A flyswatter, a coat hook, a pair of sandals — all were made from the same unremarkable white plastic, the sort mass produced by the freighter-load in Guangzhou or Taipei. At a glance they couldn’t seem less significant. But these simple objects were “printed” in extruded plastic by a machine called RepRap. To its proponents, the machine may be as momentous as the Wright Flyer or the Altair home computer. Some claim RepRap could end poverty and halt global warming. This is because RepRap, which can be constructed for a few hundred dollars and runs on open-source software, can make something far more significant than flip-flops. It can build itself. Well, almost.
RepRap, short for “self-replicating rapid prototyper,” is the brainchild of Adrian Bowyer, a senior lecturer in mechanical engineering at the University of Bath, in England. In 2004 Bowyer realized that one use for a rapid prototyper — a digital printer that builds 3-D objects out of extruded plastic — would be to make its own parts. That idea led him to the work of John von Neumann, the Hungarian mathematician who in the 1940s had posited a “Universal Constructor”: a theoretical machine that could build any object, including itself.
Bowyer’s first-generation RepRap, which looks like a space-age coffee table, is called Darwin; he built it on the strength of a mere $40,000 grant from the British government. With the exception of screws, a battery, a motor, and grease, RepRap makes all its parts. In May the first RepRap built of parts made by another RepRap was revealed at England’s Cheltenham Science Festival. Within minutes of its assembly, the copy was at work on a replica. Since then, Bowyer says, he and his colleagues don’t even know how many copies have been made. At least 100 have been produced around the world, from Brazil to Finland to Israel, and a lively web culture of users has sprung up around the machines.
Bowyer sees a key potential of the technology as the decentralization of all industrial production, which, he argues, will create unlimited wealth. One admirer compared its potential to “having a China on every desktop.” And each new generation of machines would evolve by what Bowyer calls artificial selection. The resulting combination of economic equalization and technological evolution could be “Darwinian Marxism,” although it could mean a future without intellectual property and no way to encourage innovation. Bowyer isn’t worried: “I realized if you’ve got a machine that copies itself, you’ve got to give it away anyway, because as soon as one of them is out there you’ve lost control over it.”
Science fiction author and blogger Cory Doctorow sees great potential in the distribution of low-cost production and the lack of control of knowledge. “It’s a feature, not a bug,” he says. But others have found self-replicating machines problematic: In a 1983 paper, Carl Sagan and William Newman posited that if unleashed, exponentially replicating interstellar probes would devour the galaxy in less than 2 million years. And there’s the chance that all that plastic will drown the world in junk.
Such visions of the future require a wholly self-reproducing machine, however, and according to Terry Wohlers, a leading industry consultant in the field of rapid product development, we aren’t there yet. “It’s an interesting project, but a relatively small percentage of the parts are self-replicated, and those are the easier ones,” says Wohlers.
“A perfect universal constructor would self-copy and self-assemble, just like a bacterium or a tulip,” says Bowyer. But self-assembly, like fabricating its own screws and batteries, was too complex a technical hurdle, so RepRap relies on humans to do the assembling. Bowyer likens the relationship to the symbiosis between insects and flowers. Indeed, a blurred line between technology and biology suits Bowyer well. “Planet Earth has been covered with machines that copy themselves for 3.5 billion years,” he says. “When you look at the way humans domesticate objects that copy themselves, it’s inevitably the case that we make them more compliant, we make them more productive, we mold them to our own requirements.”
Originally published September 23, 2008