Stereolithography or “SLA” printing is an early and widely used 3D printing technology. The word is a portmanteau of the Greek words “stereon” (solid), “lithos” (stone) and “graphy”. Also known as additive manufacturing (a method of Rapid Prototyping), 3D printing was invented with the intent of allowing engineers to create prototypes of their designs in a more time effective manner.
technology first appeared as early as the 1970s. Japanese researcher Dr. Hideo Kodama first invented the modern layered approach to stereolithography by using ultraviolet light to cure photosensitive polymers.
On July 16, 1984, three weeks before Chuck Hull filed his own patent.
Alain Le Mehaute, Olivier de Witte and Jean Claude André filed a patent for the stereolithography process.
The French inventors’ patent application was abandoned by the French General Electric Company (now Alcatel-Alsthom) and CILAS (The Laser Consortium). Le Mehaute believes that the abandonment reflects a problem with innovation in France.
Mr. Hull’s patent described a concentrated beam of ultraviolet light focused onto the surface of a vat filled with a liquid photopolymer. The UV light beam is focused onto the surface of the liquid photopolymer, creating each layer of the desired 3D object by means of crosslinking (or degrading a polymer).
In 1986, Mr. Hull founded the world’s first 3D printing company, 3D Systems Inc. which is currently based in Rock Hill SC.