Over the past ten years a research team at the Beijing University of Aeronautics and Astronautics has been working to develop a Laser Metal Deposition (LMD) 3D printer capable of producing large titanium parts suitable for military and aerospace industries.
The researchers, led by Professor Huaming Wang, received funding from multiple sources, including the PLA General Armament Department, the Commission for Science, Technology and Industry for National Defense, the National Natural Science Foundation and the "973" and "863" programs. In return they developed a mammoth 3D printer that uses a process called Laser Engineered Net Shaping (LENS) to build objects made from titanium and other metals. The LENS printing process involves directing a high power laser beam through the print head while metal powder is simultaneously fed into the build area.
Professor Wang's team had to overcome multiple challenges to produce the printer including developing an inert gas protection system for the extruded metal powder, controlling the rapid solidification of microstructures and preventing internal defects during the laser melting deposition process. In the end, the project was successful and the team was honored with first prize in the State Technological Invention Awards in China earlier this year. "Although scientists in other countries know how to print smaller parts from titanium alloys, we made the technological breakthrough for larger components that can be used in planes," Professor Wang said.
The build area for Wang's LENS printer is pretty impressive. The exact measurements have not been publicly released but the team has displayed aircraft parts up to thirteen feet long that were built on the printer. As if the sheer size of the printer weren't impressive enough, the 3D printed parts can cost up to 90% less to produce than traditionally manufactured parts. "This new 3D printing method is an efficient tool to help improve manufacturing levels and, as such, can play a major role in upgrading China's high-end industries." Wang said.
Although China currently holds the title of "Largest titanium part ever produced on a LENS printer," they are not the only ones using the technique. In the United States smaller LENS printers are being used to produce hardware components for aerospace fighter jets and NASA is using a similar laser printing process to produce parts for their space shuttles.
If you'd like to know more about how LENS 3D printing works you can take a look at the video below. It's produced by Optomec, an additive manufacturing company with headquarters in Albuquerque, New Mexico. They sell 3D printers (including LENS printers) in fifteen countries. The printer Optomec is showing off is the LENS 850R. It's much smaller than the one designed by Professor Wang's team, but the printing process is the same. Build footage starts at 2:40.