[avmich]

> Cooling channels are built into it.

How would you build cooling channels into something like this?

[burfog]

Rolls Royce blade production: https://www.theengineer.co.uk/rolls-royce-single-crystal-tur...

Picture of blade and some process description: https://en.wikipedia.org/wiki/Turbine_blade

Picture of wax blade without cooling channels: https://en.wikipedia.org/wiki/Investment_casting

Company that uses DLP 3D printing for turbine blades: https://www.prodways.com/en/lost-wax-casting-of-turbine-blad...

[ThenAsNow]

Conventional ways to do this include casting or, as is done on the RL-10 and SSME, building the nozzle out of thin-walled tubes (very labor-intensive and expensive). 3D printing is the future here, but there's still lots of improvement required in terms of wall thickness and roughness control, not to mention build volume.

[avmich]

The previous phrase was that the part is lost-wax cast. To me it's interesting how one can build cooling channels in the part which is cast.