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How 3D Printing Works

12 To print a three-dimensional object, the work starts on a
computer. Three-dimensional computer-aided design programs,

or CAD programs, have been used by engineers and architects
since the 1970s. By the 1990s, three-dimensional CAD programs
were available on desktop computers.

13 There are several software programs that are available for
free, and you can use models to tweak and combine shapes to
create the object you want to make. For example, perhaps you
Plastic filament, below,
is used for 3D printing. want to create a model of an animal to use as part of a diorama
for a science project. You design this model on the computer,

then you send the design file to the printer. Check out the
process at right to see how it works.

14 Most home-based 3D printers use a process called Molten
Polymer Deposition (MPD). This means that plastic is melted

(becoming “molten polymer”), pushed through a print head that
looks somewhat like a needle, and then deposited on what’s
called a print bed in thin layers that are then built up to become
an object.

15 In commercial 3D printing labs used by scientists and
engineers, 3D printers can also use material like metal, plaster,
ceramic, and even edible materials like pizza dough or chocolate.

A medical designer
uses a CAD program
to design orthopedics
printed by a 3D printer
(in the foreground).

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