Stereolithography History
Stereolithography (SLA or SL; also known as stereolithography apparatus,
optical fabrication, photo solidification, solid free-form fabrication,
solid imaging, rapid prototyping, resin printing, and 3D printing) is a
form of additive manufacturing technology used for creating models,
prototypes, patterns, and production parts in a layer by layer fashion
using photopolymerization, a process by which light causes chains of
molecules to link together, forming polymers.Those polymers then
make up the body of a three-dimensional solid. Research in the area had
been conducted during the 1970s, but the term was coined by Charles
(Chuck) W. Hull in 1986 when he patented the process. He then set up 3D
Systems Inc to commercialize his patent.
Stereolithography or "SLA" printing is an early and widely used 3D
printing technology. Also known as Rapid Prototyping, 3D printing was
invented with the intent of allowing engineers to create prototypes of
their designs in a more time effective manner.
The 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.
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.
However, the term “stereolithography” was coined in 1986 by Chuck
Hull. Chuck Hull patented stereolithography as a method of creating
3D objects by successively "printing" thin layers of an object using a
medium curable by ultraviolet light, starting from the bottom layer to
the top layer. 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, Hull founded
the world's first 3D printing company, 3D Systems Inc, which is
currently based in Rock Hill, SC.
Stereolithography's success in the automotive industry allowed 3D
printing to achieve industry status and the technology continues to find
innovative uses in many fields of study. Attempts have been made
to construct mathematical models of stereolithography processes and to
design algorithms to determine whether a proposed object may be
constructed using 3D printing.