV) conducts all servicing and charging after the AUV is attached to a docking head.
When ISE’s former supplier closed, the engineers needed to find a new supplier. They turned to Sciaky after hearing it had 3D printed titanium propellant tanks for Lockheed Martin Space Systems in 2015.
The Sciaky EBAM machine is a highly scalable metal 3D printing system. It can produce parts ranging from 8 in. (203 mm) to 19 ft (5.79 m) in length. It has a gross deposition rate ranging from seven to 20 lb (3.18 to 9.07 kg) of metal per hour.
EBAM also includes an Interlayer Real-time Imaging and Sensing System (IRISS), a real-time monitoring and control system. It can sense and digitally self-adjust metal deposition with precision and repeatability. This closed-loop control is the primary reason that Sciaky’s EBAM 3D printing process delivers consistent part geometry, mechanical properties, microstructure, and metal chemistry, from the first part to the last.
Sciaky helped ISE reduce production time from 16 weeks to 8 weeks, and reduce overall costs compared to retooling with a new forging supplier. In addition, the VB tank created with the EBAM process passed the same vigorous qualification testing as the tank previously created with the forging process. ISE now plans to 3D print other critical titanium parts with Sciaky’s EBAM process.
The 3D printed VB tank will be installed onboard a new Arctic Explorer AUV that is scheduled to be delivered to the University of Tasmania in the spring of 2017. This new Explorer AUV will be deployed in Antarctica after extensive trials and training operations.