About Investment casting

Investment casting is also known as the lost wax process. The process has been known and used for centuries. It was carried into modern industrial use during World War II when the manufacturers applied investment casting to produce high quality military parts. It was found practical for many wartime needs. Today, investment casting is recognized and used worldwide as a technique to produce high quality intricate metal parts.
The investment casting process begins by production a wax pattern employing a precision mold. The wax patterns are fastened by the gate to a runner to form a cluster. The cluster is dipped in refractory slurry and coated with fine sand then dried. The process of dipping and drying is repeated until a robust thickness is achieved. After this, the ceramic shell is heated, and the wax is melted away. This leads the mold into a cavity that can be filled with the molten metal. The hollow mold is fired, and the liquid alloy is poured into the pre-heated mold. After the metal has solidified, the slurry shell is broken off and the individual part is cut away from the connecting gates. The parts are cleaned and subjected to further secondary operations.

Investment castings have significant advantages over other manufacturing technologies. Investment casting:

‧Allows for greater flexibility and more sophisticated part design
‧Can cast close to the tolerances to reduce costs of tooling and machining
‧Can sculpt monolithic cast structures that replace multi-piece fabrications
‧Can utilize a wide variety of alloys
‧Yields good mechanical properties and smooth surface
‧Provides a reliable and consistent reproducibility

A highly versatile casting process is perceived as a comparatively expensive process sometimes. However, when compare it to alternative processes which require extensive welding or machining, investment casting often reduces overall part production costs dramatically because of the complex configurations and close tolerances that can be achieved. Of course, investment casting is not the appropriate process for every metal part. However, for many challenging part applications, investment casting offers an advanced metal forming solution for exceptional accuracy, complexity, and fine detail reproduction at the highly competitive cost.