The Investment Casting Process |
| This detailed explanation of the investment casting
process is intended to help our customers learn about investment casting
to be able to make better purchasing decisions. |
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| WAX INJECTION |
| Replicas of the desired investment casting are produced by injection
molding or for smaller volumes using rapid prototyping (SLA or SLS). These
replicas are referred to as patterns. |
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| ASSEMBLY OF WAX TREE |
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| Wax Trees |
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| Patterns are then attached to a central wax stick, called a sprue, to
form a casting. This is called a wax tree. |
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| CERAMIC SHELL BUILDING |
| The shell is built by immersing the wax tree assembly in liquid ceramic
slurry and then into a bed of fluidized fine sands. Up to eight
layers may be applied in this manner depending on the shape and weight
of the part. |
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| DEWAX |
| Once the ceramic is dry, the wax is then melted out, creating a negative
impression of the assembly within the ceramic and sand shell. This
process uses autoclaves to maintain shell integrity. |
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| CONVENTIONAL CASTING |
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| Transfer Ladel |
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| In the conventional lost wax casting process, the preheated shell (up
to 1800 deg F) is filled with molten metal by gravity pouring the metal
into the ceramic shell. As the metal cools, the parts, gates, sprue
and pouring cup become one solid casting. Shell temperature and
melt temperature will vary depending on the alloy. |
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| KNOCKOUT |
| Once the metal is cooled and solid, the ceramic shell is broken off by
vibration or water blastig. |
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| CUT OFF OF PARTS |
| The parts are then cut away from the central sprue using a high speed
saw. |
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| FINISHED METAL INVESTMENT CASTINGS |
| After minor finishing operations, or possible required machining operations,
the metal investment castings--identical to the original wax patterns--are
ready for shipment to the customer from our metal investment casting China foundry. We are able to provide finished stainless steel investment
casting, steel investment casting, aluminum investment casting, cobalt
alloy investment casting, nickel alloy investment casting and precision
investment castings. |
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| WALL THICKNESS |
| Please call for tolerance specifications for wall thickness or any tolerances
in general. Depending on the metal or alloy, minimum wall thickness
can range from 0.04 inches to 0.08 inches. |