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What is Investment Casting?
Investment casting / precision casting or the
"lost wax" process has been in use since the construction of the
first pyramid. The Egyptians and Chinese used the process in their
early history to make jewellery and statues. The investment casting
method was largely ignored as an industrial process for the
fabrication of parts until the demand for rapidly finished parts
during World War II created the need for "near net-shape" components
that could readily be put into their final form. At this time new
inorganic high temperature ceramic mold binders were developed to
industrialize the process applications to include high strength and
corrosion resistant materials such as low to high carbon alloy
steel, tool steel, stainless steel, and nickel and cobalt base
alloys. Aluminum and brass alloys are available also.
It is a process capable of producing intricate
shapes weighing from a small fraction of an grams up to 20 Kg. or
more. Some examples would be: aircraft structural parts, components
for the automotive industry, military weaponry, jet engines,
machinery components, dental appliances, jewelry and many others.
In general, an injection molded wax pattern is
used for each part produced which is then encased in multiple layers
of ceramic material. The wax pattern is then removed from the
ceramic shell mold. The mold is fired in an oven and then molten
metal is poured into the cavities left by the evacuated wax pattern.
Upon cooling, the resulting precision casting are cleaned and
subjected to further processing such as heat treatment. At this
point, many parts are in their final form and are ready for use
while others may require a small amount of further processing such
as machining before reaching their final form.
Why Investment Casting?
FLEXIBILITY IN DESIGNING
Investment casting produces near-net-shape
configurations, offering engineers and designers freedom of design
in a wide range of alloys. The process is capable of producing
precise detail and dimensional accuracy in parts weighing many Kg or
just a few grams.
WIDE CHOICE OF ALLOYS
More than 125 ferrous and nonferrous metals are
routinely cast.
TOOLING SET-UP IS ELIMINATED
By offering near-net-shape configuration,
fix turning costs are substantially reduced or eliminated.
REDUCE PRODUCTION COSTS & ENHANCE PROFITABILITY
Costly machining operations are reduced and
often eliminated. No capital equipment investment is needed to
produce parts in-house.
CUT ASSEMBLY OPERATIONS
Several parts can be made as one casting,
reducing handling, assembly and inspection costs.
REPRODUCE FINE DETAILS
Spines, bosses, serrations, lettering, holes
and even some threads can be cast.
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