Distribution centers and jobbers couldn’t possibly afford to stock every single part that a truck owner might need at a given point in time. The massive inventory would tie up far too much space and capital. The best they can do is play a numbers game, focusing on parts used in the widest volume of vehicles, and trying to limit investments in the components that are likely to gather dust on a storage rack.

Everyone else has to wait.

But imagine a day when parts are emailed – rather than shipped — on demand.

Daimler’s Mercedes-Benz Trucks division has delivered us a step closer to that reality. This summer, European teams began using a 3D printer to create the metal thermostat cover for Unimog trucks that haven’t been produced for about 15 years. The part was made by spreading powdered aluminum and silicon in layers, fusing everything in place using a process known as Selective Laser Melting.

Daimler reports that the final product delivers the same functionality, reliability, durability, and cost-effectiveness as its traditionally produced counterpart. It’s only a matter of time before the process is used to make peripheral metal engine parts, in-engine parts, cooling system components, transmissions, axles or chassis, the company says.

With a broad network of printers, additive manufacturing like this could decentralize production, shorten delivery times, and reduce warehousing and distribution costs. Manufacturers, meanwhile, can use the process to refine and test evermore complex prototypes, in part because 3D printing builds things from the inside out.

This isn’t about printing a component while you wait at a parts counter, and mass-produced parts will always be cheaper, but 3D printing certainly makes it easier to source otherwise-rare components. Rather than building massive quantities at a time, manufacturers could create smaller batches, always with the latest upgrades to address things like recalls that have emerged. There’s no limit to the potential of customizing different parts, either.

It is hardly the fodder of science fiction. On the F1 racing circuit, WilliamsF1 partnered with German’s EOS to print gearbox casings and other parts for races. Companies from Audi to Honda are finding new ways to integrate the tools into their general manufacturing processes. Here in Canada, Kor Ecologic unveiled the prototype of a car that featured an entire body created with a 3D printer. And as reported in our August edition, Michelin has a vision of using a 3D printer to replenish or update tire treads.

There’s no limit to how far afield parts production might spread. In one recent test of 3D printing, NASA actually transmitted the file for a 4.48 x 1.29-inch ratchet wrench to the International Space Station. Four hours later, the final product was in hand.

It’s clearly a space-age concept that has a place here on earth.