PITTSBURGH (December 20, 2018) ... Tungsten carbide is one of the most versatile metal compounds and is renowned for its durability and strength, making it perfect for cutting tools, boring machines, and surgical instruments. Although its use in additive manufacturing (AM), or 3D printing, would seem ideal, tungsten carbide is susceptible to fractures and breakage when exposed to the extreme laser melting process used in printing metals.
However, a recent award to the University of Pittsburgh and General Carbide Corporation in Greensburg, Pa. will enable research into better base powders and 3D printing methods for more effective and economical use of tungsten carbide in additive manufacturing.
The project was financed in part by a $57,529 grant from the Commonwealth of Pennsylvania's Department of Community and Economic Development (DCED) and the first round of the PA Manufacturing Innovation Program (PAMIP). Cost share from Pitt's Swanson School of Engineering and General Carbide will provide a total funding of $145,000. Principal investigator is Markus Chmielus, assistant professor and the student fellows are from the Department of Mechanical Engineering and Materials Science. The award will also fund two women materials science and engineering students Katerina Kimes (graduate) and Pierangeli Rodriguez De Vecchis (undergraduate) as fellows in fundamental and applied research.
"Additive manufacturing is increasingly adopted by industry to build highly complex metal parts, but the rapid local heating and cooling during energy beam-based 3D metal printing produces large thermal gradients which causes tungsten carbide to crack," Dr. Chmielus explained. "Binder jet 3D printing is more effective because it selectively joins powder particles with a binder, one microscopic layer on top of another and without any temperature fluctuations during printing."
Still key to utilizing tungsten carbide, however, is that after a part is printed, it needs to withstand a process called "sintering" and potentially "hipping" that will densify and harden it for use.
To achieve that goal, Dr. Chmielus and General Carbide will investigate various tungsten carbide base powders that can be utilized in a binder jet 3D printer, as well as optimize the printing process and subsequent sintering and hipping.
"This research will enable General Carbide to expand our portfolio with more complex and versatile parts at a lower cost by partnering with the Swanson School and leveraging its expertise in binder jet 3D printing and additive manufacturing process optimization," noted Drew Elhassid, Chief Metallurgist and Manager of Lab, Pressing and Powder Production at General Carbide. "Additive manufacturing is especially useful when needed to create the most demanding but low-count parts that we wouldn't necessarily build on a consistent basis."
"With the Manufacturing Innovation Program, the Wolf Administration aims to connect our best and brightest students with manufacturers to drive new technology and innovation in the manufacturing sector," said Sheri Collins, deputy secretary for technology and innovation at the Pennsylvania Department of Community and Economic Development. "As manufacturing processes become more and more complex, these projects will keep Pennsylvania at the forefront of manufacturing innovation."