If we've said it before, we'll say it again ... "3D Printing" is a set of niches within niches. Here is yet another emergent process .... liquid metal 3D printing using magneto-hydrodynamics Think 'inkjet' with liquid metal.
Start up Vader Systems believes it can bring this technology to market just as has occurred with RepRap style fused deposition modelling (FDM) of thermoplastics. They intend to start with aluminium, and then copper and zinc.
Traditionally metals are 'sintered' from powders. By contrast Vader Systems process will produce fully fused objects. If this works it will be super-cool. The company is aiming for the under $10K market. Listen to one of the founders talk about the potential advantages: