Many examples of modern technology are older than we think. For example, capacitive touchscreens were developed in the 1960s to improve aerial radars. And decades before you could buy a 3D printer for your home, engineers were pioneers in prototyping objects quickly.
Depending on who you ask, the first 3D printer was either 1981 or 1986. Dr. Hideo Kodama invented the “3D printer” in 1981, which deposited a resin layer by layer and cured it with UV light. Meanwhile, the 1986 model, although working on the same principle (now known as stereolithography), was patented by Charles Hull. As such, many people recognize Hull as the grandfather of 3D printing.
Obviously, the developments do not stop there. In 1988, Carl Deckard, then a student at the University of Texas, created a form of 3D printing known as selective laser sintering, a process by which a laser solidifies a powdered material into a solid object. And in 1989, Scott Crump developed the most recognizable form of 3D printing: fused filament manufacturing (that is, melting spools of plastic and dropping the results onto a platform to build an object layer by layer).
Inspiration takes many forms
Every artist and inventor has his muse. Some inventions were inspired by science fiction, after engineers wanted to transform science fiction into scientific reality. Other inventions, like the 3D printer, come from places closer to home.
When Chuck Hall told the National Inventors Hall of Fame how he invented his version of stereolithography, he said his idea came from his workplace, which used UV light to add a thin plastic veneer to furniture. He wondered if the same technology could be used to “stack thousands of thin layers of plastic on top of each other” and create a shape with UV light. It took some convincing, but Hull’s boss finally approved the idea and let him work on the project… on the condition that Hull did it in his free time.
Initially, Hull thought his 3D printer would only make temporary parts – quick prototypes of items that would be replaced with more durable injection-molded versions. His work eventually led to a system that transmitted UV light into a vat of photopolymer, and thus stereolithography as we know it was born. But Hull’s work doesn’t stop there. He also invented the photopolymer material used in resin printers called SLA, the .stl file format used by most 3D printers, and the world’s first commercial 3D printer, the SLA-1.
A lasting legacy
3D printing has evolved by leaps and bounds since the 80s. Today, you can 3D print houses and use a 3D pen to extrude molten plastic in free form instead of sticking to an electronic blueprint. And while many people still use stereolithography for their prints, the original SLA-1 is long gone. But like the dinosaurs, it is preserved for posterity.
While fused filament manufacturing is currently the most popular form of 3D printing, SLA printing was the original method of rapid prototyping, especially for professionals. This was mainly due to the way it worked: a UV laser bounced off a mirror to cure the photopolymer in a vat, and an elevator in the vat lowered the part so the laser could start on the next layer. This method required large tanks, which limited these printers to industrial environments. However, the process has been reversed using reverse stereolithography. This new iteration uses a series of mirrors to shine the UV laser onto a thin layer of SLA on a platform, which then lifts the part out of the resin tank so the laser can cure another layer below. This method quickly became the stereolithography industry standard thanks to its smaller resin tanks and cheaper price.
As 3D printing progressed, particularly with the advent of inverse stereolithography, SLA-1 was gradually phased out. However, you can find these relics of early 3D printing on display at museums such as the National Inventors Hall of Fame Museum in Alexandria, Virginia. Although the Henry Ford Museum (in Dearborn, Michigan) presumably owns an SLA-1, this particular model is stored somewhere in the annals of the museum’s collection and is not available for public display.
