Larger titanium aircraft components are being manufactured faster with selective laser melting 3D printing technology from SLM Solutions NA Inc. (Novi, MI). A 3D-printed titanium aircraft component measuring 12.21 × 8.74 × 8.66″ (310 × 222 × 220-mm) diameter is the largest part to date built in an SLM280HL. Dual 400-W lasers made it possible to build a part of this size in a relatively short timeframe compared to conventional manufacturing.
“This part is noteworthy because of its size and the fact that it was built out of titanium in six and a half days with no process interruptions,” said Mike Hansen, SLM Solutions applications engineer. “The fact that our SLM machine can operate for that period of time without requiring cleaning or experiencing any interruptions, is, in itself, extremely significant.”
SLM Solutions has increased the size of the build chamber and the build plate size to 280 × 280 mm, making the larger-sized part possible. “Advancements in 3D printing using titanium are particularly critical because it is a material that is normally very hard and thus subject to cracking due to high residual stresses, which was the real challenge. While the geometry wasn’t particularly complex the sheer mass of building something that large in titanium with the additive process was challenging,” Hansen said.
The dual overlapping laser technology developed and patented by SLM Solutions enables two lasers to work simultaneously on the part in the overlap area, producing not only a faster build but a larger part as well. The company carried out tests on these overlap areas showing there is no difference in quality between the area built exclusively by one laser and the area in the overlap worked on by both lasers interchangeably. SLM Solutions engineers went through several iterations to prepare the file and build some sample test pieces to see if the job could achieve the customer’s goal of cost and time savings, as well as weight reduction.
In general, aerospace/aircraft requirements for inspection are quite extensive, usually involving a computed tomography scan, a nondestructive test method, to check for porosity or voids in the part, or the customer may perform destructive testing by cutting up the part. “We used nondestructive testing on this part, then performed a real-world test by mounting it on an engine in its intended use, and running it until it failed,” Hansen said.
While 3D printing tends to get attention for its ability to build unique geometries, the nature of this aircraft component was not particularly complex. However, manufacturing a part of that size in titanium in such a short time was something that could not have been achieved had the part been machined out of a billet. “With additive manufacturing you’re not restricted to traditional tools and machinery, so you can design in more organic shapes and the entire cycle of designing and engineering a critical part for the aircraft industry is condensed considerably,” Hansen said.
According to Richard Grylls, head of the applications engineering department/North America technical director, “The part’s size meant that it would have taken several weeks to machine conventionally, given that it would have required four or five setups, and it would have been a costly process. Casting the part would have taken even longer given that the tooling would have to be built, which could take as long as six months. And traditional tooling is expensive. We were far faster even though the cost was more. Still, in terms of the total time saved the cost is worth it for a critical part of this size.”
A recent study funded by the US Department of Energy Advanced Manufacturing Office demonstrated that aircraft weight can be reduced by 7% by replacing conventional means of manufacturing with additive manufacturing—a remarkable number for an industry where most weight efficiency improvements are generally one or two percentage points.
“Within 20 years, there will be a seismic shift in how we manufacture for the aerospace and defense industry,” said Brian Neff, managing partner of Neff Capital Management who recently established a new company, Sintavia LLC (Davie, FL), to focus on the additive manufacturing of production parts for global aerospace and defense OEMs. “However, producers who do not understand or are incapable of producing parts with repetitive quality will not play a role in the OEM supply chain,” said Neff.
To support the production of highly complex metal parts, Sintavia added three Selective Laser Melting SLM 280HL systems from SLM Solutions, one with a single 400-W laser and two with twin lasers of the same power. With a 280 × 280 × 350-mm build envelope, the SLM 280HL system offers options to configure a single 400 or 700-W laser as well as dual (400 + 1000-W), or twin (400 or 700-W) lasers. Likewise, the system’s open software controls, bi-directional loader, and closed-loop metal powder handling achieve the speed, safety, and flexibility needed to optimize strict production parameters.
Sintavia will use the SLM technology to produce parts to the exacting quality control standards required by the aerospace and defense industry. In addition to a serial production capability, the company maintains a state-of-the-art metallurgical and metrology lab. “We are excited to be a part of the coming industrial revolution within the aerospace and defense industry,” said Neff. “Over the next few years, as more and more production is shifted to additive manufacturing within this industry, serial manufacturers with exceptional quality control, like Sintavia, will be in high demand by the OEMs.”
As the additive manufacturing industry evolves, SLM Solutions is seeing greater demand for more and more applications. However the materials and the process of producing these parts are advancing so fast that the standards are quickly becoming outdated. “We’re being contacted by more companies used to traditional manufacturing that now need to increase speed and throughput while maintaining quality, and who want to convert conventionally manufactured parts into additive manufacturing,” said Hansen.
“This industry is changing on a day-to-day basis, evolving very quickly, but there is a disconnect between the pace of the evolution in additive manufacturing and the ability of some industries to keep pace with approving new materials and processes, particularly the aerospace and automotive industries,” said Hansen. “Meeting the stringent quality requirements and material specifications with titanium in highly regulated industries like aerospace and automotive involves much testing of the materials and optimizing the parameters in order to make sure the customers get what they need,” Hansen said.
For more information about SLM Solutions NA Inc., go to www.slm-solutions.us, or phone 248-243-5400.
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