Terminology
The umbrella term
additive manufacturing (AM) gained wide currency in the 2000s, inspired
by the theme of material being added together (in any of various ways).
In contrast, the term subtractive manufacturing appeared as a retronym
for the large family of machining processes with material removal as
their common theme. The term 3D printing still referred only to the
polymer technologies in most minds, and the term AM was likelier to be
used in metalworking and end use part production contexts than among
polymer, inkjet, or stereolithography enthusiasts.
By the early 2010s,
the terms 3D printing and additive manufacturing evolved senses in which
they were alternate umbrella terms for additive technologies, one being
used in popular vernacular by consumer-maker communities and the media,
and the other used more formally by industrial end-use part producers,
machine manufacturers, and global technical standards organizations.
Until recently, the term 3D printing has been associated with machines
low-end in price or in capability. Both terms reflect that the
technologies share the theme of material addition or joining throughout
a 3D work envelope under automated control. Peter Zelinski, the
editor-in-chief of Additive Manufacturing magazine, pointed out in 2017
that the terms are still often synonymous in casual usage but that some
manufacturing industry experts are increasingly making a sense
distinction whereby Additive Manufacturing comprises 3D printing plus
other technologies or other aspects of a manufacturing process.
Other
terms that have been used as synonyms or hypernyms have included desktop
manufacturing, rapid manufacturing (as the logical production-level
successor to rapid prototyping), and on-demand manufacturing (which
echoes on-demand printing in the 2D sense of printing). That such
application of the adjectives rapid and on-demand to the noun
manufacturing was novel in the 2000s reveals the prevailing mental model
of the long industrial era in which almost all production manufacturing
involved long lead times for laborious tooling development. Today, the
term subtractive has not replaced the term machining, instead
complementing it when a term that covers any removal method is needed.
Agile tooling is the use of modular means to design tooling that is
produced by additive manufacturing or 3D printing methods to enable
quick prototyping and responses to tooling and fixture needs. Agile
tooling uses a cost effective and high quality method to quickly respond
to customer and market needs, and it can be used in hydro-forming,
stamping, injection molding and other manufacturing processes.
History
1981
Early additive manufacturing equipment and materials were developed
in the 1980s. In 1981, Hideo Kodama of Nagoya Municipal Industrial
Research Institute invented two additive methods for fabricating
three-dimensional plastic models with photo-hardening thermoset polymer,
where the UV exposure area is controlled by a mask pattern or a scanning
fiber transmitter.
1984
On 16 July 1984, Alain Le Méhauté, Olivier de
Witte, and Jean Claude André filed their patent for the
stereolithography process. The application of the French inventors was
abandoned by the French General Electric Company (now Alcatel-Alsthom)
and CILAS (The Laser Consortium). The claimed reason was “for lack of
business perspective”.
Three weeks later in 1984, Chuck Hull of 3D
Systems Corporation filed his own patent for a stereolithography
fabrication system, in which layers are added by curing photopolymers
with ultraviolet light lasers. Hull defined the process as a “system
for generating three-dimensional objects by creating a cross-sectional
pattern of the object to be formed,”. Hull’s contribution was the STL
(Stereolithography) file format and the digital slicing and infill
strategies common to many processes today.
1988
The technology used by
most 3D printers to date—especially hobbyist and consumer-oriented
models—is fused deposition modeling, a special application of plastic
extrusion, developed in 1988 by S. Scott Crump and commercialized by his
company Stratasys, which marketed its first FDM machine in 1992.
AM
processes for metal sintering or melting (such as selective laser
sintering, direct metal laser sintering, and selective laser melting)
usually went by their own individual names in the 1980s and 1990s. At
the time, all metalworking was done by processes that we now call
non-additive (casting, fabrication, stamping, and machining); although
plenty of automation was applied to those technologies (such as by robot
welding and CNC), the idea of a tool or head moving through a 3D work
envelope transforming a mass of raw material into a desired shape with a
toolpath was associated in metalworking only with processes that removed
metal (rather than adding it), such as CNC milling, CNC EDM, and many
others. But the automated techniques that added metal, which would later
be called additive manufacturing, were beginning to challenge that
assumption. By the mid-1990s, new techniques for material deposition
were developed at Stanford and Carnegie Mellon University, including
microcasting and sprayed materials. Sacrificial and support materials
had also become more common, enabling new object geometries.
1993
The
term 3D printing originally referred to a powder bed process employing
standard and custom inkjet print heads, developed at MIT in 1993 and
commercialized by Soligen Technologies, Extrude Hone Corporation, and Z
Corporation.
The year 1993 also saw the start of a company called
Solidscape, introducing a high-precision polymer jet fabrication system
with soluble support structures, (categorized as a “dot-on-dot”
technique).
1995
In 1995 the Fraunhofer Institute developed the
selective laser melting process.
2009
Fused Deposition Modeling (FDM)
printing process patents expired in 2009. As the various additive
processes matured, it became clear that soon metal removal would no
longer be the only metalworking process done through a tool or head
moving through a 3D work envelope transforming a mass of raw material
into a desired shape layer by layer. The 2010s were the first decade in
which metal end use parts such as engine brackets and large nuts would
be grown (either before or instead of machining) in job production
rather than obligately being machined from bar stock or plate. It is
still the case that casting, fabrication, stamping, and machining are
more prevalent than additive manufacturing in metalworking, but AM is
now beginning to make significant inroads, and with the advantages of
design for additive manufacturing, it is clear to engineers that much
more is to come.
As technology matured, several authors had begun to
speculate that 3D printing could aid in sustainable development in the
developing world.
2013
NASA employees Samantha Snabes and Matthew
Fiedler create first prototype of large-format, affordable 3D printer,
Gigabot, and launch 3D printing company re:3D.
2018
re:3D develops a
system that uses plastic pellets that can be made by grinding up waste
plastic.
General principles
Modeling
3D printable models may be created
with a computer-aided design (CAD) package, via a 3D scanner, or by a
plain digital camera and photogrammetry software. 3D printed models
created with CAD result in reduced errors and can be corrected before
printing, allowing verification in the design of the object before it is
printed. The manual modeling process of preparing geometric data for 3D
computer graphics is similar to plastic arts such as sculpting. 3D
scanning is a process of collecting digital data on the shape and
appearance of a real object, creating a digital model based on it.
Printing
Before printing a 3D model from an STL file, it must first be
examined for errors. Most CAD applications (Fig. \ref{700002}.) produce errors in output STL
files of the following types: