Page 26 - 3D Metal Printing Summer 2016

3D Titanium Taking Off
Andrew Heidloff, was acquired by Praxair Surface Technologies in 2014; Heidloff and Riecken joined Praxair as develop- ment specialists.
“We’re the first to employ close-coupled gas atomization for titanium,” Heidloff tells 3D Metal Printing, “which is the opti- mum process for making powders fine for additive manufacturing. The nozzle that conveys the liquefied titanium through the high-velocity atomization gas is the key to the process, allowing the tem- perature of the metal to increase to super- heating range—100-150 deg. above melt- ing temperature.”
Documented Metal-AM Results
While the overwhelming majority of titanium-related additive-manufacturing projects remain under wraps, several have recently been documented. Included is the 3D printing of titanium-aluminide rotor wheels for use in automotive tur- bochargers, using Arcam’s electron-beam- melting technology. The new turbochargers, compared to those currently fabricated from conventional nickel superalloys, promise to reduce weight by 60 percent and mass by 36 percent, while improving vehicle efficiency by 5 percent and reduc- ing CO2 emissions by 8 percent.
Arcam’s electron-beam melting of tita- nium also has received notoriety related to additive manufacturing of jet-engine turbine blades for the GE Aviation LEAP
engine, developed by CFM Intl. GE states that one Arcam machine can manufacture eight turbine blades in 7 hr., thanks to the ability of the electron-beam machine to build up layers of powder that are more than four times thicker than those pro- duced by laser powder-bed machines. This on the heels of GE’s opening of a 300,000-sq.-ft. plant in Auburn, AL, where more than a dozen laser-melting 3D print- ing machines produce LEAP fuel nozzles.
Most recently, the new Airbus A380 is powered by the Rolls-Royce Trent XWB- 97 engine, which features a prototype front bearing housing (1.5-m dia. by 0.5 m thick) containing 48 airfoils 3D printed (using Arcam technology) from titanium.
Additionally, visitors to the Consumer Electronics Show in Las Vegas earlier this year got to see the 3D-printed titanium bicycle frame produced by Tokyo-based Cerevo Inc. It, like so many aircraft appli- cations, marries titanium to carbon-fiber components.
And, finally, the U.S. Navy’s latest unmanned combat aerial surveillance sys- tem (the X-47B) features a warm-air mixer (fabricated by Simi Valley, CA-based addi- tive manufacturer CalRam, Inc.) using Arcam’s electron-beam process. The com- plex component, described in a recent article in Aerospace Engineering, is made from one piece by 3D printing Ti-6Al-4V powder. The benefits: part-count reduc- tion and the elimination of welding of
multiple parts, as well as reduced costs and a shortened delivery schedule.
Out-of-the-Box Designing
Ti-6Al-4V is one of the three titanium powder compositions offered by Praxair Surface Technologies for additive manu- facturing, the others being titanium alu- minide (Ti-48Al-2Nb-2Cr), and Ti6242 (Ti- 6Al-2Sn-4Zr-2Mo).
“Our Ti-6A1-4V materials are by far the biggest sellers of the three products,” says Shives.
“In terms of what we see coming down the road,” he adds, “we expect to see sig- nificant growth in design complexity in several end-use application areas. Additive manufacturing with titanium and other metal alloys allows designers to think out of the box and develop more organic- looking shapes that give fresh perspectives to functionality and performance.”
Heidloff adds:
“We’ll see more opportunities to com- bine multiple parts into one functional design while providing lightweighting and strength advantages. We expect our core group of three titanium-alloy addi- tive-manufacturing powders to find a home in many of these new applications, and also expect that our new group will find additional opportunities to develop custom alloys for our customers, in what is sure to become a customer-driven market.” 3DMP
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“We’ll see more opportunities to combine multiple parts into one functional design while providing lightweighting and strength advantages. We expect our core group of three titanium-alloy additive-manufacturing powders to find a home in
many of these new applications.”
Development specialists Joel Rieken (left) and Andrew Heidlof, while at Iowa Powder Atomization Technologies (IPAT), developed the special nozzle that enables close-coupled atomization. Looking toward the future of 3D metal printing, Heidloff says: