Comment by ecshafer
14 hours ago
I find it mind boggling that you can 3d print rocket engines. I thought that the standard line is that 3d printing metal wasn't developed enough for anything serious. Not a mechanical/materials engineer, but if you can 3d print rockets what's off the table? Jet Engines and that's about it I think?
From the article links, I am amused that SpaceX uses cybertrucks to tow their rocket engines around the grounds and not a normal cheaper truck. They also do it in a totally uncovered trailer, which must be good for the guys taking pictures for forums. But isn't that also good for guys taking pictures for competitors / Russians/ China?
> I thought that the standard line is that 3d printing metal wasn't developed enough for anything serious.
This hasn't been true for over a decade. High value relative to weight, highly complicated internal geometry, or repeated need for one off parts are all reasons to choose 3d printing today for production parts.
> I am amused that SpaceX uses cybertrucks to tow their rocket engines around the grounds and not a normal cheaper truck
If they buy $131M worth of Cybertrucks[1], they might as well use it for something...
[1] https://www.businessinsider.com/spacex-bought-tesla-cybertru...
3D printed metal components are also in Hyper cars, Bugatti and Koenigsegg have implemented them for different components
https://newsroom.bugatti.com/en/press-releases/bugatti-refin...
Apple uses some 3d printed components at volume, i.e. the ultra 3 and 4 watch cases.
Beehive is 3D printing jet engines today, albeit small and potentially only going one way.
Why would you want a yet engine to go backwards?
I think by one way they are referring to cruise missiles i.e. the engine is only used once or twice. Once during test fire, and once in production environment.
3d printing metal has some strength downsides, I'm not sure what it is for the raptor engines, but I've heard other space companies claim ~5% less strength that traditional methods for aluminum structures, but that can be worth it in cases where you are able to make shapes that wouldn't be possible with traditional methods, or if you save enough money by printing it. Rocket engines often can benefit from intricate internal channels and shapes that you can 3d print as once piece with no way to do it via subtractive manufacturing.
It has mild strength downsides, but very severe fatigue and damage tolerance downsides. Knowing this, it makes sense that 3d printing tech would make headway in space industry but not (yet) in aviation
What's the current theory for why this is?
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One of the things that 3-D printing allows is a fine honeycomb structure. This comes with a somewhat bigger strength reduction, but a dramatic weight reduction. Less materials is cheaper.
Also subtractive manufacturing requires paying to melt away a lot of metal. 3D printing saves.
I don't know all of the ways in which SpaceX is using
What makes jet engines less printable than rocket engines?
GE9X aircraft engines have 3D printed low pressure turbine blades, so I think the view that jets are somehow exceptional is already disproven. There are real benefits to using additive processes for turbojet/fan applications: many jet components have intricate passages and bizarre shapes to conduct gasses, and they are hideously expensive to manufacture with conventional tools.