Additive manufacturing (3D printing) is rapidly expanding. Originally restricted to the production of plastic artifacts, it can now be used to print whole jet engines, turbine blades, and aircraft parts, medical implants and other applications. Its use is being extended to food, human organs and even, so it is said, to entire houses! James Chater recently reported on the implications for nickel and super alloys.
Additive manufacturing (AM) is entering the mainstream. For years companies have been pioneering the various techniques of AM and many have got as far as using it for prototyping, while holding off from AM mass production for the time being. Now companies are starting to take the plunge and integrate AM into their mass production.
A clear leader among the large companies is GE, which is already using 3D technology to manufacture the elaborate interior of the fuel nozzles for its LEAP aircraft engines. More recently, the FAA recently cleared GE’s first 3D-printed part for a commercial jet engine, a sensor housing. Now MTU Aero Engines is 3D-printing the boroscope bosses for the A320neo engine, made by Pratt & Whitney.
Meanwhile engineers at Australia’s Monash University claim to have produced the world’s first 3D-printed jet engine, using the selective laser sintering (SLS) process. The university is collaborating with companies such as Airbus, Boeing and Raytheon to develop new components with 3D printing.
Several companies are investing to take advantage of the aerospace boom and the rapidly advancing 3D printing techniques for special alloys.
AM techniques have gradually extended to include various types of stainless steels, maraging steels (17-19% nickel), pure titanium, titanium alloys, pure nickel, nickel alloys and several other special materials. Among superalloys, the most frequently encountered in AM processes are Inconel 718 and 625. Alloy 718 is especially favoured for aerospace parts and gas turbines, two areas in which the advantages of AM are especially significant. Alloy 625 is used in the aerospace, chemical and energy markets, with applications including gas turbine blades, filtration and separation, heat exchanger and moulding processes. Other nickel-containing materials being produced for 3D printing include Hastelloy X, Kovar (a Fe-Ni-Co alloy used in lighting) and Invar 36. EOS has developed a new alloy, NickelAlloy HX, specifically for 3D printing.