Even though Star Trek replicators are still a few centuries away, it looks like a device called the Electron Beam Freeform Fabrication (or EBF3 for short) could help future lunar colonists create the tools they need on site without having to radio Earth for supplies.
(NASA) Electron beam freeform fabrication (EBF3) is an emerging cross-cutting technology for producing structural metal parts that has been developed by researchers at Langley over the past four years. The EBF3 process uses a focused electron beam in a vacuum environment to create a molten pool on a metallic substrate. The beam is translated with respect to the surface of the substrate while metal wire is fed into the pool. A part is thus built directly from a computer file in a layer-additive fashion. This process has gained interest in the Exploration community for the astronauts to fabricate structural spare parts and new tools during long duration human exploration missions. DARPA has also expressed interest in EBF3 as a manufacturing process that could be used for building large space structures on-orbit.
Despite appearing on MSNBC, this NASA seems to have released info regarding this technology last May, although it seems to have received very little attention.