It may sound like science fiction, but some of us may soon be manufacturing products right in our very own homes. "Think about collectibles, customized gifts, interior decorating elements, customized headphones or earphones for cellular devices. Think about lighting fixtures—you might want to start a design shop," says Abe Reichental, CEO of 3D Systems. "The limit is really only your imagination."

Invented in 1986 by 3D Systems co-founder Chuck Hull, stereolithography in its simplest form uses a computer-controlled UV laser to form a complete three-dimensional object out of a vat of liquid UV-curable photopolymer resin. A stereolithography machine "prints" a three-dimensional computer file by directing its laser over the liquid photopolymer, one thin layer at a time. Exposure to the laser solidifies the pattern traced on the resin. Once a cross-section of the object is exposed, the machine lowers the hardened layer and a resin-filled blade sweeps across the cross-section, re-coating it with fresh layer of liquid. On this new liquid surface, a new layer pattern is traced, adhering to the previous layer. The final result is a complete three-dimensional object precisely resembling the original computer file.





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2012 may be the year of 3D printing, when this three-decade-old technology finally becomes accessible and even commonplace. Lisa Harouni gives a useful introduction to this fascinating way of making things -- including intricate objects once impossible to create.