Glossary
Metal 3D printing — definition
Additive manufacturing in which the part is built up layer by layer from metal powder, with no tooling.
The great advantage is that tooling cost is zero. That makes the method superior for prototypes, one-offs and the very smallest series, and it is the best way to test a geometry before committing capital to a casting tool.
The great disadvantage is cost per part. Build time is long and powder is expensive, and the price barely falls with volume. As soon as the series passes a few dozen parts, printing quickly becomes more expensive than casting.
Practical advice: use printing to confirm the part works, and cast it once you know it does.