Additive manufacturing

Building parts layer by layer directly from a digital model, commonly called 3D printing.

• Material goes only where it is needed, so complex internal shapes such as cooling channels and lattices need no moulds or tooling.
• Merging assemblies into one printed part is a key payoff; GE's LEAP jet-engine fuel nozzle replaced about 20 parts with one.
• Metal printing now makes rocket engine parts, aircraft brackets, and implants with porous surfaces that bone grows into.
• It is slow and costly at high volumes, and hidden pores or internal stresses demand extensive testing before critical use.