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Comment by tzfld | Hacker News Reader

Wondering if a complex machine like an orbital rocket could be 3D printed as a whole and not just the components separately...

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Sintering (the most popular industrial 3D printing process) typically involves a substantial manual/machining component after the print. Also any precision elements or bearings rule out 3D printing. So, no.

Not only that, but sintering is also (generally) a lot less sturdy than a completely machined part.

The new sintering processes and alloys have gotten amazingly close for most purposes to be indistinguishable in application. Like any additive process, it still often requires machine work where precision is important.

Tht said... I am sad to see that lately, casting being overlooked often when it is still the best choice in many projects just because '3d printed' sounds better in the marketing. I have in front of me a 1960s magnesium alloy casting from the early 60s and the quality would make most sinterig operaters beyond jealous. Not to mention the material properties.

Yes, diecast components can be very precise. At the same time diescast process is cheap enough that 3D printing has no edge there.

Where 3d printing really helps is replacing wax or investment casting necessary for high melting point materials. You end up having quicker turnaround, better part quality and sometimes even lower price.

I think it's important to print different things at different scales because smaller printers are more precise.

Rocket Lab uses an engine that is mostly made by 3d printing: https://en.wikipedia.org/wiki/Rutherford_(rocket_engine) (Not as one piece though)

SpaceX also 3D prints the SuperDracos [0].

[0] https://en.wikipedia.org/wiki/SuperDraco#Manufacturing

If we are just looking at whether it could be 3D printed, I think the answer is that eventually anything could be 3D printed.

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