The solution is two standard 20 foot shipping containers containing a software controlled laser system that builds any metal part for which CAD (Computer Aided Design) files are available. A computer controlled machine tool then takes the laser generated (using powdered plastics, ceramics, rubber and metal) part and finishes it. The 3-D object creation technology is over two decades old, but until recently it was not capable of producing a metal part the equivalent of one that was forged or created with a machine tool from a block of metal. Actually, the 3-D technology was originally developed for the creation of prototype parts. Over the last three decades, CAD has become the standard for designing components. It was a small leap to realize that military forces in a combat zone are one organization that could economically use this technology to create parts on demand. There are thousands of different metal parts rattling around in military vehicles, equipment and weapons. The army has CAD files for most of these parts, as well as CAD files for the complete systems all these parts fit into. The new system is called the "Mobile Parts Hospital" (MPH) and the first one will be operating in Kuwait by the end of the year. The first MPH cost about $3 million.
Note that the MPH is a continuation of a long naval tradition. For centuries, warships took carpenters, and then machinists, to sea as part of the crew. If a part broke, you had sailors who could fabricate a new one. Armies used to do the same thing, using carpenters and blacksmiths to fabricate most parts on the spot. But when trucks and other high tech gear appeared, carpenters and blacksmiths were no longer able to deal with the many precision parts involved. Air Force units often took a machine shop to war with them, but armies had a lot more vehicles and items that could break, and moved around too much to make the machine shop approach work for them. The MPH takes us back to the future.
The U.S. Army is using off the shelf technology to manufacture spare parts on demand, in the combat zone. A major problem with keeping military operations going is obtaining a sufficient supply of spare parts. This sort of thing drives general's nuts, because there is no way to predict how the unique climate and geography of some distant battlefield will cause wear and tear on your vehicles and weapons and create a demand for certain spare parts. For example, in Iraq, the dust and heat conditions were unique to Iraq, and some components would fail more quickly than they had in, say, the deserts of the western United States, where U.S. Army units do a lot of their training. In Iraq, as in Afghanistan, there was a desperate scramble to fly over the needed parts so that the vehicles, equipment and weapons could be put back to work.