3D printing was known as stereolithography, a process invented
in 1986 by Chuck Hull of 3D Systems. Variations of this process are still used.
It begins, like all 3D printing, with software that takes a series of digital
slices through a computer model of an object. The shape of each slice is used
selectively to harden a layer of light-sensitive liquid, usually with
ultraviolet light, to form the required shape. After each layer has been made,
the build tray lowers by a fraction, another layer of liquid is added and the
process is repeated until the object is complete.
Many other approaches have since been developed. Laser-sintering involves zapping layers of powdered plastic or metal with a laser to harden the powder in some places, but not others. Other machines use an electron beam in a similar way. An alternative process melts a metallic powder as it is deposited. This can be used to repair worn parts, such as turbine blades. Some machines operate a bit like 2D inkjet printers, jetting light-sensitive liquid materials to form layers and then hardening them. Some machines can print a dozen different materials in a single pass of the print head.
One of the most popular techniques is fussed deposition modeling (FDM), which is akin to a computer-controlled glue gun (pictured below). A heated nozzle extrudes a filament of thermoplastic, which sets as it cools. Multiple heads can extrude different colors FDM is the mechanism used in many of the small 3D printers used by hobbyists, some of which now cost less than $ 1,000. More capable 3D printers cost tens of thousands of dollars, ad big industrials systems, like the laser-sintering machines capable of printing aerospace parts in titanium, cost as much as $1M.
Many other approaches have since been developed. Laser-sintering involves zapping layers of powdered plastic or metal with a laser to harden the powder in some places, but not others. Other machines use an electron beam in a similar way. An alternative process melts a metallic powder as it is deposited. This can be used to repair worn parts, such as turbine blades. Some machines operate a bit like 2D inkjet printers, jetting light-sensitive liquid materials to form layers and then hardening them. Some machines can print a dozen different materials in a single pass of the print head.
One of the most popular techniques is fussed deposition modeling (FDM), which is akin to a computer-controlled glue gun (pictured below). A heated nozzle extrudes a filament of thermoplastic, which sets as it cools. Multiple heads can extrude different colors FDM is the mechanism used in many of the small 3D printers used by hobbyists, some of which now cost less than $ 1,000. More capable 3D printers cost tens of thousands of dollars, ad big industrials systems, like the laser-sintering machines capable of printing aerospace parts in titanium, cost as much as $1M.
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