mass-customized products, prototypes, replace-
ment parts, and medical/dental components. These
applications are typically high-value objects that
are either customized or produced in very small
quantities. With mass-customized products, retailers can
position 3-D printers in a store and create custom-
ized products for patrons. Via one application,
custom-made shoes can be designed specifically
for an individual based on his/her foot size and
walking gait. While these are currently more expen-
sive than mass-produced shoes, experts feel the
price differential will shrink over time. 3-D printing has been extensively used in the
development of prototypes. While objects can be
seen in three dimensions on a computer screen,
many designers and new-product planners would
rather examine, touch, and hold an item before
committing to a large investment. Unlike clay ,
wood, or metal mockups that have in the past been
created by hand, 3-D machines can produce objects
with moving parts (such as a working model of a
bicycle chain or even a small gearbox) and can
utilize multiple materials (such as a plastic remote
control with rubber-like buttons). A second major
advantage in prototype development is the ability of
3-D printing to produce prototypes quickly and to
make different versions, for consumer versus lab
testing and for different market segments, without
the need for costly retooling. Shoe manufacturer Timberland used to spend
roughly $1,200 and 1 week of time in designing a
new sole for one of its shoe models. Using a 3-D
printer , however , a model can be produced in
90 minutes for a cost of $35 (‘ ‘Case History ,’ ’
2009). Alessi, an Italian manufacturer of high-quality
housewares, has also used 3-D printers to develop
plastic prototypes of new products. According to
Alessi’s prototype manager , 3-D printing cut 5 - 6
weeks from its new-product development process. It
also costs Alessi about 70% less than the traditional
method of making prototypes (‘ ‘3D Systems,’ ’ 2011). Architectural firms are using 3-D printing to cre-
ate models of buildings and resort complexes. Ac-
cording to the founder of a firm that specializes in
architectural applications of 3-D printing, it used to
take 2 months and $100,000 to build models; now ,
the firm is building $2,000 models in one evening
with 3-D printing (Vance, 2010a). 3-D printing is an ideal technology for making
replacement parts for washing machines and food
processors, as well as camera lens accessories and
small gears (Bradshaw , Bowyer , & Haufe, 2010). Using injection molding technologies, replacement
parts manufacturers had to turn out large quantities
at a time. This has resulted in uncertain demand,
low inventory turnover , and high storage costs. With
3-D printing, though, these parts can be made on an
as-needed basis. In some cases, replacement parts
have even been produced by third-party providers
utilizing designs provided by the products’ manu-
facturer . Due to improvements in precision, detail, and
surface finish, 3-D printing has been increasingly
used for such medical applications as hearing aid
molds, dental crowns, and prosthetic limbs. Since
an individual’s ear canal is unique in size and shape,
a hearing aid needs to fit perfectly for optimal
performance. Using CAD software, the contours of
a patient’s ear can be digitized within minutes. And
within hours, a custom-made hearing aid shell can
be produced from liquid photopolymer via 3-D print-
ing (Alpern, 2010). For their part, dental labs can use 3-D technology
to handle digital files in-house without the need for
physical impressions. As a result of this technology ,
labs are able to complete a dental restoration within
3 days of the intraoral scan (‘ ‘Dentistry ,’’ 2011). Medical companies have also used 3-D printing to
make patient-specific knee replacements that mim-
ic the patient’s own anatomy; CTscan data permits a
custom fit, unlike those provided by standard mod-
els. Bespoke Innovations sells dishwasher-safe cus-
tomized limbs that cost a tenth of comparable
artificial limbs made using traditional methods
(Vance, 2010b). Porous scaffolds that resemble nat-
ural bone structure have recently been developed
for use in 3-D printing. These materials make the
implant function almost as an integral part of the
body (Sedacca, 2011). 3-D printing has applications in the testing of
medical procedures, physician training, and evalu-
ation of medical devices. Orthopedic surgeons at
Walter Reed Medical Center have developed models
of the human knee using 3-D printing technologies. These models have been used for surgical proce-
dures when a wound is near a nerve/arterial junc-
tion, with little tolerance for error (King, 2008).