Page 558 - 04. Subyek Engineering Materials - Manufacturing, Engineering and Technology SI 6th Edition - Serope Kalpakjian, Stephen Schmid (2009)

38 Chapter 20 Rapid-Prototyping Processes and Operations

(H) (D)
Rapid-prototyped versions of user-defined characters, or avatars, produced from geometric
FIGURE 20.l I
descriptions within popular websites or games. (a) Second Life® avatar, as appears on a computer screen (left)
and after printing (right); (b) an avatar known as “Wreker” from World of \X/arcraft®. Source: Courtesy
Z Corporation, Figure Prints and Fabjectory, Inc.

three-dimensional geometry data that describes their 450 three-dimensional printers (Fig 2O.11). Users can
appearance, which can be translated to a file format order their avatar prototypes on the web, which are
suitable for rapid prototyping. then printed and shipped to the user within days.
Avatars can be printed in full color to a 150-mm
high figurine with Z-Corp Spectrum Z51O or ZPrinter

EXAMPLE 20.4 Fuselage Fitting for Helicopters
Sikorsky Aircraft Company needed to produce a was followed by curing of the binder (10 hours, plus
limited number of the fuselage fittings shown in 5 hours for cooldown), sintering (40 hours, plus
Fig. 20.12a. Sikorsky wanted to produce the forging 17 hours for cooldown), and infiltration (27 hours,
dies by means of three-dimensional-printing tech- plus 15 hours for cooldown). The dies then were
nologies. A die was designed using the CAD part finished and positioned in a die holder, and the part
description. Forging allowances were incorporated was forged in an 800-ton hydraulic press with a die
and flashing accommodated by the die design. temperature of around 300°C. An as-forged part is
The dies were printed using a three~ shown in Fig. 20.12c and requires trimming of the
dimensional printer produced by ProMetal and flash before it can be used. The dies were produced in
are shown in Fig. 20.12b. The dies were made by just over six days-compared with the many months
producing 0.178-mm layers with stainless-steel required for conventional die production.
powder as the workpiece media. The total time spent
in the 3DP machine was just under 45 hours. This Source: Courtesy of Kennametal Extrude Hone.