In this video of DARPA DMACE Challenge Sphere crushing event (December 8, 2010) you can see an animation of the machine used to digitally manufacture the titanium spheres.

The Arcam A2 use an electron beam melting process and Ti6Al4V titanium alloy powder.

“The Arcam A2 is designed for production of any functional part within Aerospace and General Industry. The parts are built up layer-by-layer of metal powder melted by a powerful electron beam. Each layer is melted to the exact geometry dictated by the 3D CAD model. The Electron Beam Melting technology allows for high energy to be used providing high melting capacity and productivity. Parts are built in vacuum at elevated temperatures resulting in stress relieved parts with material properties better than cast and comparable to wrought material” (Arcam.com)