October of 2020 saw the launch of aerospace firmBoom Supersonic的XB-1飞机，有一个总共21个组件3D printed by PBF system OEMVELO3D。现在，该公司发布了一项全面的案例研究，可深入研究design, manufacturing, and finishing of the Concorde-esque supersonic aircraft.
Citing design flexibility, weight savings, and time savings as major factors in its choice to employ additive manufacturing, Boom fabricated some of the XB-1’s most complex parts usingVelo的蓝宝石3D打印机。
Design: optimizing weight and thermal efficiency
Most of the aircraft’s 3D printed parts are in some way related to channeling air, and feature complex internal geometries such as vanes, ducts, and louvres. Since the air being channeled often exceeds260°c，a基于表面的设计方法至关重要。
拜伦·杨, an engineer at Boom, explains:“如果快速移动的空气接触,我们关心阿布t that surface from an efficiency and performance standpoint. So when designing these parts, you generally start with aerodynamic profiles and then trim, fillet, and thicken surfaces to create the solid part itself. The resulting parts are very complex—which meant they definitely needed to be fabricated through 3D printing.”
The company’s unique flow-directing geometries were also designed with weight savings in mind – a concept that simply wouldn’t be feasible if sheet metal or casting were to be used. As such, many of the components featuredextremely thin walls, in the region of about 0.02 inches, or 750 microns.
According to Gene Miller, an application engineer at VELO, the impressive height to width ratios were made possible by the Sapphire’s non-contact recoater system: “Because our technology provides the ability to print that very high aspect ratio in this kind of design, we didn’t need excess material for strength inside the structures and we could grow those duct vanes up very high without any interference from the recoater.”
制造和后处理
The 3D printed parts were manufactured out of titanium, an aerospace industry staple known for its high strength and temperature resistance. Unfortunately, titanium is also known to become brittle and crack-prone when cooled too rapidly. This is where the Sapphire’s advanced process control capabilities reportedly came in handy, as the machine was able to automatically check critical parameters like laser alignment, beam stability, and powder bed quality mid-build.
Miller explains, “We reduced the amount of internal stress in the substrate as the material was built up in the Z build-direction. It diminishes the possibility of cracking by mitigation of internal stresses formed during cooling.”
Once printed, the parts were sawed off the build plate and post-processed with relative ease, owing to the Sapphire’s SupportFree 3D printing technology. Small crevices and channels were completely supportless, while larger holes required minimal handwork with a screwdriver or grinder. All in all, the machinists working on the parts spent just 30 minutes on post-processing per component. The surface finishes averaged about 250 RA on a profilometer, which Boom has been happy with so far.
Finally, the components were heat treated and hot isostatic pressed to improve their fatigue lives – this is especially important for flight components as they are under constant cyclic loading with takeoff and landing.
Young得出结论：“超音速飞行引入了许多不同的现象，并且通常在传统的航空旅行中看不到压力。施加的主要力通常不是打破声音屏障的压力负载。在许多情况下，这是由于飞机在您的零件周围弯曲的整体结构所致。”
Flight-critical components in the 3D printing industry
近年来，近年来，对航空航天航空航天和航空组件的3D打印与增材制造技术的进步一起运行。航空公司公司Honeywell Aerospacerecently received a Federal Aviation Administration (FAA) certification for its第一个3D打印的至关重要的发动机组件。＃4/5轴承外壳是ATF3-6 Turbofan发动机的关键结构组件，该发动机在达索Falcon 20G maritime patrol aircraft.
别处，NASAalso recently announced the successful completion of 23 hot-fire tests on two of its own关键的3D印刷航空发动机组件。The parts in question are a copper alloy combustion chamber and a specially developed iron-nickel superalloy nozzle.
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Featured image shows the XB-1 aircraft. Photo via Boom Supersonic.
