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Investment Casting Process
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1. Wax Injection Wax replicas of the desired castings are produced by injection molding. These replicas are called patterns. |
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2. Assembly The patterns are attached to a central wax stick, called a sprue, to form a casting cluster or assembly. |
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3. Shell Building The shell is built by immersing the assembly in a liquid ceramic slurry and then into a bed of extremely fine sand. Up to eight layers may be applied in this manner. |
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4. Dewax Once the ceramic is dry, the wax is melted out, creating a negative impression of the assembly within the shell. |
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5. Conventional Casting In the conventional process, the shell is filled with molten metal by gravity pouring. As the metal cools, the parts and gates, sprue and pouring cup become one solid casting. (Hitchiner prefers to use its superior countergravity casting technology.) |
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6.Knockout When the metal has cooled and solidified, the ceramic shell is broken off by vibration or water blasting. |
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7. Cut Off The parts are cut away from the central sprue using a high speed friction saw. |
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8.Finished Castings After minor finishing operations, the metal castings--identical to the original wax patterns--are ready for shipment to the customer. |
