In investment casting a wax pattern is coated with a refractory ceramic material, which hardens and takes the shape of the casting, forming the required internal geometry. The wax is then removed from the mold by melting, and molten metal replaces the wax in the cavity.
The metal casting is broken out of the mold once the metal has solidified in the required shape. In manufacturing units in India, this process is also referred to as the lost wax process. Developed more than 5500 years ago, investment casting can trace its roots back to ancient China and Egypt. Parts with complex geometries including machinery components, turbine blades, jewelry, ratchets, cams, gears, and dental fixtures are typically parts that are produced using the investment casting method.
Advantages Investment casting is a manufacturing process that allows the casting of extremely complex parts, with good surface finish.
Very thin sections can be produced by this process. Metal castings with sections as narrow as .015in (.4mm) have been manufactured using investment casting.
Investment casting also allows for high dimensional accuracy. Tolerances as low as .003in (.076mm) have been claimed.
Practically any metal can be investment cast. Parts manufactured by this process are generally small, but parts weighing up to 75lbs have also been made suitablywith this technique.
Parts of the investment process may be automated.