. .It
costs the same to produce two different variants as
two identical ones. The economies-of-scale  ratio-
nale of serial production does not apply’ ’ (Thilmany ,
2009, p. 39). A senior CAD designer for running shoe
manufacturer  New Balance adds that the company’s
3-D printing machines ‘‘ r u n pretty much nonstop.’ ’
Each machine produces up to 100 models a month
(Pullin, 2009). Less-expensive materials can also be used in
prototype and mockup development. For example,
when appearance is the major consideration, pro-
totype parts can be produced from plastic materials
and resins while the actual objects are made from
metals. Prototype development costs and time re-
quirements are also significantly reduced since no
tools and dyes are required in 3-D printing. Savings
in tools and dyes can result in hundreds of thousands
of dollars. The manager of technology at Black &
Decker reported that prior to using 3-D printers, it
would typically take 3 - 5 days to get a prototype
back from the service bureau. With 3-D printers
onsite, however , prototypes can be produced in just
a few hours (‘‘Simplifying,’’ 2010). Finally , security
and privacy issues are not a concern because 3-D
printing enables in-house production. The second evolutionary phase of 3-D printers
involves their use in creating finished goods. This
stage is sometimes referred to as ‘direct digital
manufacturing’ or ‘rapid tooling.’ A popular second
phase application is larger production runs that en-
compass bridge manufacturing and the manufactur-
ing of goods to be used in test marketing. In test
marketing, multiple prototypes– —different sizes,
styles, and colors– —can be more easily produced
and market tested. According to T erry Wohlers, man-
ager of a market research firm specializing in 3-D
printing, over 20% of the output of 3-D printers is now
in final products as opposed to prototypes (‘ ‘3-D
Printing: The Printed World,’ ’ 2010). Wohlers predicts
that this will rise to 50% by 2020. In the third phase, 3-D printers will be owned and
used by final consumers, just like traditional desk-
top laser printers. A co-founder of the firm that
makes the $750 CupCake CNC 3-D printer said:
‘‘My hope is that people, instead of going to the
store, will go online and download what they need
and print it out’’ (Olivarez, 2010, p. C4).