Learn more about the Investment Casting Process…..

The Investment Casting Process…

Also Known as The Lost Wax Casting Process….

The investment casting process, often referred to as lost-wax casting, is a method widely used in the manufacturing industry for creating intricate and detailed metal components. In this process, the desired object is first formed by creating a wax pattern (using 3D Printing or via hard tooling) which is then coated with a ceramic material to form a mould. Once the mould is created, the wax is melted and drained away, leaving behind a cavity in the shape of the desired part. Molten metal is then poured into the mould, filling the void, and taking on the shape of the original wax pattern. After the metal solidifies, the ceramic mould is broken away, revealing the finished metal part.

The investment casting process offers numerous advantages, including the ability to create complex and intricate parts with high accuracy and detail. While it may involve multiple steps and processes, the end result is a finished metal component that meets the exact requirements of the intended application. There is little metal wastage due to the nature of the investment casting process, but what little there is, can be recycled. The melted wax patterns are also recycled.

Explained in 9 Steps

Wax Making Process

1. Wax Making

Wax replicas of the desired castings are produced by injection moulding using a metal die or 3D printing. These replicas are called “patterns”.

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2. Wax Assembly

These patterns are attached via a ‘gate’ to a central wax stick, referred to as a ‘tree’ or ‘sprue’, to form a casting cluster or assembly, and mounted on a pouring cup.

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3. Investing

 A shell is built by immersing the assembly in a liquid ceramic slurry and then into a bed of extremely fine sand. Several layers may be applied in this manner.

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4. Dewaxing

Once the ceramic is dry, the wax is melted out in an autoclave, creating a negative impression of the assembly within the shell. The shell mould is then fired in a high temperature oven.

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5. Casting

The shell is filled with molten metal – metal injection moulding in a variety of materials, using various techniques and, as the metal cools, the parts, gates, tree and pouring cup become a solid casting.

Knock out Lestercast

6. Knock out

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 tree using a high speed friction saw.

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8. Finishing

 Minor finishing operations, such as fettling and grinding, are undertaken to produce a metal casting identical to the original wax pattern.

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9. Inspection

The finished component will then be checked for surface defects, and imperfections using gauges, calipers or further analysis using CMM.

Want to see The Investment Casting Process in Action?

Watch our Video Now  ›

Step inside our laboratory to see the wax patterns being assembled, watch the waxes being dipped in the slurry, see the ceramic coated waxes drying in our dedicated drying rooms and take a sneaky peak at the foundry to watch the ceramics being fired and the molten metal poured…..