NASA tested a 3D-printed rocket engine, and it worked.
Adam Rifkin stashed this in 3D Printers
3D printing parts of a rocket engine has some serious advantages.
Rocket engine components can be incredibly complex and they have to be made in amazingly precise shapes due to the high pressures and speeds they operate at. A flaw in a Russian-made engine, for example, is thought to have caused the recent crash of an Orbital Sciences rocket. But 3D-printed rocket parts, made well, can be produced without the need for welds or joins, and could even be designed to be more optimal for aerodynamics or fuel-flow. SpaceX, which just performed a historic landing of its Falcon 9 rocket, uses a few 3D-printed rocket parts in its Merlin rocket engines.
Now NASA has completed several test runs of what it calls a 3D-printed “breadboard” engine—various components of a fully working rocket engine strung together in a rig that looks nothing like a real, flyable rocket engine. Some 75% of the parts of this engine were 3D printed, and it worked just fine, as NASA’s thunderous videos demonstrate. With more research, this sort of low-cost rocket technology could seriously boost the commercial space business and could result in powerful, reliable engines that could help us on the way to Mars.
Top Reddit comment:
Significantly less material is used with a 3D printed component. A typical rocket engine component starts out as a big block of metal and is then iterated through numerous machining and other processing steps before it is complete. Eventually it is (most likely) welded to other components. These are all very time-consuming and expensive procedures, and it's this (not raw material costs) that constitute the vast majority of the cost of a rocket engine. If you can 3D print components instead, you not only realize savings in the materials, but also (and this is the big one) in eliminating machining, processing, and welding steps.
All that said, additive manufacturing in high-precision, harsh-environment applications like rocket engines is still very much in the early stages. It's going to be a long time before a significant portion of any rocket engine is fabricated using additive manufacturing.