Investment Casting Process

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Based on a drawing or three dimensional file, an aluminum die is generated.  The die is the only reusable item in the production process.

Melted wax is injected into the die, creating an exact wax replica of the part.  One wax pattern must be injected for every finished part.  In the case of a prototype, a heat disposable pattern is generated using a CAD file.

The wax patterns are fastened to a wax sprue to form an assembly.  Depending on size and geometry, an assembly can have from 1 to 100+ waxes attached.

The assembly is dipped in a liquid ceramic slurry, then covered in a fine zircon or silica sand. This process is repeated until the shell is strong enough to withstand the thermal shock and stresses of the casting operation.

The shell is placed in an autoclave, where the wax is removed using steam and pressure, leaving behind cavities in the shell in the exact shape of the desired casting.

The shell is fired in an oven to prepare it for pouring.

Molten metal is poured into the preheated shell.

After the metal has solidified and the mold is cooled, the shell is removed.

The individual castings are cut from the metal assembly using a vertical or abrasive saw.

Remnants of the gates that attached the casting to the assembly are removed through grinding.

Finishing operations such as heat treating, straightening, abrasive blasting, and non destructive testing can now be done to prepare the casting for secondary operations or delivery.