“3D printing” also known as additive
manufacturing is defined by ASTM as
the "process of joining materials to make objects from 3D model data, usually layer upon layer, as
opposed to subtractive manufacturing methodologies,
such as traditional machining. Synonyms
include additive fabrication, additive processes, additive techniques, additive layer manufacturing, layer manufacturing, and freeform fabrication".
In manufacturing,
and most especially of machining,
subtractive methods have often come first. In fact, the term subtractive manufacturing is a retronym developed in recent years to
distinguish traditional methods from the newer additive manufacturing
techniques. Although fabrication has
included methods that are essentially "additive" for centuries (such
as joining plates, sheets, forgings, and rolled work via riveting, screwing,
forge welding, or newer kinds of welding), it did not include the information technology component of
model-based definition; and the province of machining (generating exact shapes
with high precision) was generally subtractive, from filing and turning through
milling and grinding.
The use of additive manufacturing takes virtual
designs from computer aided design (CAD)
or animation modeling software, transforms them into thin, virtual,
horizontal cross-sections and then creates successive layers until the model is
complete. It is a WYSIWYG process where the virtual model and the
physical model are almost identical.
With additive manufacturing, the machine reads in data
from a CAD drawing and lays down successive layers of liquid, powder, or sheet
material, and in this way builds up the model from a series of cross sections.
These layers, which correspond to the virtual cross section from the CAD model,
are joined together or fused automatically to create the final shape. The primary
advantage to additive fabrication is its ability to create almost any shape or
geometric feature.
Domestic 3D printing is mainly for hobbyists and
enthusiasts as of 2012, rather than practical household applications. Designs
such as a working clock have been made, not as a practical, or particularly
accurate timepiece, but as an interesting project. Gears have been
printed for home woodworking machines and other purposes. 3D printing
is also used for ornamental objects. One printer (the Fab@Home) makes a point
of including chocolate amongst the materials that can be printed. Web sites
associated with 3D printing tend to include backscratchers, coathooks, and so
on. The RepRap Web site includes such examples. The Fab@Home gallery had many
objects without practical application, but included examples of what is
possible such as a flashlight/torch using conductive ink for
the electrical circuit, a battery-powered motor, a case for aniPod, a
silicone watch band, and a translucent cylinder completely enclosing a brown
box, something difficult to fabricate any other way.
Miniature human face models made through 3D Printing
The open source Fab@Home project has developed
printers for general use. They have been used in a research environment to
produce chemical compounds with 3D printing technology, including new ones,
initially without immediate application as proof of principle. The printer
can print with anything that can be dispensed from a syringe as liquid or
paste. The developers of the chemical application envisage that this technology
could be used both in industry and for domestic use, so that "people in
far-flung regions could make their own headache pills or detergent. The
technique might also allow people to print and share recipes for niche
substances that chemical or pharmaceutical companies don't make – because there
aren't enough customers, or they simply haven't dreamed up those ideas."
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