Lost Wax Process

This process became common in industrial processing during World War II, when a demand for rapidly finished parts and "near net-shape" components requiring complex, often thin-wall castings, that could readily be put into final form. The industrialization of this process was made feasible by the development of new, inorganic, high-temperature ceramic mold binders to process applications that include high strength and corrosion resistant materials. Such materials include low- to high-carbon alloy steel, stainless steel, tool steel; aluminum and brass as well as nickel and cobalt base alloys are also used.

Generally, the process entails making an injection-molded wax pattern for each part produced. These injection molds are then encased in multiple layers of ceramic material partly composed of a specialty plaster like Denscal® IC. Then the wax pattern is removed from the ceramic shell by firing it in a oven. Molten metal is then poured into the ceramic cavities left by the dewaxed pattern. Once the precision castings are cooled, they can be cleaned using high-pressure water, vibratory or shot blast methods. Then the individual castings are removed from the cluster and subjected to further processing such as heat treatment or grinding. Generally, the castings are sand blasted or buffed for a smoother finish.