Investment Casting Process

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How We Make It — finished investment casting component

The investment casting process begins with machining the wax pattern injection molds

The molds are checked for specification compliance and maintained to investment casting standards

To generate a wax pattern, liquid or paste wax is injected into the machined mold

The wax pattern is identical to the completed precision investment casting in precise detail

A number of wax patterns make up this production lot

The wax patterns are inspected; defective wax patterns are repaired or scrapped

Multiple wax patterns are assembled on a frame, commonly referred to as a tree

The assembly is coated with a fine ceramic liquid slurry

While the slurry is still wet, the assembly is completely covered with a fine sand

The assembly dries for 24 hours or more depending on the configuration

Layers of slurry and sand are applied to build a strong, thin ceramic shell, drying completely between applications

This is a completed ceramic shell, or ceramic mold

The ceramic shells are processed in a steam autoclave to melt out the wax

The ceramic shell is cured in a 1600–1800°F oven, adding strength and burning out residual wax

The fired ceramic shells are preheated before the molten metal is poured

The metal is melted and degassed in a crucible lined furnace and poured into the ceramic shell

The assembly cools to room temperature, the shell is removed and the metal investment casting is the shape of the assembly

The assembly is cleaned of ceramic with a high pressure water blast

The unwanted gates and risers are sawed off

Gates and risers are further removed by rough grinding with a belt sander

Any de-burring or hand finishing is done

Physical properties are improved with heat treating

Sandblasting presents a clean and uniform finish

Fluorescent penetrant inspection identifies otherwise undetectable surface flaws

X-ray reveals any flaws below the surface of the investment casting

A tensile testing machine measures the amount of force required to break a test bar

A spectrometer analyzes the chemistry and metallurgical properties of each casting lot

Tolerances are measured with a coordinate measuring machine and hand measuring tools

CNC machining provides precision machined investment castings

Each part is evaluated for packaging, ensuring parts arrive without damage

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AlCuMet is a world class leader in investment casting. We serve the aerospace, defense and other industries with precision investment castings.

Investment casting is one of the oldest manufacturing processes, dating back thousands of years, in which molten metal is poured into an expendable ceramic mold. The mold is formed by using a wax pattern — a disposable piece in the shape of the desired part. The pattern is surrounded, or invested, into ceramic slurry that hardens into the mold.

Investment casting is often selected over other metalworking processes when: the part is too complex or too costly to machine, the part requires tight tolerances, the part is made from a metal that is difficult to machine or fabricate, large quantities of the part are required.

Fulfilling all your new and existing casting needs.

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Investment Casting Process — AlCuMet Inc.