> Besides, the question I have is why 3D printing? My understanding is that there's interesting things in the aerospace industry that are very difficult or som

> Besides, the question I have is why 3D printing? My understanding is that there's interesting things in the aerospace industry that are very difficult or sometimes impossible to machine from a single part in a conventional subtractive machining process. GE is doing it as well for the LEAP engines: https://3dprintingindustry.com/news/ge-aerospace-to-scale-the-production-3d-printed-jet-engines-with-650-million-investment-228977/ https://3dprintingindustry.com/news/ge-aerospace-to-scale-th... As an easy example, imagine a single-piece rocket nozzle with internal channels for delivering fuel and oxidizer. Pretty much impossible to machine and not that big of a deal* to do with additive manufacturing. * Your mileage may vary, talk to your doctor for details. :)