[This machine is amazing](http://singularityhub.com/2010/04/05/5-axis-robot-carves-metal-like-butter-video/). As the Singularity Hub article notes: a great deal of attention is focused on 3D printing, which is increasingly being done with metal, but there are moments where milled materials are superior. Is the gap close-able? If so, how long?
The difference between milling and printing is that with the former you start with a large chunk of material and then slowly carve out what you don’t need. Printing would seem to be more inefficient in which you only “print” or build up the material you need.