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题目：A review of rapid prototyping integrated investment casting
processes
内容：
A review of rapid prototyping integrated investment casting
processes
Investment casting has been used to manufacture weapons, jewellery
and [url=http://www.wabonmetal.com/our-services/investment-casting/]
investment casting[/url] during the ancient civilization. Today, its
applications include jewellery/art castings, turbine blades and many
more industrial/scientific components. The present paper reviews
various investigations made by researchers in different stages of
investment casting and highlights their importance. The paper initially
highlights the investigations made on pattern wax properties, effects
of blending, additives and fillers. Different ways through which
pattern properties (like surface finish, dimensional accuracy, etc.)
could be enhanced by properly controlling the injection processing
parameters are thoroughly discussed. The paper also looks into the
investigations made to enhance the strength, surface finish, etc. of
ceramic shell for ferrous alloys/non-ferrous alloys as well as
superalloys in investment casting. Investigations made on incorporation
of nylon fibers and polymer additions confirm that a ceramic shell
reinforced with nylon fibers attains additional permeability compared
to the one with polymer additions.
Different investigations carried out on autoclave dewaxing and
microwave dewaxing conclude that the wax properties are less altered
with microwave dewaxing when compared to an autoclave dewaxing. Some
recent investigations carried out on pouring and post-treatment
operations are also discussed in the paper. The advent and emergence of
rapid prototyping in [url=http://www.wabonmetal.com/our-
services/shell-mold-casting/]shell mold casting [/url]are broadly
exposed in the subsequent sections of the paper. Various aspects of
rapid prototyping like rapid investment casting, rapid freeze
prototyping, etc., along with their advantages are projected. The
emerging areas of applications of rapid prototyping like dentistry,
etc., are duly discussed.
The casting of titanium based alloys presents considerable problems,
including the extensive interactions that occur between the metal and
refractory. In this work, CaO stabilised zirconia was used as a primary
coat material on the investment casting mould. The reaction between the
zirconia face-coat and a Ti-46Al-8Nb-1B alloy was evaluated at three
mould pre-heating temperatures: 500°C, 1000°C and 1200 °C. The
effect of casting dimensions on interaction was also included in this
work and the computer simulation of metal cooling profiles was carried
out to assist the analysis. Higher mould pre-heat temperature and
larger casting dimensions enhanced the interaction between the shell
and the TiAl alloy associated with longer metal solidification time.
During the high temperature casting process, not only were O and Zr
observed penetrating into the metal from the decomposition of the
face-coat materials, but also Si which had penetrated from the backup
coat was found to have interacted with the metal.
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